style(core): fix some codestyle issues

1 files changed, 878 insertions, 871 deletions

diff --git a/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/signing/pdfbox2/PADESPDFBOXSigner.java b/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/signing/pdfbox2/PADESPDFBOXSigner.java
index 3e1b7d9a..d780aeec 100644
--- a/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/signing/pdfbox2/PADESPDFBOXSigner.java
+++ b/pdf-as-pdfbox-2/src/main/java/at/gv/egiz/pdfas/lib/impl/signing/pdfbox2/PADESPDFBOXSigner.java
@@ -23,6 +23,58 @@
  ******************************************************************************/
 package at.gv.egiz.pdfas.lib.impl.signing.pdfbox2;
 
+import java.awt.Graphics2D;
+import java.awt.Image;
+import java.awt.image.BufferedImage;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.Calendar;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import javax.activation.DataSource;
+
+import org.apache.commons.io.IOUtils;
+import org.apache.pdfbox.cos.COSArray;
+import org.apache.pdfbox.cos.COSBase;
+import org.apache.pdfbox.cos.COSDictionary;
+import org.apache.pdfbox.cos.COSDocument;
+import org.apache.pdfbox.cos.COSInteger;
+import org.apache.pdfbox.cos.COSName;
+import org.apache.pdfbox.cos.COSString;
+import org.apache.pdfbox.pdmodel.PDDocument;
+import org.apache.pdfbox.pdmodel.PDDocumentCatalog;
+import org.apache.pdfbox.pdmodel.PDPage;
+import org.apache.pdfbox.pdmodel.PDResources;
+import org.apache.pdfbox.pdmodel.common.COSObjectable;
+import org.apache.pdfbox.pdmodel.common.PDMetadata;
+import org.apache.pdfbox.pdmodel.common.PDNumberTreeNode;
+import org.apache.pdfbox.pdmodel.common.PDRectangle;
+import org.apache.pdfbox.pdmodel.documentinterchange.logicalstructure.PDStructureElement;
+import org.apache.pdfbox.pdmodel.documentinterchange.logicalstructure.PDStructureTreeRoot;
+import org.apache.pdfbox.pdmodel.graphics.color.PDOutputIntent;
+import org.apache.pdfbox.pdmodel.interactive.digitalsignature.PDSignature;
+import org.apache.pdfbox.pdmodel.interactive.digitalsignature.SignatureOptions;
+import org.apache.pdfbox.pdmodel.interactive.form.PDAcroForm;
+import org.apache.pdfbox.pdmodel.interactive.form.PDField;
+import org.apache.pdfbox.pdmodel.interactive.form.PDSignatureField;
+import org.apache.pdfbox.preflight.PreflightDocument;
+import org.apache.pdfbox.preflight.ValidationResult;
+import org.apache.pdfbox.preflight.exception.SyntaxValidationException;
+import org.apache.pdfbox.preflight.exception.ValidationException;
+import org.apache.pdfbox.preflight.parser.PreflightParser;
+import org.apache.pdfbox.rendering.ImageType;
+import org.apache.pdfbox.rendering.PDFRenderer;
+import org.apache.xmpbox.XMPMetadata;
+import org.apache.xmpbox.schema.PDFAIdentificationSchema;
+import org.apache.xmpbox.xml.DomXmpParser;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import at.gv.egiz.pdfas.common.exceptions.PDFASError;
 import at.gv.egiz.pdfas.common.exceptions.PdfAsException;
 import at.gv.egiz.pdfas.common.messages.MessageResolver;
@@ -36,7 +88,6 @@ import at.gv.egiz.pdfas.lib.impl.SignaturePositionImpl;
 import at.gv.egiz.pdfas.lib.impl.configuration.PlaceholderWebConfiguration;
 import at.gv.egiz.pdfas.lib.impl.configuration.SignatureProfileConfiguration;
 import at.gv.egiz.pdfas.lib.impl.pdfbox2.PDFBOXObject;
-import at.gv.egiz.pdfas.lib.impl.pdfbox2.placeholder.SignaturePlaceholderExtractor;
 import at.gv.egiz.pdfas.lib.impl.pdfbox2.positioning.Positioning;
 import at.gv.egiz.pdfas.lib.impl.pdfbox2.utils.PdfBoxUtils;
 import at.gv.egiz.pdfas.lib.impl.placeholder.PlaceholderFilter;
@@ -58,952 +109,908 @@ import at.knowcenter.wag.egov.egiz.pdf.PositioningInstruction;
 import at.knowcenter.wag.egov.egiz.pdf.TablePos;
 import at.knowcenter.wag.egov.egiz.table.Table;
 import iaik.x509.X509Certificate;
-import org.apache.commons.io.IOUtils;
-import org.apache.pdfbox.cos.*;
-import org.apache.pdfbox.pdmodel.PDDocument;
-import org.apache.pdfbox.pdmodel.PDDocumentCatalog;
-import org.apache.pdfbox.pdmodel.PDPage;
-import org.apache.pdfbox.pdmodel.PDResources;
-import org.apache.pdfbox.pdmodel.common.COSObjectable;
-import org.apache.pdfbox.pdmodel.common.PDMetadata;
-import org.apache.pdfbox.pdmodel.common.PDNumberTreeNode;
-import org.apache.pdfbox.pdmodel.common.PDRectangle;
-import org.apache.pdfbox.pdmodel.documentinterchange.logicalstructure.PDStructureElement;
-import org.apache.pdfbox.pdmodel.documentinterchange.logicalstructure.PDStructureTreeRoot;
-import org.apache.pdfbox.pdmodel.graphics.color.PDOutputIntent;
-import org.apache.pdfbox.pdmodel.interactive.digitalsignature.PDSignature;
-import org.apache.pdfbox.pdmodel.interactive.digitalsignature.SignatureOptions;
-import org.apache.pdfbox.pdmodel.interactive.form.PDAcroForm;
-import org.apache.pdfbox.pdmodel.interactive.form.PDField;
-import org.apache.pdfbox.pdmodel.interactive.form.PDSignatureField;
-import org.apache.pdfbox.preflight.PreflightDocument;
-import org.apache.pdfbox.preflight.ValidationResult;
-import org.apache.pdfbox.preflight.exception.SyntaxValidationException;
-import org.apache.pdfbox.preflight.exception.ValidationException;
-import org.apache.pdfbox.preflight.parser.PreflightParser;
-import org.apache.pdfbox.rendering.ImageType;
-import org.apache.pdfbox.rendering.PDFRenderer;
-import org.apache.xmpbox.XMPMetadata;
-import org.apache.xmpbox.schema.PDFAIdentificationSchema;
-import org.apache.xmpbox.xml.DomXmpParser;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import javax.activation.DataSource;
-import java.awt.*;
-import java.awt.image.BufferedImage;
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.InputStream;
-import java.util.ArrayList;
-import java.util.Calendar;
-import java.util.Collections;
-import java.util.LinkedHashMap;
-import java.util.List;
-import java.util.Map;
 
 public class PADESPDFBOXSigner implements IPdfSigner, IConfigurationConstants {
 
-	private static final Logger logger = LoggerFactory.getLogger(PADESPDFBOXSigner.class);
-	private boolean isAdobeSigForm = false;
+  private static final Logger logger = LoggerFactory.getLogger(PADESPDFBOXSigner.class);
+  private boolean isAdobeSigForm = false;
 
-	public void signPDF(PDFObject genericPdfObject, RequestedSignature requestedSignature,
-			PDFASSignatureInterface genericSigner) throws PdfAsException {
+  @Override
+  public void signPDF(PDFObject genericPdfObject, RequestedSignature requestedSignature,
+      PDFASSignatureInterface genericSigner) throws PdfAsException {
 
-		PDFAsVisualSignatureProperties properties = null;
-		List<SignaturePlaceholderData> placeholders;
-		List<SignaturePlaceholderData> availablePlaceholders;
-		SignaturePlaceholderData signaturePlaceholderData = null;
+    PDFAsVisualSignatureProperties properties = null;
+    List<SignaturePlaceholderData> placeholders;
+    List<SignaturePlaceholderData> availablePlaceholders;
+    SignaturePlaceholderData signaturePlaceholderData = null;
 
-		String placeholder_id = "";
-
-		if(PlaceholderWebConfiguration.getValue(PLACEHOLDER_WEB_ID) != null  && !PlaceholderWebConfiguration.getValue(PLACEHOLDER_WEB_ID).equalsIgnoreCase("")){
-			placeholder_id = PlaceholderWebConfiguration.getValue(PLACEHOLDER_WEB_ID);
-		}
+    String placeholder_id = "";
 
+    if (PlaceholderWebConfiguration.getValue(PLACEHOLDER_WEB_ID) != null && !PlaceholderWebConfiguration
+        .getValue(PLACEHOLDER_WEB_ID).equalsIgnoreCase("")) {
+      placeholder_id = PlaceholderWebConfiguration.getValue(PLACEHOLDER_WEB_ID);
+    }
 
-		if (!(genericPdfObject instanceof PDFBOXObject)) {
-			// tODO:
-			throw new PdfAsException();
-		}
+    if (!(genericPdfObject instanceof PDFBOXObject)) {
+      // tODO:
+      throw new PdfAsException();
+    }
 
-		PDFBOXObject pdfObject = (PDFBOXObject) genericPdfObject;
+    final PDFBOXObject pdfObject = (PDFBOXObject) genericPdfObject;
 
-		if (!(genericSigner instanceof PDFASPDFBOXSignatureInterface)) {
-			// tODO:
-			throw new PdfAsException();
-		}
+    if (!(genericSigner instanceof PDFASPDFBOXSignatureInterface)) {
+      // tODO:
+      throw new PdfAsException();
+    }
 
