package at.gv.egovernment.moa.util; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.util.HashMap; import java.util.HashSet; import java.util.Iterator; import java.util.Map; import java.util.Set; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import javax.xml.transform.OutputKeys; import javax.xml.transform.Transformer; import javax.xml.transform.TransformerException; import javax.xml.transform.TransformerFactory; import javax.xml.transform.dom.DOMSource; import javax.xml.transform.stream.StreamResult; import org.w3c.dom.Attr; import org.w3c.dom.Document; import org.w3c.dom.DocumentFragment; import org.w3c.dom.Element; import org.w3c.dom.NamedNodeMap; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import org.apache.xerces.parsers.DOMParser; import org.apache.xerces.parsers.SAXParser; import org.apache.xerces.parsers.XMLGrammarPreparser; import org.apache.xerces.util.SymbolTable; import org.apache.xerces.util.XMLGrammarPoolImpl; import org.apache.xerces.xni.grammars.XMLGrammarDescription; import org.apache.xerces.xni.grammars.XMLGrammarPool; import org.apache.xerces.xni.parser.XMLInputSource; import org.xml.sax.EntityResolver; import org.xml.sax.ErrorHandler; import org.xml.sax.InputSource; import org.xml.sax.SAXException; /** * Various utility functions for handling XML DOM trees. * * The parsing methods in this class make use of some features internal to the * Xerces DOM parser, mainly for performance reasons. As soon as JAXP * (currently at version 1.2) is better at schema handling, it should be used as * the parser interface. * * @author Patrick Peck * @version $Id$ */ public class DOMUtils { /** Feature URI for namespace aware parsing. */ private static final String NAMESPACES_FEATURE = "http://xml.org/sax/features/namespaces"; /** Feature URI for validating parsing. */ private static final String VALIDATION_FEATURE = "http://xml.org/sax/features/validation"; /** Feature URI for schema validating parsing. */ private static final String SCHEMA_VALIDATION_FEATURE = "http://apache.org/xml/features/validation/schema"; /** Feature URI for normalization of element/attribute values. */ private static final String NORMALIZED_VALUE_FEATURE = "http://apache.org/xml/features/validation/schema/normalized-value"; /** Feature URI for parsing ignorable whitespace. */ private static final String INCLUDE_IGNORABLE_WHITESPACE_FEATURE = "http://apache.org/xml/features/dom/include-ignorable-whitespace"; /** Feature URI for creating EntityReference nodes in the DOM tree. */ private static final String CREATE_ENTITY_REF_NODES_FEATURE = "http://apache.org/xml/features/dom/create-entity-ref-nodes"; /** Property URI for providing external schema locations. */ private static final String EXTERNAL_SCHEMA_LOCATION_PROPERTY = "http://apache.org/xml/properties/schema/external-schemaLocation"; /** Property URI for providing the external schema location for elements * without a namespace. */ private static final String EXTERNAL_NO_NAMESPACE_SCHEMA_LOCATION_PROPERTY = "http://apache.org/xml/properties/schema/external-noNamespaceSchemaLocation"; /** Property URI for the Xerces grammar pool. */ private static final String GRAMMAR_POOL = org.apache.xerces.impl.Constants.XERCES_PROPERTY_PREFIX + org.apache.xerces.impl.Constants.XMLGRAMMAR_POOL_PROPERTY; /** A prime number for initializing the symbol table. */ private static final int BIG_PRIME = 2039; /** Symbol table for the grammar pool. */ private static SymbolTable symbolTable = new SymbolTable(BIG_PRIME); /** Xerces schema grammar pool. */ private static XMLGrammarPool grammarPool = new XMLGrammarPoolImpl(); static { grammarPool.lockPool(); } /** * Preparse a schema and add it to the schema pool. * * @param inputStream An InputStream providing the contents of * the schema. * @param systemId The systemId to use for the schema. * @throws IOException An error occurred reading the schema. */ public static void addSchemaToPool(InputStream inputStream, String systemId) throws IOException { XMLGrammarPreparser preparser; // unlock the pool so that we can add another grammar grammarPool.unlockPool(); // prepare the preparser preparser = new XMLGrammarPreparser(symbolTable); preparser.registerPreparser(XMLGrammarDescription.XML_SCHEMA, null); preparser.setProperty(GRAMMAR_POOL, grammarPool); preparser.setFeature(NAMESPACES_FEATURE, true); preparser.setFeature(VALIDATION_FEATURE, true); // add the grammar to the pool preparser.preparseGrammar( XMLGrammarDescription.XML_SCHEMA, new XMLInputSource(null, systemId, null, inputStream, null)); // lock the pool again so that schemas are not added automatically grammarPool.lockPool(); } /** * Parse an XML document from an InputStream. * * @param inputStream The InputStream containing the XML * document. * @param validating If true, parse validating. * @param externalSchemaLocations A String containing namespace * URI to schema location pairs, the same way it is accepted by the xsi: * schemaLocation attribute. * @param externalNoNamespaceSchemaLocation The schema location of the * schema for elements without a namespace, the same way it is accepted by the * xsi:noNamespaceSchemaLocation attribute. * @param entityResolver An EntityResolver to resolve external * entities (schemas and DTDs). If null, it will not be set. * @param errorHandler An ErrorHandler to decide what to do * with parsing errors. If null, it will not be set. * @return The parsed XML document as a DOM tree. * @throws SAXException An error occurred parsing the document. * @throws IOException An error occurred reading the document. * @throws ParserConfigurationException An error