diff options
Diffstat (limited to 'spss.server/src/at/gv/egovernment/moa/spss/server/iaik/xml/XSLTTransformationImpl.java')
-rw-r--r-- | spss.server/src/at/gv/egovernment/moa/spss/server/iaik/xml/XSLTTransformationImpl.java | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/spss.server/src/at/gv/egovernment/moa/spss/server/iaik/xml/XSLTTransformationImpl.java b/spss.server/src/at/gv/egovernment/moa/spss/server/iaik/xml/XSLTTransformationImpl.java new file mode 100644 index 000000000..d38da650b --- /dev/null +++ b/spss.server/src/at/gv/egovernment/moa/spss/server/iaik/xml/XSLTTransformationImpl.java @@ -0,0 +1,168 @@ +package at.gv.egovernment.moa.spss.server.iaik.xml; + +import java.io.IOException; +import java.io.InputStream; +import java.util.Collections; + +import org.w3c.dom.Element; +import org.w3c.dom.NodeList; + +import iaik.ixsil.algorithms.CanonicalizationAlgorithm; +import iaik.ixsil.algorithms.CanonicalizationAlgorithmImplExclusiveCanonicalXML; +import iaik.ixsil.exceptions.AlgorithmException; +import iaik.server.modules.xml.XSLTTransformation; + +import at.gv.egovernment.moa.util.NodeListAdapter; +import at.gv.egovernment.moa.util.StreamUtils; +import at.gv.egovernment.moa.util.XPathException; +import at.gv.egovernment.moa.util.XPathUtils; + + +/** + * A <code>Transformation</code> containing an XSLT transformation. + * + * @author Patrick Peck + * @version $Id$ + */ +public class XSLTTransformationImpl + extends TransformationImpl + implements XSLTTransformation { + + /** The XSLT stylesheet. */ + private Element styleSheetElement; + /** The hash code of the canonicalized stylesheet. If calculated, this value + * should be != 0. */ + private int hashCode; + + /** + * Create a new <code>XSLTTransformationImpl</code> object. + * + * @param styleSheetElement The XSLT stylesheet element. + */ + public XSLTTransformationImpl(Element styleSheetElement) { + setAlgorithmURI(XSLTTransformation.XSLT); + setStyleSheetElement(styleSheetElement); + } + + /** + * Set the XSLT stylesheet element. + * + * @param styleSheetElement The XSLT stylesheet element to set. + */ + protected void setStyleSheetElement(Element styleSheetElement) { + this.styleSheetElement = styleSheetElement; + this.hashCode = 0; + } + + /** + * @see iaik.server.modules.xml.XSLTTransformation#getStylesheetElement() + */ + public Element getStylesheetElement() { + return styleSheetElement; + } + + /** + * Compare this <code>XSLTTransformation</code> to another. + * + * @param other The object to compare this + * <code>XSLTTransformation</code> to. + * @return <code>true</code>, if <code>other</code> is an + * <code>XSLTTransformation</code> and if the canonicalized representations of + * the stylesheets contained in <code>this</code> and <code>other</code> + * match. Otherwise, <code>false</code> is returned. + * @see java.lang.Object#equals(Object) + */ + public boolean equals(Object other) { + if (other instanceof XSLTTransformation) { + XSLTTransformation xslt = (XSLTTransformation) other; + + return compareElements( + getStylesheetElement(), + xslt.getStylesheetElement()); + } + return false; + } + + /** + * @see java.lang.Object#hashCode() + */ + public int hashCode() { + if (hashCode == 0) { + hashCode = calculateHashCode(getStylesheetElement()); + } + return hashCode; + } + + /** + * Calculate the hash code for a DOM element by canonicalizing it. + * + * @param element The DOM element for which the hash code is to be calculated. + * @return int The hash code, or <code>0</code>, if it could not be + * calculated. + */ + private static int calculateHashCode(Element element) { + try { + InputStream is = canonicalize(element); + byte[] buf = new byte[256]; + int hashCode = 1; + int length; + int i; + + while ((length = is.read(buf)) > 0) { + for (i = 0; i < length; i++) { + hashCode += buf[i] * 31 + i; + } + } + is.close(); + return hashCode; + } catch (AlgorithmException e) { + return 0; + } catch (IOException e) { + return 0; + } + } + + /** + * Compare two DOM elements by canonicalizing their contents and comparing the + * resulting byte stream. + * + * @param elem1 The 1st element to compare. + * @param elem2 The 2nd element to compare. + * @return boolean <code>true</code>, if the elements are considered equal + * after canonicalization. Otherwise <code>false</code> is returned. + */ + private static boolean compareElements(Element elem1, Element elem2) { + try { + InputStream is1 = canonicalize(elem1); + InputStream is2 = canonicalize(elem2); + return StreamUtils.compareStreams(is1, is2); + } catch (AlgorithmException e) { + return false; + } catch (IOException e) { + return false; + } + } + + /** + * Canonicalize a DOM element. + * + * @param element The element to canonicalize. + * @return InputStream A stream with the canonicalized data. + * @throws AlgorithmException An error occurred canonicalizing the element. + */ + private static InputStream canonicalize(Element element) + throws AlgorithmException { + CanonicalizationAlgorithm c14n = + new CanonicalizationAlgorithmImplExclusiveCanonicalXML(); + NodeList nodeList; + + try { + nodeList = XPathUtils.selectNodeList(element, XPathUtils.ALL_NODES_XPATH); + } catch (XPathException e) { + nodeList = new NodeListAdapter(Collections.EMPTY_LIST); + } + c14n.setInput(nodeList); + return c14n.canonicalize(); + } + +} |