-		PDFASPDFBOXSignatureInterface signer = (PDFASPDFBOXSignatureInterface) genericSigner;
+    final PDFASPDFBOXSignatureInterface signer = (PDFASPDFBOXSignatureInterface) genericSigner;
+
+    String pdfaVersion = null;
+
+    PDDocument doc = null;
+    final SignatureOptions options = new SignatureOptions();
+    COSDocument visualSignatureDocumentGuard = null;
+    try {
+
+      doc = pdfObject.getDocument();
+      // if signature already exists dont create new page
+      final List<PDSignatureField> pdSignatureFieldList = doc.getSignatureFields();
+      PDSignature signature;
+
+      // sign a PDF with an existing empty signature, as created by the
+      // CreateEmptySignatureForm example.
+      String sigFieldName = pdfObject.getStatus().getSettings().getValue(SIGNATURE_FIELD_NAME);
+      signature = findExistingSignature(doc, sigFieldName);
+      if (signature == null) {
+        // create signature dictionary
+        signature = new PDSignature();
+      } else {
+        isAdobeSigForm = true;
+      }
+
+      signature.setFilter(COSName.getPDFName(signer.getPDFFilter()));
+      signature.setSubFilter(COSName.getPDFName(signer.getPDFSubFilter()));
+//			SignaturePlaceholderData signaturePlaceholderDataInit =
+      placeholders = PlaceholderFilter.checkPlaceholderSignatureLocationList(pdfObject.getStatus(),
+          pdfObject.getStatus().getSettings(), placeholder_id);
 
-        String pdfaVersion = null;
+//            placeholders = SignaturePlaceholderExtractor.getPlaceholders();
+      availablePlaceholders = listAvailablePlaceholders(placeholders, existingSignatureLocations(doc));
 
-		PDDocument doc = null;
-		SignatureOptions options = new SignatureOptions();
-		COSDocument visualSignatureDocumentGuard = null;
-		try {
+      if (placeholder_id.equalsIgnoreCase("")) {
+        if (checkAvailablePlaceholders(placeholders, existingSignatureLocations(doc)) != null) {
+          placeholder_id = checkAvailablePlaceholders(placeholders, existingSignatureLocations(doc)).getId();
+        }
+      }
+
+      if (availablePlaceholders != null) {
+        signaturePlaceholderData = PlaceholderFilter
+            .checkPlaceholderSignatureLocation(pdfObject.getStatus(), pdfObject.getStatus().getSettings(),
+                placeholder_id);
+      }
+
+      TablePos tablePos = null;
+
+      if (signaturePlaceholderData != null) {
+        signature.setLocation(signaturePlaceholderData.getPlaceholderName());
+      }
+
+      if (signaturePlaceholderData != null) {
+        // Placeholder found!
+        placeholders.clear();
+        logger.info("Placeholder data found.");
+        if (signaturePlaceholderData.getProfile() != null) {
+          logger.debug("Placeholder Profile set to: " + signaturePlaceholderData.getProfile());
+          requestedSignature.setSignatureProfileID(signaturePlaceholderData.getProfile());
+        }
 
-			doc = pdfObject.getDocument();
-			//if signature already exists dont create new page
-			List<PDSignatureField> pdSignatureFieldList = doc.getSignatureFields();
-			PDSignature signature;
+        tablePos = signaturePlaceholderData.getTablePos();
+        if (tablePos != null) {
 
-			// sign a PDF with an existing empty signature, as created by the CreateEmptySignatureForm example.
-			String sigFieldName = pdfObject.getStatus().getSettings().getValue(SIGNATURE_FIELD_NAME);
-			signature = findExistingSignature(doc, sigFieldName);
-			if (signature == null) {
-				// create signature dictionary
-				signature = new PDSignature();
-			}
-			else {
-				isAdobeSigForm = true;
-			}
+          final SignatureProfileConfiguration signatureProfileConfiguration = pdfObject.getStatus()
+              .getSignatureProfileConfiguration(requestedSignature.getSignatureProfileID());
 
-			signature.setFilter(COSName.getPDFName(signer.getPDFFilter()));
-			signature.setSubFilter(COSName.getPDFName(signer.getPDFSubFilter()));
-//			SignaturePlaceholderData signaturePlaceholderDataInit =
-			placeholders = PlaceholderFilter.checkPlaceholderSignatureLocationList(pdfObject.getStatus(),
-							pdfObject.getStatus().getSettings(), placeholder_id);
+          final float minWidth = signatureProfileConfiguration.getMinWidth();
 
-//            placeholders = SignaturePlaceholderExtractor.getPlaceholders();
-            availablePlaceholders = listAvailablePlaceholders(placeholders, existingSignatureLocations(doc));
-
-
-			if(placeholder_id.equalsIgnoreCase("")){
-				if(checkAvailablePlaceholders(placeholders,existingSignatureLocations(doc))!=null)
-				{
-					placeholder_id = (checkAvailablePlaceholders(placeholders, existingSignatureLocations(doc))).getId();
-				};
-			}
-
-			if(availablePlaceholders!=null) {
-				signaturePlaceholderData = PlaceholderFilter
-						.checkPlaceholderSignatureLocation(pdfObject.getStatus(), pdfObject.getStatus().getSettings(),placeholder_id);
-			}
-
-
-
-
-			TablePos tablePos = null;
-
-			if(signaturePlaceholderData!=null)
-			signature.setLocation(signaturePlaceholderData.getPlaceholderName());
-
-			if (signaturePlaceholderData != null) {
-				// Placeholder found!
-                placeholders.clear();
-                logger.info("Placeholder data found.");
-				if (signaturePlaceholderData.getProfile() != null) {
-					logger.debug("Placeholder Profile set to: " + signaturePlaceholderData.getProfile());
-					requestedSignature.setSignatureProfileID(signaturePlaceholderData.getProfile());
-				}
-
-				tablePos = signaturePlaceholderData.getTablePos();
-				if (tablePos != null) {
-
-					SignatureProfileConfiguration signatureProfileConfiguration = pdfObject.getStatus()
-							.getSignatureProfileConfiguration(requestedSignature.getSignatureProfileID());
-
-					float minWidth = signatureProfileConfiguration.getMinWidth();
-
-					if(minWidth > 0) {
-						if (tablePos.getWidth() < minWidth) {
-							tablePos.width = minWidth;
-							logger.debug("Correcting placeholder with to minimum width {}", minWidth);
-						}
-					}
-					logger.debug("Placeholder Position set to: " + tablePos.toString());
-				}
-			}
-			SignatureProfileSettings signatureProfileSettings = TableFactory
-					.createProfile(requestedSignature.getSignatureProfileID(), pdfObject.getStatus().getSettings());
-            			
-			//Check if input document is PDF-A conform
-            if (signatureProfileSettings.isPDFA()) {
-                DataSource origDoc = pdfObject.getOriginalDocument();
-                InputStream stream = origDoc.getInputStream();
-                //Run PreflightParser for checking conformity//
-                //runPDFAPreflight(origDoc);
+          if (minWidth > 0) {
+            if (tablePos.getWidth() < minWidth) {
+              tablePos.width = minWidth;
+              logger.debug("Correcting placeholder with to minimum width {}", minWidth);
             }
-			ValueResolver resolver = new ValueResolver(requestedSignature, pdfObject.getStatus());
-
-			String signerName = resolver.resolve("SIG_SUBJECT", signatureProfileSettings.getValue("SIG_SUBJECT"),
-					signatureProfileSettings);
-
-			signature.setName(signerName);
-			signature.setSignDate(Calendar.getInstance());
-			String signerReason = signatureProfileSettings.getSigningReason();
-
-			if (signerReason == null) {
-				signerReason = "PAdES Signature";
-			}
-
-			signature.setReason(signerReason);
-			logger.debug("Signing reason: " + signerReason);
-
-			logger.debug("Signing @ " + signer.getSigningDate().getTime().toString());
-			// the signing date, needed for valid signature
-			// signature.setSignDate(signer.getSigningDate());
-
-			signer.setPDSignature(signature);
-
-			int signatureSize = 0x1000;
-			try {
-				String reservedSignatureSizeString = signatureProfileSettings.getValue(SIG_RESERVED_SIZE);
-				if (reservedSignatureSizeString != null) {
-					signatureSize = Integer.parseInt(reservedSignatureSizeString);
-				}
-				logger.debug("Reserving {} bytes for signature", signatureSize);
-			} catch (NumberFormatException e) {
-				logger.warn("Invalid configuration value: {} should be a number using 0x1000", SIG_RESERVED_SIZE);
-			}
-			options.setPreferredSignatureSize(signatureSize);
-
-            if(signatureProfileSettings.isPDFA() || signatureProfileSettings.isPDFA3()) {
-                pdfaVersion = getPDFAVersion(doc);
-                signatureProfileSettings.setPDFAVersion(pdfaVersion);
-            }
-
-			// Is visible Signature
-			if (requestedSignature.isVisual()) {
-				logger.info("Creating visual siganture block");
-
-				SignatureProfileConfiguration signatureProfileConfiguration = pdfObject.getStatus()
-						.getSignatureProfileConfiguration(requestedSignature.getSignatureProfileID());
+          }
+          logger.debug("Placeholder Position set to: " + tablePos.toString());
+        }
+      }
+      final SignatureProfileSettings signatureProfileSettings = TableFactory
+          .createProfile(requestedSignature.getSignatureProfileID(), pdfObject.getStatus().getSettings());
+
+      // Check if input document is PDF-A conform
+      if (signatureProfileSettings.isPDFA()) {
+        final DataSource origDoc = pdfObject.getOriginalDocument();
+        final InputStream stream = origDoc.getInputStream();
+        // Run PreflightParser for checking conformity//
+        // runPDFAPreflight(origDoc);
+      }
+      final ValueResolver resolver = new ValueResolver(requestedSignature, pdfObject.getStatus());
+
+      final String signerName = resolver.resolve("SIG_SUBJECT", signatureProfileSettings.getValue(
+          "SIG_SUBJECT"),
+          signatureProfileSettings);
+
+      signature.setName(signerName);
+      signature.setSignDate(Calendar.getInstance());
+      String signerReason = signatureProfileSettings.getSigningReason();
+
+      if (signerReason == null) {
+        signerReason = "PAdES Signature";
+      }
+
+      signature.setReason(signerReason);
+      logger.debug("Signing reason: " + signerReason);
+
+      logger.debug("Signing @ " + signer.getSigningDate().getTime().toString());
+      // the signing date, needed for valid signature
+      // signature.setSignDate(signer.getSigningDate());
+
+      signer.setPDSignature(signature);
+
+      int signatureSize = 0x1000;
+      try {
+        final String reservedSignatureSizeString = signatureProfileSettings.getValue(SIG_RESERVED_SIZE);
+        if (reservedSignatureSizeString != null) {
+          signatureSize = Integer.parseInt(reservedSignatureSizeString);
+        }
+        logger.debug("Reserving {} bytes for signature", signatureSize);
+      } catch (final NumberFormatException e) {
+        logger.warn("Invalid configuration value: {} should be a number using 0x1000", SIG_RESERVED_SIZE);
+      }
+      options.setPreferredSignatureSize(signatureSize);
+
+      if (signatureProfileSettings.isPDFA() || signatureProfileSettings.isPDFA3()) {
+        pdfaVersion = getPDFAVersion(doc);
+        signatureProfileSettings.setPDFAVersion(pdfaVersion);
+      }
+
+      // Is visible Signature
+      if (requestedSignature.isVisual()) {
+        logger.info("Creating visual siganture block");
+
+        final SignatureProfileConfiguration signatureProfileConfiguration = pdfObject.getStatus()
+            .getSignatureProfileConfiguration(requestedSignature.getSignatureProfileID());
+
+        if (tablePos == null) {
+          // ================================================================
+          // PositioningStage (visual) -> find position or use
+          // fixed
+          // position
+
+          final String posString = pdfObject.getStatus().getSignParamter().getSignaturePosition();
+
+          TablePos signaturePos = null;
+
+          final String signaturePosString = signatureProfileConfiguration.getDefaultPositioning();
+
+          if (signaturePosString != null) {
+            logger.debug("using signature Positioning: " + signaturePos);
+            signaturePos = new TablePos(signaturePosString);
+          }
+
+          logger.debug("using Positioning: " + posString);
+
+          if (posString != null) {
+            // Merge Signature Position
+            tablePos = new TablePos(posString, signaturePos);
+          } else {
+            // Fallback to signature Position!
+            tablePos = signaturePos;
+          }
+
+          if (tablePos == null) {
+            // Last Fallback default position
+            tablePos = new TablePos();
+          }
+        }
 
-				if (tablePos == null) {
-					// ================================================================
-					// PositioningStage (visual) -> find position or use
-					// fixed
-					// position
+        // Legacy Modes not supported with pdfbox2 anymore
+//				boolean legacy32Position = signatureProfileConfiguration.getLegacy32Positioning();
+//				boolean legacy40Position = signatureProfileConfiguration.getLegacy40Positioning();
 
-					String posString = pdfObject.getStatus().getSignParamter().getSignaturePosition();
+        // create Table describtion
+
+        final Table main = TableFactory.createSigTable(signatureProfileSettings, MAIN, pdfObject.getStatus(),
+            requestedSignature);
+
+        final IPDFStamper stamper = StamperFactory.createDefaultStamper(pdfObject.getStatus().getSettings());
+
+        final IPDFVisualObject visualObject = stamper.createVisualPDFObject(pdfObject, main);
+
+        /*
+         * PDDocument originalDocument = PDDocument .load(new
+         * ByteArrayInputStream(pdfObject.getStatus()
+         * .getPdfObject().getOriginalDocument()));
+         */
+
+        final PositioningInstruction positioningInstruction = Positioning.determineTablePositioning(tablePos,
+            "",
+            doc, visualObject, pdfObject.getStatus().getSettings());
+
+        logger.debug("Positioning: {}", positioningInstruction.toString());
+
+        if (!isAdobeSigForm) {
+          if (positioningInstruction.isMakeNewPage()) {
+            final int last = doc.getNumberOfPages() - 1;
+            final PDDocumentCatalog root = doc.getDocumentCatalog();
+            final PDPage lastPage = root.getPages().get(last);
+            root.getPages().getCOSObject().setNeedToBeUpdated(true);
+            final PDPage p = new PDPage(lastPage.getMediaBox());
+            p.setResources(new PDResources());
+            p.setRotation(lastPage.getRotation());
+            doc.addPage(p);
+          }
+
+          // handle rotated page
+          final int targetPageNumber = positioningInstruction.getPage();
+          logger.debug("Target Page: " + targetPageNumber);
+          final PDPage targetPage = doc.getPages().get(targetPageNumber - 1);
+          final int rot = targetPage.getRotation();
+          logger.debug("Page rotation: " + rot);
+          logger.debug("resulting Sign rotation: " + positioningInstruction.getRotation());
+
+          final SignaturePositionImpl position = new SignaturePositionImpl();
+          position.setX(positioningInstruction.getX());
+          position.setY(positioningInstruction.getY());
+          position.setPage(positioningInstruction.getPage());
+          position.setHeight(visualObject.getHeight());
+          position.setWidth(visualObject.getWidth());
+          requestedSignature.setSignaturePosition(position);
+        }
 
-					TablePos signaturePos = null;
+        properties = new PDFAsVisualSignatureProperties(pdfObject.getStatus().getSettings(), pdfObject,
+            (PdfBoxVisualObject) visualObject, positioningInstruction, signatureProfileSettings);
+
+        properties.buildSignature();
+
+        /*
+         * ByteArrayOutputStream sigbos = new ByteArrayOutputStream();
+         * sigbos.write(StreamUtils.inputStreamToByteArray (properties
+         * .getVisibleSignature())); sigbos.close();
+         */
+
+        /*
+         * if (signaturePlaceholderData != null) {
+         * 
+         * InputStream fis =
+         * PADESPDFBOXSigner.class.getResourceAsStream("/placeholder/empty.jpg");
+         * PDImageXObject img = JPEGFactory.createFromStream(doc, fis);
+         * 
+         * img.getCOSObject().setNeedToBeUpdated(true); // PDDocumentCatalog root =
+         * doc.getDocumentCatalog(); // PDPageNode rootPages = root.getPages(); //
+         * List<PDPage> kids = new ArrayList<PDPage>(); // rootPages.getAllKids(kids);
+         * int pageNumber = positioningInstruction.getPage(); PDPage page =
+         * doc.getPages().get(pageNumber - 1);
+         * 
+         * logger.info("Placeholder name: " +
+         * signaturePlaceholderData.getPlaceholderName()); COSDictionary
+         * xobjectsDictionary = (COSDictionary) page.getResources().getCOSObject()
+         * .getDictionaryObject(COSName.XOBJECT);
+         * 
+         * 
+         * xobjectsDictionary.setItem(signaturePlaceholderData.getPlaceholderName(),
+         * img); xobjectsDictionary.setNeedToBeUpdated(true);
+         * page.getResources().getCOSObject().setNeedToBeUpdated(true);
+         * logger.info("Placeholder name: " +
+         * signaturePlaceholderData.getPlaceholderName()); }
+         */
+
+        if (signatureProfileSettings.isPDFA() || signatureProfileSettings.isPDFA3()) {
+          final PDDocumentCatalog root = doc.getDocumentCatalog();
+          final COSBase base = root.getCOSObject().getItem(COSName.OUTPUT_INTENTS);
+
+          InputStream colorProfile = null;
+          // colorProfile = this.getClass().getResourceAsStream("/icm/sRGB.icm");
+          colorProfile = this.getClass().getResourceAsStream("/icm/sRGB Color Space Profile.icm");
+          // Set output intents for PDF/A conformity//
+          try {
+            final PDOutputIntent intent = new PDOutputIntent(doc, colorProfile);
+
+            intent.setInfo("sRGB IEC61966-2.1");
+            intent.setOutputCondition("sRGB IEC61966-2.1");
+            intent.setOutputConditionIdentifier("sRGB IEC61966-2.1");
+            intent.setRegistryName("http://www.color.org");
+            final List<PDOutputIntent> oi = new ArrayList<>();
+            oi.add(intent);
+            root.setOutputIntents(oi);
+            root.getCOSObject().setNeedToBeUpdated(true);
+
+            logger.info("added Output Intent");
+          } catch (final Throwable e) {
+            e.printStackTrace();
+            throw new PdfAsException("Failed to add Output Intent", e);
+          } finally {
+            IOUtils.closeQuietly(colorProfile);
+          }
+        }
+        options.setPage(positioningInstruction.getPage() - 1);
+        options.setVisualSignature(properties.getVisibleSignature());
+      }
 
-					String signaturePosString = signatureProfileConfiguration.getDefaultPositioning();
+      visualSignatureDocumentGuard = options.getVisualSignature();
 
-					if (signaturePosString != null) {
-						logger.debug("using signature Positioning: " + signaturePos);
-						signaturePos = new TablePos(signaturePosString);
-					}
+      doc.addSignature(signature, signer, options);
 
-					logger.debug("using Positioning: " + posString);
+      if (sigFieldName == null) {
+        sigFieldName = "PDF-AS Signatur";
+      }
+      final int count = PdfBoxUtils.countSignatures(doc, sigFieldName);
 
-					if (posString != null) {
-						// Merge Signature Position
-						tablePos = new TablePos(posString, signaturePos);
-					} else {
-						// Fallback to signature Position!
-						tablePos = signaturePos;
-					}
+      sigFieldName = sigFieldName + count;
 
-					if (tablePos == null) {
-						// Last Fallback default position
-						tablePos = new TablePos();
-					}
-				}
+      final PDAcroForm acroFormm = doc.getDocumentCatalog().getAcroForm();
 
-				//Legacy Modes not supported with pdfbox2 anymore
-//				boolean legacy32Position = signatureProfileConfiguration.getLegacy32Positioning();
-//				boolean legacy40Position = signatureProfileConfiguration.getLegacy40Positioning();
+      // PDStructureTreeRoot pdstRoot =
+      // doc.getDocumentCatalog().getStructureTreeRoot();
+      // COSDictionary dic =
+      // doc.getDocumentCatalog().getCOSDictionary();
+      // PDStructureElement el = new PDStructureElement("Widget",
+      // pdstRoot);
 
-				// create Table describtion
-
-
-				Table main = TableFactory.createSigTable(signatureProfileSettings, MAIN, pdfObject.getStatus(),
-						requestedSignature);
-
-				IPDFStamper stamper = StamperFactory.createDefaultStamper(pdfObject.getStatus().getSettings());
-
-				IPDFVisualObject visualObject = stamper.createVisualPDFObject(pdfObject, main);
-
-				/*
-				 * PDDocument originalDocument = PDDocument .load(new
-				 * ByteArrayInputStream(pdfObject.getStatus()
-				 * .getPdfObject().getOriginalDocument()));
-				 */
-
-				PositioningInstruction positioningInstruction = Positioning.determineTablePositioning(tablePos, "",
-						doc, visualObject, pdfObject.getStatus().getSettings());
-
-				logger.debug("Positioning: {}", positioningInstruction.toString());
-
-				if(!isAdobeSigForm)  {
-				if (positioningInstruction.isMakeNewPage()) {
-					int last = doc.getNumberOfPages() - 1;
-					PDDocumentCatalog root = doc.getDocumentCatalog();
-					PDPage lastPage = root.getPages().get(last);
-					root.getPages().getCOSObject().setNeedToBeUpdated(true);
-					PDPage p = new PDPage(lastPage.getMediaBox());
-					p.setResources(new PDResources());
-					p.setRotation(lastPage.getRotation());
-					doc.addPage(p);
-				}
-
-				// handle rotated page
-				int targetPageNumber = positioningInstruction.getPage();
-				logger.debug("Target Page: " + targetPageNumber);
-				PDPage targetPage = doc.getPages().get(targetPageNumber - 1);
-				int rot = targetPage.getRotation();
-				logger.debug("Page rotation: " + rot);
-				logger.debug("resulting Sign rotation: " + positioningInstruction.getRotation());
-
-				SignaturePositionImpl position = new SignaturePositionImpl();
-				position.setX(positioningInstruction.getX());
-				position.setY(positioningInstruction.getY());
-				position.setPage(positioningInstruction.getPage());
-				position.setHeight(visualObject.getHeight());
-				position.setWidth(visualObject.getWidth());
-				requestedSignature.setSignaturePosition(position);
-				}
-
-				properties = new PDFAsVisualSignatureProperties(pdfObject.getStatus().getSettings(), pdfObject,
-						(PdfBoxVisualObject) visualObject, positioningInstruction, signatureProfileSettings);
-
-				properties.buildSignature();
-
-				/*
-				 * ByteArrayOutputStream sigbos = new
-				 * ByteArrayOutputStream();
-				 * sigbos.write(StreamUtils.inputStreamToByteArray
-				 * (properties .getVisibleSignature())); sigbos.close();
-				 */
-
-				/*if (signaturePlaceholderData != null) {
-
-					InputStream fis = PADESPDFBOXSigner.class.getResourceAsStream("/placeholder/empty.jpg");
-					PDImageXObject img = JPEGFactory.createFromStream(doc, fis);
-
-					img.getCOSObject().setNeedToBeUpdated(true);
-					//							PDDocumentCatalog root = doc.getDocumentCatalog();
-					//							PDPageNode rootPages = root.getPages();
-					//							List<PDPage> kids = new ArrayList<PDPage>();
-					//							rootPages.getAllKids(kids);
-					int pageNumber = positioningInstruction.getPage();
-					PDPage page = doc.getPages().get(pageNumber - 1);
-
-					logger.info("Placeholder name: " + signaturePlaceholderData.getPlaceholderName());
-					COSDictionary xobjectsDictionary = (COSDictionary) page.getResources().getCOSObject()
-							.getDictionaryObject(COSName.XOBJECT);
-
-
-					xobjectsDictionary.setItem(signaturePlaceholderData.getPlaceholderName(), img);
-					xobjectsDictionary.setNeedToBeUpdated(true);
-					page.getResources().getCOSObject().setNeedToBeUpdated(true);
-					logger.info("Placeholder name: " + signaturePlaceholderData.getPlaceholderName());
-				}*/
-
-				if (signatureProfileSettings.isPDFA() || signatureProfileSettings.isPDFA3()) {
-                    PDDocumentCatalog root = doc.getDocumentCatalog();
-                    COSBase base = root.getCOSObject().getItem(COSName.OUTPUT_INTENTS);
-
-                    InputStream colorProfile = null;
-                    //colorProfile = this.getClass().getResourceAsStream("/icm/sRGB.icm");
-					colorProfile = this.getClass().getResourceAsStream("/icm/sRGB Color Space Profile.icm");
-                     //Set output intents for PDF/A conformity//
-                            try {
-                                PDOutputIntent intent = new PDOutputIntent(doc, colorProfile);
-
-                                intent.setInfo("sRGB IEC61966-2.1");
-                                intent.setOutputCondition("sRGB IEC61966-2.1");
-                                intent.setOutputConditionIdentifier("sRGB IEC61966-2.1");
-                                intent.setRegistryName("http://www.color.org");
-                                List<PDOutputIntent> oi = new ArrayList<PDOutputIntent>();
-                                oi.add(intent);
-                                root.setOutputIntents(oi);
-                                root.getCOSObject().setNeedToBeUpdated(true);
-
-                                logger.info("added Output Intent");
-                            } catch (Throwable e) {
-                                e.printStackTrace();
-                                throw new PdfAsException("Failed to add Output Intent", e);
-                            }
-                         finally {
-                            IOUtils.closeQuietly(colorProfile);
-                        }
-                    }
-                options.setPage(positioningInstruction.getPage()-1);
-                options.setVisualSignature(properties.getVisibleSignature());
-            }
+      // this is not used for Adobe signature fields
+      if (!isAdobeSigForm) {
+        PDSignatureField signatureField = null;
+        if (acroFormm != null) {
+          @SuppressWarnings("unchecked")
+          final List<PDField> fields = acroFormm.getFields();
 
-			visualSignatureDocumentGuard = options.getVisualSignature();
-
-			doc.addSignature(signature, signer, options);
-
-			if (sigFieldName == null) {
-				sigFieldName = "PDF-AS Signatur";
-			}
-			int count = PdfBoxUtils.countSignatures(doc, sigFieldName);
-
-			sigFieldName = sigFieldName + count;
-
-			PDAcroForm acroFormm = doc.getDocumentCatalog().getAcroForm();
-
-			// PDStructureTreeRoot pdstRoot =
-			// doc.getDocumentCatalog().getStructureTreeRoot();
-			// COSDictionary dic =
-			// doc.getDocumentCatalog().getCOSDictionary();
-			// PDStructureElement el = new PDStructureElement("Widget",
-			// pdstRoot);
-
-			//this is not used for Adobe signature fields
-			if(!isAdobeSigForm) {
-				PDSignatureField signatureField = null;
-			if (acroFormm != null) {
-				@SuppressWarnings("unchecked")
-				List<PDField> fields = acroFormm.getFields();
-
-				if (fields != null) {
-					for (PDField pdField : fields) {
-						if (pdField != null) {
-							if (pdField instanceof PDSignatureField) {
-								PDSignatureField tmpSigField = (PDSignatureField) pdField;
-
-								if (tmpSigField.getSignature() != null
-										&& tmpSigField.getSignature().getCOSObject() != null) {
-									if (tmpSigField.getSignature().getCOSObject()
-											.equals(signature.getCOSObject())) {
-										signatureField = (PDSignatureField) pdField;
-
-									}
-								}
-							}
-						}
-					}
-				} else {
-					logger.warn("Failed to name Signature Field! [Cannot find Field list in acroForm!]");
-				}
-
-				if (signatureField != null) {
-					signatureField.setPartialName(sigFieldName);
-				}
-				if (properties != null) {
-					signatureField.setAlternateFieldName(properties.getAlternativeTableCaption());
-				} else {
-					signatureField.setAlternateFieldName(sigFieldName);
-				}
-			} else {
-				logger.warn("Failed to name Signature Field! [Cannot find acroForm!]");
-			}
-			}
-
-			PDSignatureField signatureField = null;
-			PDAcroForm acroForm = doc.getDocumentCatalog().getAcroForm();
-			if (acroForm != null) {
-				signatureField = (PDSignatureField) acroForm.getField(sigFieldName);
-			}
-
-			// PDF-UA
-			logger.info("Adding pdf/ua content.");
-			try {
-				PDDocumentCatalog root = doc.getDocumentCatalog();
-				PDStructureTreeRoot structureTreeRoot = root.getStructureTreeRoot();
-				if (structureTreeRoot != null) {
-					logger.info("Tree Root: {}", structureTreeRoot.toString());
-					List<Object> kids = structureTreeRoot.getKids();
-
-					if (kids == null) {
-						logger.info("No kid-elements in structure tree Root, maybe not PDF/UA document");
-					}
-
-					PDStructureElement docElement = null;
-					for (Object k : kids) {
-						if (k instanceof PDStructureElement) {
-							docElement = (PDStructureElement) k;
-							break;
-
-						}
-					}
-					
-					PDStructureElement sigBlock = new PDStructureElement("Form", docElement);
-
-					// create object dictionary and add as child element
-					COSDictionary objectDic = new COSDictionary();
-					objectDic.setName("Type", "OBJR");
-										
-					objectDic.setItem("Pg", signatureField.getWidget().getPage());
-					objectDic.setItem("Obj", signatureField.getWidget());
-
-					List<Object> l = new ArrayList<Object>();
-					l.add(objectDic);
-					sigBlock.setKids(l);
-					sigBlock.setPage(signatureField.getWidget().getPage());
-
-
-					sigBlock.setTitle("Signature Table");
-					sigBlock.setParent(docElement);
-					docElement.appendKid(sigBlock);
-
-					// Create and add Attribute dictionary to mitigate PAC
-					// warning
-					COSDictionary sigBlockDic = (COSDictionary) sigBlock.getCOSObject();
-					COSDictionary sub = new COSDictionary();
-
-					sub.setName("O", "Layout");
-					sub.setName("Placement", "Block");
-					sigBlockDic.setItem(COSName.A, sub);
-					sigBlockDic.setNeedToBeUpdated(true);
-
-					// Modify number tree
-					PDNumberTreeNode ntn = structureTreeRoot.getParentTree();
-					if (ntn == null) {
-						ntn = new PDNumberTreeNode(objectDic, null);
-						logger.info("No number-tree-node found!");
-					}
-
-					COSArray ntnKids = (COSArray) ntn.getCOSObject().getDictionaryObject(COSName.KIDS);
-					COSArray ntnNumbers = (COSArray) ntn.getCOSObject().getDictionaryObject(COSName.NUMS);
-					
-					int parentTreeNextKey = getParentTreeNextKey(structureTreeRoot);
-					
-					if(ntnNumbers == null && ntnKids != null){//no number array, so continue with the kids array																								
-						//create dictionary with limits and nums array
-						COSDictionary pTreeEntry = new COSDictionary();
-						COSArray limitsArray = new COSArray();
-						//limits for exact one entry
-						limitsArray.add(COSInteger.get(parentTreeNextKey));
-						limitsArray.add(COSInteger.get(parentTreeNextKey));
-
-						COSArray numsArray = new COSArray();
-						numsArray.add(COSInteger.get(parentTreeNextKey));
-						numsArray.add(sigBlock);
-
-						pTreeEntry.setItem(COSName.NUMS, numsArray);
-						pTreeEntry.setItem(COSName.LIMITS, limitsArray);
-
-						PDNumberTreeNode newKidsElement = new PDNumberTreeNode(pTreeEntry, PDNumberTreeNode.class);
-
-						ntnKids.add(newKidsElement);
-						ntnKids.setNeedToBeUpdated(true);
-
-
-					}else if(ntnNumbers != null && ntnKids == null){
-
-						int arrindex = ntnNumbers.size();
-
-						ntnNumbers.add(arrindex, COSInteger.get(parentTreeNextKey));
-						ntnNumbers.add(arrindex + 1, sigBlock.getCOSObject());
-
-						ntnNumbers.setNeedToBeUpdated(true);
-
-						structureTreeRoot.setParentTree(ntn);
-
-					}else if(ntnNumbers == null && ntnKids == null){
-						//document is not pdfua conform before signature creation
-						throw new PdfAsException("error.pdf.sig.pdfua.1");
-					}else{
-						//this is not allowed
-						throw new PdfAsException("error.pdf.sig.pdfua.1");
-					}
-
-					// set StructureParent for signature field annotation
-					signatureField.getWidget().setStructParent(parentTreeNextKey);
-
-					//Increase the next Key value in the structure tree root
-					structureTreeRoot.setParentTreeNextKey(parentTreeNextKey+1);
-
-					// add the Tabs /S Element for Tabbing through annots
-					PDPage p = signatureField.getWidget().getPage();
-					p.getCOSObject().setName("Tabs", "S");
-					p.getCOSObject().setNeedToBeUpdated(true);
-
-					//check alternative signature field name
-					if (signatureField != null) {
-						if(signatureField.getAlternateFieldName().equals(""))
-							signatureField.setAlternateFieldName(sigFieldName);
-					}
-
-					ntn.getCOSObject().setNeedToBeUpdated(true);
-					sigBlock.getCOSObject().setNeedToBeUpdated(true);
-					structureTreeRoot.getCOSObject().setNeedToBeUpdated(true);
-					objectDic.setNeedToBeUpdated(true);
-					docElement.getCOSObject().setNeedToBeUpdated(true);
-				}
-			} catch (Throwable e) {
-				if (signatureProfileSettings.isPDFUA() == true) {
-					logger.error("Could not create PDF-UA conform document!");
-					throw new PdfAsException("error.pdf.sig.pdfua.1", e);
-				} else {
-					logger.info("Could not create PDF-UA conform signature");
-				}
-			}
-
-            try {
-                ByteArrayOutputStream bos = new ByteArrayOutputStream();
-                        synchronized (doc) {
-                    doc.saveIncremental(bos);
-                            byte[] outputDocument = bos.toByteArray();
-                            pdfObject.setSignedDocument(outputDocument);
-                }
-                        /* Check if resulting pdf is PDF-A conform */                                                
-                    if (signatureProfileSettings.isPDFA()) {
-                        runPDFAPreflight(new ByteArrayDataSource(pdfObject.getSignedDocument()));
-                    }
+          if (fields != null) {
+            for (final PDField pdField : fields) {
+              if (pdField != null) {
+                if (pdField instanceof PDSignatureField) {
+                  final PDSignatureField tmpSigField = (PDSignatureField) pdField;
 
-            } catch (IOException e1) {
-                e1.printStackTrace();
-            }
+                  if (tmpSigField.getSignature() != null
+                      && tmpSigField.getSignature().getCOSObject() != null) {
+                    if (tmpSigField.getSignature().getCOSObject()
+                        .equals(signature.getCOSObject())) {
+                      signatureField = (PDSignatureField) pdField;
 
-         finally {
-                if (options != null) {
-                    if (options.getVisualSignature() != null) {
-                        options.getVisualSignature().close();
                     }
+                  }
                 }
+              }
             }
+          } else {
+            logger.warn("Failed to name Signature Field! [Cannot find Field list in acroForm!]");
+          }
+
+          if (signatureField != null) {
+            signatureField.setPartialName(sigFieldName);
+          }
+          if (properties != null) {
+            signatureField.setAlternateFieldName(properties.getAlternativeTableCaption());
+          } else {
+            signatureField.setAlternateFieldName(sigFieldName);
+          }
+        } else {
+          logger.warn("Failed to name Signature Field! [Cannot find acroForm!]");
+        }
+      }
+
+      PDSignatureField signatureField = null;
+      final PDAcroForm acroForm = doc.getDocumentCatalog().getAcroForm();
+      if (acroForm != null) {
+        signatureField = (PDSignatureField) acroForm.getField(sigFieldName);
+      }
+
+      // PDF-UA
+      logger.info("Adding pdf/ua content.");
+      try {
+        final PDDocumentCatalog root = doc.getDocumentCatalog();
+        final PDStructureTreeRoot structureTreeRoot = root.getStructureTreeRoot();
+        if (structureTreeRoot != null) {
+          logger.info("Tree Root: {}", structureTreeRoot.toString());
+          final List<Object> kids = structureTreeRoot.getKids();
+
+          if (kids == null) {
+            logger.info("No kid-elements in structure tree Root, maybe not PDF/UA document");
+          }
+
+          PDStructureElement docElement = null;
+          for (final Object k : kids) {
+            if (k instanceof PDStructureElement) {
+              docElement = (PDStructureElement) k;
+              break;
 
-            System.gc();
-        } catch (IOException e) {
-            logger.warn(MessageResolver.resolveMessage("error.pdf.sig.01"), e);
-            throw new PdfAsException("error.pdf.sig.01", e);
-		} finally {
-            if (doc != null) {
-                try {
-                    doc.close();
-					//SignaturePlaceholderExtractor.getPlaceholders().clear();
-                } catch (IOException e) {
-                    logger.debug("Failed to close COS Doc!", e);
-                    // Ignore
-                }
-            }
-			logger.debug("Signature done!");
-		}
-	}
-
-    private int getParentTreeNextKey(PDStructureTreeRoot structureTreeRoot) throws IOException {
-    	int nextKey = structureTreeRoot.getParentTreeNextKey();
-    	if (nextKey < 0) {
-    		Map<Integer, COSObjectable> destNumberTreeAsMap = getNumberTreeAsMap(structureTreeRoot.getParentTree());
-    		if (destNumberTreeAsMap.isEmpty()) {
-    			nextKey = 0;
-                
-            } else {
-            	nextKey = Collections.max(destNumberTreeAsMap.keySet()) + 1;
-            	
-            }    		
-    	} 
-    	    	
-		return nextKey;
-	}
-
-	/**
-     * Check via PreFlightParser if PDF-Document is a valid PDFA1
-     * @param signedDocument: signed Document
-     * @throws PdfAsException
-     */
-    private void runPDFAPreflight(final DataSource signedDocument) throws PdfAsException {
-        PreflightDocument document = null;
-        ValidationResult result = null;
-        try {
-            PreflightParser parser = new PreflightParser(signedDocument);
-            //
-            // parser.parse(Format.PDF_A1B);
-            parser.parse();
-            document = parser.getPreflightDocument();
-            document.validate();
-
-            document.close();
-            result = document.getResult();
-            logger.info("PDF-A Validation Result: " + result.isValid());
-
-            if (result.getErrorsList().size() > 0) {
-                logger.error("The following validation errors occured for PDF-A validation");
             }
+          }
 
-            for (ValidationResult.ValidationError ve : result.getErrorsList()) {
-                logger.error("\t" + ve.getErrorCode() + ": " + ve.getDetails());
-            }
+          final PDStructureElement sigBlock = new PDStructureElement("Form", docElement);
 
-            if (!result.isValid()) {
-                logger.info("The file is not a valid PDF-A document");
-            }
+          // create object dictionary and add as child element
+          final COSDictionary objectDic = new COSDictionary();
+          objectDic.setName("Type", "OBJR");
 
-        } catch (SyntaxValidationException e) {
-            logger.error("The file is syntactically invalid.", e);
-            throw new PdfAsException("Resulting PDF Document is syntactically invalid.");
-        } catch (ValidationException e) {
-            logger.error("The file is not a valid PDF-A document.", e);
-        } catch (IOException e) {
-            logger.error("An IOException (" + e.getMessage()
-                    + ") occurred, while validating the PDF-A conformance", e);
-            throw new PdfAsException("Failed validating PDF Document IOException.");
-        } catch (RuntimeException e) {
-            logger.debug("An RuntimeException (" + e.getMessage()
-                    + ") occurred, while validating the PDF-A conformance", e);
-            throw new PdfAsException("Failed validating PDF Document RuntimeException.");
-        } finally {
-            if (document != null) {
-                IOUtils.closeQuietly(document);
-            }
-        }
-    }
+          objectDic.setItem("Pg", signatureField.getWidget().getPage());
+          objectDic.setItem("Obj", signatureField.getWidget());
 
-    @Override
-    public PDFObject buildPDFObject(OperationStatus operationStatus) {
-        return new PDFBOXObject(operationStatus);
-    }
+          final List<Object> l = new ArrayList<>();
+          l.add(objectDic);
+          sigBlock.setKids(l);
+          sigBlock.setPage(signatureField.getWidget().getPage());
 
-    @Override
-    public PDFASSignatureInterface buildSignaturInterface(IPlainSigner signer, SignParameter parameters,
-                                                          RequestedSignature requestedSignature) {
-        return new PdfboxSignerWrapper(signer, parameters, requestedSignature);
-    }
+          sigBlock.setTitle("Signature Table");
+          sigBlock.setParent(docElement);
+          docElement.appendKid(sigBlock);
 
-    @Override
-    public PDFASSignatureExtractor buildBlindSignaturInterface(X509Certificate certificate, String filter, String subfilter, Calendar date) {
-        return new SignatureDataExtractor(certificate, filter, subfilter, date);
-    }
+          // Create and add Attribute dictionary to mitigate PAC
+          // warning
+          final COSDictionary sigBlockDic = sigBlock.getCOSObject();
+          final COSDictionary sub = new COSDictionary();
 
-    @Override
-    public void checkPDFPermissions(PDFObject genericPdfObject) throws PdfAsException {
-        if (!(genericPdfObject instanceof PDFBOXObject)) {
-            // tODO:
-            throw new PdfAsException();
-        }
+          sub.setName("O", "Layout");
+          sub.setName("Placement", "Block");
+          sigBlockDic.setItem(COSName.A, sub);
+          sigBlockDic.setNeedToBeUpdated(true);
 
-        PDFBOXObject pdfObject = (PDFBOXObject) genericPdfObject;
-        PdfBoxUtils.checkPDFPermissions(pdfObject.getDocument());
-    }
+          // Modify number tree
+          PDNumberTreeNode ntn = structureTreeRoot.getParentTree();
+          if (ntn == null) {
+            ntn = new PDNumberTreeNode(objectDic, null);
+            logger.info("No number-tree-node found!");
+          }
 
-    @Override
-    public byte[] rewritePlainSignature(byte[] plainSignature) {
-        String signature = new COSString(plainSignature).toHexString();
-        byte[] pdfSignature = signature.getBytes();
-        return pdfSignature;
-    }
+          final COSArray ntnKids = (COSArray) ntn.getCOSObject().getDictionaryObject(COSName.KIDS);
+          final COSArray ntnNumbers = (COSArray) ntn.getCOSObject().getDictionaryObject(COSName.NUMS);
 
-    @Override
-    public Image generateVisibleSignaturePreview(SignParameter parameter, java.security.cert.X509Certificate cert,
-                                                 int resolution, OperationStatus status, RequestedSignature requestedSignature) throws PDFASError {
-        try {
+          final int parentTreeNextKey = getParentTreeNextKey(structureTreeRoot);
 
-            PDFBOXObject pdfObject = (PDFBOXObject) status.getPdfObject();
-            PDDocument origDoc = new PDDocument();
+          if (ntnNumbers == null && ntnKids != null) {// no number array, so continue with the kids array
+            // create dictionary with limits and nums array
+            final COSDictionary pTreeEntry = new COSDictionary();
+            final COSArray limitsArray = new COSArray();
+            // limits for exact one entry
+            limitsArray.add(COSInteger.get(parentTreeNextKey));
+            limitsArray.add(COSInteger.get(parentTreeNextKey));
 
-            origDoc.addPage(new PDPage(PDRectangle.A4));
-            ByteArrayOutputStream baos = new ByteArrayOutputStream();
-            origDoc.save(baos);
-            baos.close();
+            final COSArray numsArray = new COSArray();
+            numsArray.add(COSInteger.get(parentTreeNextKey));
+            numsArray.add(sigBlock);
 
-            pdfObject.setOriginalDocument(new ByteArrayDataSource(baos.toByteArray()));
+            pTreeEntry.setItem(COSName.NUMS, numsArray);
+            pTreeEntry.setItem(COSName.LIMITS, limitsArray);
 
-            SignatureProfileSettings signatureProfileSettings = TableFactory
-                    .createProfile(requestedSignature.getSignatureProfileID(), pdfObject.getStatus().getSettings());
+            final PDNumberTreeNode newKidsElement = new PDNumberTreeNode(pTreeEntry, PDNumberTreeNode.class);
 
-            // create Table describtion
-            Table main = TableFactory.createSigTable(signatureProfileSettings, MAIN, pdfObject.getStatus(),
-                    requestedSignature);
+            ntnKids.add(newKidsElement);
+            ntnKids.setNeedToBeUpdated(true);
 
-            IPDFStamper stamper = StamperFactory.createDefaultStamper(pdfObject.getStatus().getSettings());
+          } else if (ntnNumbers != null && ntnKids == null) {
 
-            IPDFVisualObject visualObject = stamper.createVisualPDFObject(pdfObject, main);
+            final int arrindex = ntnNumbers.size();
 
-            SignatureProfileConfiguration signatureProfileConfiguration = pdfObject.getStatus()
-                    .getSignatureProfileConfiguration(requestedSignature.getSignatureProfileID());
+            ntnNumbers.add(arrindex, COSInteger.get(parentTreeNextKey));
+            ntnNumbers.add(arrindex + 1, sigBlock.getCOSObject());
 
-            String signaturePosString = signatureProfileConfiguration.getDefaultPositioning();
-            PositioningInstruction positioningInstruction;
-            if (signaturePosString != null) {
-                positioningInstruction = Positioning.determineTablePositioning(new TablePos(signaturePosString), "",
-                        origDoc, visualObject, pdfObject.getStatus().getSettings());
-            } else {
-                positioningInstruction = Positioning.determineTablePositioning(new TablePos(), "", origDoc,
-                        visualObject, pdfObject.getStatus().getSettings());
-            }
+            ntnNumbers.setNeedToBeUpdated(true);
 
-            origDoc.close();
+            structureTreeRoot.setParentTree(ntn);
 
-            SignaturePositionImpl position = new SignaturePositionImpl();
-            position.setX(positioningInstruction.getX());
-            position.setY(positioningInstruction.getY());
-            position.setPage(positioningInstruction.getPage());
-            position.setHeight(visualObject.getHeight());
-            position.setWidth(visualObject.getWidth());
+          } else if (ntnNumbers == null && ntnKids == null) {
+            // document is not pdfua conform before signature creation
+            throw new PdfAsException("error.pdf.sig.pdfua.1");
+          } else {
+            // this is not allowed
+            throw new PdfAsException("error.pdf.sig.pdfua.1");
+          }
 
-            requestedSignature.setSignaturePosition(position);
+          // set StructureParent for signature field annotation
+          signatureField.getWidget().setStructParent(parentTreeNextKey);
 
-            PDFAsVisualSignatureProperties properties = new PDFAsVisualSignatureProperties(
-                    pdfObject.getStatus().getSettings(), pdfObject, (PdfBoxVisualObject) visualObject,
-                    positioningInstruction, signatureProfileSettings);
+          // Increase the next Key value in the structure tree root
+          structureTreeRoot.setParentTreeNextKey(parentTreeNextKey + 1);
 
-            properties.buildSignature();
-            PDDocument visualDoc;
-            synchronized (PDDocument.class) {
-                visualDoc = PDDocument.load(properties.getVisibleSignature());
-            }
-            // PDPageable pageable = new PDPageable(visualDoc);
+          // add the Tabs /S Element for Tabbing through annots
+          final PDPage p = signatureField.getWidget().getPage();
+          p.getCOSObject().setName("Tabs", "S");
+          p.getCOSObject().setNeedToBeUpdated(true);
 
-            PDPage firstPage = visualDoc.getDocumentCatalog().getPages().get(0);
+          // check alternative signature field name
+          if (signatureField != null) {
+            if (signatureField.getAlternateFieldName().equals("")) {
+              signatureField.setAlternateFieldName(sigFieldName);
+            }
+          }
 
-            float stdRes = 72;
-            float targetRes = resolution;
-            float factor = targetRes / stdRes;
+          ntn.getCOSObject().setNeedToBeUpdated(true);
+          sigBlock.getCOSObject().setNeedToBeUpdated(true);
+          structureTreeRoot.getCOSObject().setNeedToBeUpdated(true);
+          objectDic.setNeedToBeUpdated(true);
+          docElement.getCOSObject().setNeedToBeUpdated(true);
+        }
+      } catch (final Throwable e) {
+        if (signatureProfileSettings.isPDFUA() == true) {
+          logger.error("Could not create PDF-UA conform document!");
+          throw new PdfAsException("error.pdf.sig.pdfua.1", e);
+        } else {
+          logger.info("Could not create PDF-UA conform signature");
+        }
+      }
+
+      try {
+        final ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        synchronized (doc) {
+          doc.saveIncremental(bos);
+          final byte[] outputDocument = bos.toByteArray();
+          pdfObject.setSignedDocument(outputDocument);
+        }
+        /* Check if resulting pdf is PDF-A conform */
+        if (signatureProfileSettings.isPDFA()) {
+          runPDFAPreflight(new ByteArrayDataSource(pdfObject.getSignedDocument()));
+        }
 
+      } catch (final IOException e1) {
+        e1.printStackTrace();
+      }
 
-            int targetPageNumber = 0;//TODO: is this always the case
-            PDFRenderer pdfRenderer = new PDFRenderer(visualDoc);
-            BufferedImage outputImage = pdfRenderer.renderImageWithDPI(targetPageNumber, targetRes, ImageType.ARGB);
+      finally {
+        if (options != null) {
+          if (options.getVisualSignature() != null) {
+            options.getVisualSignature().close();
+          }
+        }
+      }
+
+      System.gc();
+      logger.debug("Signature done!");
+      
+    } catch (final IOException e) {
+      logger.warn(MessageResolver.resolveMessage("error.pdf.sig.01"), e);
+      throw new PdfAsException("error.pdf.sig.01", e);
+    
+    } finally {
+      if (doc != null) {
+        try {
+          doc.close();
+          // SignaturePlaceholderExtractor.getPlaceholders().clear();
+        } catch (final IOException e) {
+          logger.debug("Failed to close COS Doc!", e);
+          // Ignore
+        }
+      }
+    }
+  }
 
-            //BufferedImage outputImage = firstPage.convertToImage(BufferedImage.TYPE_4BYTE_ABGR, (int) targetRes);
+  private int getParentTreeNextKey(PDStructureTreeRoot structureTreeRoot) throws IOException {
+    int nextKey = structureTreeRoot.getParentTreeNextKey();
+    if (nextKey < 0) {
+      final Map<Integer, COSObjectable> destNumberTreeAsMap = getNumberTreeAsMap(structureTreeRoot
+          .getParentTree());
+      if (destNumberTreeAsMap.isEmpty()) {
+        nextKey = 0;
 
-            BufferedImage cutOut = new BufferedImage((int) (position.getWidth() * factor),
-                    (int) (position.getHeight() * factor), BufferedImage.TYPE_4BYTE_ABGR);
+      } else {
+        nextKey = Collections.max(destNumberTreeAsMap.keySet()) + 1;
 
-            Graphics2D graphics = (Graphics2D) cutOut.getGraphics();
+      }
+    }
 
-            graphics.drawImage(outputImage, 0, 0, cutOut.getWidth(), cutOut.getHeight(), (int) (1 * factor),
-                    (int) (outputImage.getHeight() - ((position.getHeight() + 1) * factor)),
-                    (int) ((1 + position.getWidth()) * factor), (int) (outputImage.getHeight()
-                            - ((position.getHeight() + 1) * factor) + (position.getHeight() * factor)),
-                    null);
-            return cutOut;
-        } catch (PdfAsException e) {
-            logger.warn("PDF-AS  Exception", e);
-            throw ErrorExtractor.searchPdfAsError(e, status);
-        } catch (Throwable e) {
-            logger.warn("Unexpected Throwable  Exception", e);
-            throw ErrorExtractor.searchPdfAsError(e, status);
-        }
+    return nextKey;
+  }
+
+  /**
+   * Check via PreFlightParser if PDF-Document is a valid PDFA1
+   *
+   * @param signedDocument: signed Document
+   * @throws PdfAsException
+   */
+  private void runPDFAPreflight(final DataSource signedDocument) throws PdfAsException {
+    PreflightDocument document = null;
+    ValidationResult result = null;
+    try {
+      final PreflightParser parser = new PreflightParser(signedDocument);
+      //
+      // parser.parse(Format.PDF_A1B);
+      parser.parse();
+      document = parser.getPreflightDocument();
+      document.validate();
+
+      document.close();
+      result = document.getResult();
+      logger.info("PDF-A Validation Result: " + result.isValid());
+
+      if (result.getErrorsList().size() > 0) {
+        logger.error("The following validation errors occured for PDF-A validation");
+      }
+
+      for (final ValidationResult.ValidationError ve : result.getErrorsList()) {
+        logger.error("\t" + ve.getErrorCode() + ": " + ve.getDetails());
+      }
+
+      if (!result.isValid()) {
+        logger.info("The file is not a valid PDF-A document");
+      }
+
+    } catch (final SyntaxValidationException e) {
+      logger.error("The file is syntactically invalid.", e);
+      throw new PdfAsException("Resulting PDF Document is syntactically invalid.");
+    } catch (final ValidationException e) {
+      logger.error("The file is not a valid PDF-A document.", e);
+    } catch (final IOException e) {
+      logger.error("An IOException (" + e.getMessage()
+          + ") occurred, while validating the PDF-A conformance", e);
+      throw new PdfAsException("Failed validating PDF Document IOException.");
+    } catch (final RuntimeException e) {
+      logger.debug("An RuntimeException (" + e.getMessage()
+          + ") occurred, while validating the PDF-A conformance", e);
+      throw new PdfAsException("Failed validating PDF Document RuntimeException.");
+    } finally {
+      if (document != null) {
+        IOUtils.closeQuietly(document);
+      }
+    }
+  }
+
+  @Override
+  public PDFObject buildPDFObject(OperationStatus operationStatus) {
+    return new PDFBOXObject(operationStatus);
+  }
+
+  @Override
+  public PDFASSignatureInterface buildSignaturInterface(IPlainSigner signer, SignParameter parameters,
+      RequestedSignature requestedSignature) {
+    return new PdfboxSignerWrapper(signer, parameters, requestedSignature);
+  }
+
+  @Override
+  public PDFASSignatureExtractor buildBlindSignaturInterface(X509Certificate certificate, String filter,
+      String subfilter, Calendar date) {
+    return new SignatureDataExtractor(certificate, filter, subfilter, date);
+  }
+
+  @Override
+  public void checkPDFPermissions(PDFObject genericPdfObject) throws PdfAsException {
+    if (!(genericPdfObject instanceof PDFBOXObject)) {
+      // tODO:
+      throw new PdfAsException();
     }
 
-    private String getPDFAVersion(PDDocument doc) {
-        try {
-            PDDocumentCatalog cat = doc.getDocumentCatalog();
-            PDMetadata metadata = cat.getMetadata();
-
-            if (metadata != null) {
-                DomXmpParser xmpParser = new DomXmpParser();
-                XMPMetadata xmpMetadata = xmpParser.parse(metadata.exportXMPMetadata());
-                if (xmpMetadata != null) {
-                    PDFAIdentificationSchema pdfaIdentificationSchema = xmpMetadata.getPDFIdentificationSchema();
-                    if (pdfaIdentificationSchema != null) {
-                        Integer pdfaversion = pdfaIdentificationSchema.getPart();
-                        String conformance = pdfaIdentificationSchema.getConformance();
-                        logger.info("Detected PDF/A Version: {} - {}", pdfaversion, conformance);
-
-                        if (pdfaversion != null) {
-                            return String.valueOf(pdfaversion);
-                        }
-                    }
-                }
+    final PDFBOXObject pdfObject = (PDFBOXObject) genericPdfObject;
+    PdfBoxUtils.checkPDFPermissions(pdfObject.getDocument());
+  }
+
+  @Override
+  public byte[] rewritePlainSignature(byte[] plainSignature) {
+    final String signature = new COSString(plainSignature).toHexString();
+    final byte[] pdfSignature = signature.getBytes();
+    return pdfSignature;
+  }
+
+  @Override
+  public Image generateVisibleSignaturePreview(SignParameter parameter,
+      java.security.cert.X509Certificate cert,
+      int resolution, OperationStatus status, RequestedSignature requestedSignature) throws PDFASError {
+    try {
+
+      final PDFBOXObject pdfObject = (PDFBOXObject) status.getPdfObject();
+      final PDDocument origDoc = new PDDocument();
+
+      origDoc.addPage(new PDPage(PDRectangle.A4));
+      final ByteArrayOutputStream baos = new ByteArrayOutputStream();
+      origDoc.save(baos);
+      baos.close();
+
+      pdfObject.setOriginalDocument(new ByteArrayDataSource(baos.toByteArray()));
+
+      final SignatureProfileSettings signatureProfileSettings = TableFactory
+          .createProfile(requestedSignature.getSignatureProfileID(), pdfObject.getStatus().getSettings());
+
+      // create Table describtion
+      final Table main = TableFactory.createSigTable(signatureProfileSettings, MAIN, pdfObject.getStatus(),
+          requestedSignature);
+
+      final IPDFStamper stamper = StamperFactory.createDefaultStamper(pdfObject.getStatus().getSettings());
+
+      final IPDFVisualObject visualObject = stamper.createVisualPDFObject(pdfObject, main);
+
+      final SignatureProfileConfiguration signatureProfileConfiguration = pdfObject.getStatus()
+          .getSignatureProfileConfiguration(requestedSignature.getSignatureProfileID());
+
+      final String signaturePosString = signatureProfileConfiguration.getDefaultPositioning();
+      PositioningInstruction positioningInstruction;
+      if (signaturePosString != null) {
+        positioningInstruction = Positioning.determineTablePositioning(new TablePos(signaturePosString), "",
+            origDoc, visualObject, pdfObject.getStatus().getSettings());
+      } else {
+        positioningInstruction = Positioning.determineTablePositioning(new TablePos(), "", origDoc,
+            visualObject, pdfObject.getStatus().getSettings());
+      }
+
+      origDoc.close();
+
+      final SignaturePositionImpl position = new SignaturePositionImpl();
+      position.setX(positioningInstruction.getX());
+      position.setY(positioningInstruction.getY());
+      position.setPage(positioningInstruction.getPage());
+      position.setHeight(visualObject.getHeight());
+      position.setWidth(visualObject.getWidth());
+
+      requestedSignature.setSignaturePosition(position);
+
+      final PDFAsVisualSignatureProperties properties = new PDFAsVisualSignatureProperties(
+          pdfObject.getStatus().getSettings(), pdfObject, (PdfBoxVisualObject) visualObject,
+          positioningInstruction, signatureProfileSettings);
+
+      properties.buildSignature();
+      PDDocument visualDoc;
+      synchronized (PDDocument.class) {
+        visualDoc = PDDocument.load(properties.getVisibleSignature());
+      }
+      // PDPageable pageable = new PDPageable(visualDoc);
+
+      final PDPage firstPage = visualDoc.getDocumentCatalog().getPages().get(0);
+
+      final float stdRes = 72;
+      final float targetRes = resolution;
+      final float factor = targetRes / stdRes;
+
+      final int targetPageNumber = 0;// TODO: is this always the case
+      PDFRenderer pdfRenderer = new PDFRenderer(visualDoc);
+      final BufferedImage outputImage = pdfRenderer.renderImageWithDPI(targetPageNumber, targetRes,
+          ImageType.ARGB);
+
+      visualDoc.close();
+      pdfRenderer = null;
+      
+      final BufferedImage cutOut = new BufferedImage((int) (position.getWidth() * factor),
+          (int) (position.getHeight() * factor), BufferedImage.TYPE_4BYTE_ABGR);
+
+      final Graphics2D graphics = (Graphics2D) cutOut.getGraphics();
+
+      graphics.drawImage(outputImage, 0, 0, cutOut.getWidth(), cutOut.getHeight(), (int) (1 * factor),
+          (int) (outputImage.getHeight() - (position.getHeight() + 1) * factor),
+          (int) ((1 + position.getWidth()) * factor), (int) (outputImage.getHeight()
+              - (position.getHeight() + 1) * factor + position.getHeight() * factor),
+          null);
+      return cutOut;
+    } catch (final PdfAsException e) {
+      logger.warn("PDF-AS  Exception", e);
+      throw ErrorExtractor.searchPdfAsError(e, status);
+    } catch (final Throwable e) {
+      logger.warn("Unexpected Throwable  Exception", e);
+      throw ErrorExtractor.searchPdfAsError(e, status);
+    }
+  }
+
+  private String getPDFAVersion(PDDocument doc) {
+    try {
+      final PDDocumentCatalog cat = doc.getDocumentCatalog();
+      final PDMetadata metadata = cat.getMetadata();
+
+      if (metadata != null) {
+        final DomXmpParser xmpParser = new DomXmpParser();
+        final XMPMetadata xmpMetadata = xmpParser.parse(metadata.exportXMPMetadata());
+        if (xmpMetadata != null) {
+          final PDFAIdentificationSchema pdfaIdentificationSchema = xmpMetadata.getPDFIdentificationSchema();
+          if (pdfaIdentificationSchema != null) {
+            final Integer pdfaversion = pdfaIdentificationSchema.getPart();
+            final String conformance = pdfaIdentificationSchema.getConformance();
+            logger.info("Detected PDF/A Version: {} - {}", pdfaversion, conformance);
+
+            if (pdfaversion != null) {
+              return String.valueOf(pdfaversion);
             }
-        } catch (Throwable e) {
-            logger.warn("Failed to determine PDF/A Version!", e);
+          }
         }
-        return null;
+      }
+    } catch (final Throwable e) {
+      logger.warn("Failed to determine PDF/A Version!", e);
     }
-
-	// Find an existing signature.
-	private PDSignature findExistingSignature(PDDocument doc, String sigFieldName) {
-		PDSignature signature = null;
-		PDSignatureField signatureField;
-		PDAcroForm acroForm = doc.getDocumentCatalog().getAcroForm();
-		if (acroForm != null) {
-			signatureField = (PDSignatureField) acroForm.getField(sigFieldName);
-			if (signatureField != null) {
-				// retrieve signature dictionary
-				signature = signatureField.getSignature();
-				if (signature == null) {
-					signature = new PDSignature();
-					signatureField.getCOSObject().setItem(COSName.V, signature);
-				}
-				else {
-					throw new IllegalStateException("The signature field " + sigFieldName + " is already signed.");
-				}
-			}
-		}
-		return signature;
-	}
-
-	private List<String> existingSignatureLocations(PDDocument doc) {
-		List<String> existingLocations = new ArrayList<>();
-		try {
-			List <PDSignature> pdSignatureList =  doc.getSignatureDictionaries();
-			if(pdSignatureList.size() != 0) {
-				for(PDSignature sig : pdSignatureList) {
-					existingLocations.add(sig.getLocation());
-				}
-			}
-		} catch (IOException e) {
-			e.printStackTrace();
-		}
-		return existingLocations;
-	}
-
-	//find first placeholder_id
-	public SignaturePlaceholderData checkAvailablePlaceholders(List<SignaturePlaceholderData> placeholders, List<String> existingPlaceholders) {
-		SignaturePlaceholderData result = null;
-
-		if(placeholders!=null) {
-		for(int i = 0; i < placeholders.size(); ++i) {
-			//take smallest id
-			if(!existingPlaceholders.contains(placeholders.get(i).getPlaceholderName())) {
-				SignaturePlaceholderData spd = placeholders.get(i);
-				if (spd.getId() != null) {
-					if(result == null) {
-						result = spd;
-					} else {
-						try{
-							int currentID = Integer.parseInt(result.getId());
-							int testID = Integer.parseInt(spd.getId());
-							if(testID < currentID) {
-								result = spd;
-							}
-						}catch(Exception e){
-							//fallback to string compare
-							String currentID = result.getId();
-							String testID = spd.getId();
-							if(testID.compareToIgnoreCase(currentID) < 0) {
-								result = spd;
-							}
-						}
-					}
-				}
-			}
-		}
-	}
-		return result;
-	}
-
-
-	//find first placeholder_id
-	public List<SignaturePlaceholderData>  listAvailablePlaceholders(List<SignaturePlaceholderData> placeholders, List<String> existingPlaceholders) {
-		List<SignaturePlaceholderData> result = new ArrayList<>();
-
-		if(placeholders!=null) {
-			for(int i = 0; i < placeholders.size(); ++i) {
-				//take smallest id
-				if(!existingPlaceholders.contains(placeholders.get(i).getPlaceholderName())) {
-					result.add(placeholders.get(i));
-				}
-			}
-		}
-		return result;
-	}
-	
-	static Map<Integer, COSObjectable> getNumberTreeAsMap(PDNumberTreeNode tree)
-            throws IOException
-    {
-        Map<Integer, COSObjectable> numbers = tree.getNumbers();
-        if (numbers == null)
-        {
-            numbers = new LinkedHashMap<>();
+    return null;
+  }
+
+  // Find an existing signature.
+  private PDSignature findExistingSignature(PDDocument doc, String sigFieldName) {
+    PDSignature signature = null;
+    PDSignatureField signatureField;
+    final PDAcroForm acroForm = doc.getDocumentCatalog().getAcroForm();
+    if (acroForm != null) {
+      signatureField = (PDSignatureField) acroForm.getField(sigFieldName);
+      if (signatureField != null) {
+        // retrieve signature dictionary
+        signature = signatureField.getSignature();
+        if (signature == null) {
+          signature = new PDSignature();
+          signatureField.getCOSObject().setItem(COSName.V, signature);
+        } else {
+          throw new IllegalStateException("The signature field " + sigFieldName + " is already signed.");
         }
-        else
-        {
-            // must copy because the map is read only
-            numbers = new LinkedHashMap<>(numbers);
+      }
+    }
+    return signature;
+  }
+
+  private List<String> existingSignatureLocations(PDDocument doc) {
+    final List<String> existingLocations = new ArrayList<>();
+    try {
+      final List<PDSignature> pdSignatureList = doc.getSignatureDictionaries();
+      if (pdSignatureList.size() != 0) {
+        for (final PDSignature sig : pdSignatureList) {
+          existingLocations.add(sig.getLocation());
         }
-        List<PDNumberTreeNode> kids = tree.getKids();
-        if (kids != null)
-        {
-            for (PDNumberTreeNode kid : kids)
-            {
-                numbers.putAll(getNumberTreeAsMap(kid));
+      }
+    } catch (final IOException e) {
+      e.printStackTrace();
+    }
+    return existingLocations;
+  }
+
+  // find first placeholder_id
+  public SignaturePlaceholderData checkAvailablePlaceholders(List<SignaturePlaceholderData> placeholders,
+      List<String> existingPlaceholders) {
+    SignaturePlaceholderData result = null;
+
+    if (placeholders != null) {
+      for (int i = 0; i < placeholders.size(); ++i) {
+        // take smallest id
+        if (!existingPlaceholders.contains(placeholders.get(i).getPlaceholderName())) {
+          final SignaturePlaceholderData spd = placeholders.get(i);
+          if (spd.getId() != null) {
+            if (result == null) {
+              result = spd;
+            } else {
+              try {
+                final int currentID = Integer.parseInt(result.getId());
+                final int testID = Integer.parseInt(spd.getId());
+                if (testID < currentID) {
+                  result = spd;
+                }
+              } catch (final Exception e) {
+                // fallback to string compare
+                final String currentID = result.getId();
+                final String testID = spd.getId();
+                if (testID.compareToIgnoreCase(currentID) < 0) {
+                  result = spd;
+                }
+              }
             }
+          }
         }
-        return numbers;
+      }
     }
-	
+    return result;
+  }
+
+  // find first placeholder_id
+  public List<SignaturePlaceholderData> listAvailablePlaceholders(List<SignaturePlaceholderData> placeholders,
+      List<String> existingPlaceholders) {
+    final List<SignaturePlaceholderData> result = new ArrayList<>();
+
+    if (placeholders != null) {
+      for (int i = 0; i < placeholders.size(); ++i) {
+        // take smallest id
+        if (!existingPlaceholders.contains(placeholders.get(i).getPlaceholderName())) {
+          result.add(placeholders.get(i));
+        }
+      }
+    } 
+    return result;
+  }
+
+  static Map<Integer, COSObjectable> getNumberTreeAsMap(PDNumberTreeNode tree)
+      throws IOException {
+    Map<Integer, COSObjectable> numbers = tree.getNumbers();
+    if (numbers == null) {
+      numbers = new LinkedHashMap<>();
+    } else {
+      // must copy because the map is read only
+      numbers = new LinkedHashMap<>(numbers);
+    }
+    final List<PDNumberTreeNode> kids = tree.getKids();
+    if (kids != null) {
+      for (final PDNumberTreeNode kid : kids) {
+        numbers.putAll(getNumberTreeAsMap(kid));
+      }
+    }
+    return numbers;
+  }
+
 }
\ No newline at end of file