occurred configuring the XML * parser. */ public static Document parseDocument( InputStream inputStream, boolean validating, String externalSchemaLocations, String externalNoNamespaceSchemaLocation, EntityResolver entityResolver, ErrorHandler errorHandler) throws SAXException, IOException, ParserConfigurationException { DOMParser parser; // create the DOM parser if (symbolTable != null) { parser = new DOMParser(symbolTable, grammarPool); } else { parser = new DOMParser(); } // set parser features and properties parser.setFeature(NAMESPACES_FEATURE, true); parser.setFeature(VALIDATION_FEATURE, validating); parser.setFeature(SCHEMA_VALIDATION_FEATURE, validating); parser.setFeature(NORMALIZED_VALUE_FEATURE, false); parser.setFeature(INCLUDE_IGNORABLE_WHITESPACE_FEATURE, true); parser.setFeature(CREATE_ENTITY_REF_NODES_FEATURE, false); if (validating) { if (externalSchemaLocations != null) { parser.setProperty( EXTERNAL_SCHEMA_LOCATION_PROPERTY, externalSchemaLocations); } if (externalNoNamespaceSchemaLocation != null) { parser.setProperty( EXTERNAL_NO_NAMESPACE_SCHEMA_LOCATION_PROPERTY, externalNoNamespaceSchemaLocation); } } // set entity resolver and error handler if (entityResolver != null) { parser.setEntityResolver(entityResolver); } if (errorHandler != null) { parser.setErrorHandler(errorHandler); } // parse the document and return it parser.parse(new InputSource(inputStream)); return parser.getDocument(); } /** * Parse an XML document from an InputStream. * * It uses a MOAEntityResolver as the EntityResolver * and a MOAErrorHandler as the ErrorHandler. * * @param inputStream The InputStream containing the XML * document. * @param validating If true, parse validating. * @param externalSchemaLocations A String containing namespace * URI to schema location pairs, the same way it is accepted by the xsi: * schemaLocation attribute. * @param externalNoNamespaceSchemaLocation The schema location of the * schema for elements without a namespace, the same way it is accepted by the * xsi:noNamespaceSchemaLocation attribute. * @return The parsed XML document as a DOM tree. * @throws SAXException An error occurred parsing the document. * @throws IOException An error occurred reading the document. * @throws ParserConfigurationException An error occurred configuring the XML * parser. */ public static Document parseDocument( InputStream inputStream, boolean validating, String externalSchemaLocations, String externalNoNamespaceSchemaLocation) throws SAXException, IOException, ParserConfigurationException { return parseDocument( inputStream, validating, externalSchemaLocations, externalNoNamespaceSchemaLocation, new MOAEntityResolver(), new MOAErrorHandler()); } /** * Parse an XML document from a String. * * It uses a MOAEntityResolver as the EntityResolver * and a MOAErrorHandler as the ErrorHandler. * * @param xmlString The String containing the XML document. * @param encoding The encoding of the XML document. * @param validating If true, parse validating. * @param externalSchemaLocations A String containing namespace * URI to schema location pairs, the same way it is accepted by the xsi: * schemaLocation attribute. * @param externalNoNamespaceSchemaLocation The schema location of the * schema for elements without a namespace, the same way it is accepted by the * xsi:noNamespaceSchemaLocation attribute. * @return The parsed XML document as a DOM tree. * @throws SAXException An error occurred parsing the document. * @throws IOException An error occurred reading the document. * @throws ParserConfigurationException An error occurred configuring the XML * parser. */ public static Document parseDocument( String xmlString, String encoding, boolean validating, String externalSchemaLocations, String externalNoNamespaceSchemaLocation) throws SAXException, IOException, ParserConfigurationException { InputStream in = new ByteArrayInputStream(xmlString.getBytes(encoding)); return parseDocument( in, validating, externalSchemaLocations, externalNoNamespaceSchemaLocation); } /** * Parse an UTF-8 encoded XML document from a String. * * @param xmlString The String containing the XML document. * @param validating If true, parse validating. * @param externalSchemaLocations A String containing namespace * URI to schema location pairs, the same way it is accepted by the xsi: * schemaLocation attribute. * @param externalNoNamespaceSchemaLocation The schema location of the * schema for elements without a namespace, the same way it is accepted by the * xsi:noNamespaceSchemaLocation attribute. * @return The parsed XML document as a DOM tree. * @throws SAXException An error occurred parsing the document. * @throws IOException An error occurred reading the document. * @throws ParserConfigurationException An error occurred configuring the XML * parser. */ public static Document parseDocument( String xmlString, boolean validating, String externalSchemaLocations, String externalNoNamespaceSchemaLocation) throws SAXException, IOException, ParserConfigurationException { return parseDocument( xmlString, "UTF-8", validating, externalSchemaLocations, externalNoNamespaceSchemaLocation); } /** * A convenience method to parse an XML document validating. * * @param inputStream The InputStream containing the XML * document. * @return The root element of the parsed XML document. * @throws SAXException An error occurred parsing the document. * @throws IOException An error occurred reading the document. * @throws ParserConfigurationException An error occurred configuring the XML * parser. */ public static Element parseXmlValidating(InputStream inputStream) throws ParserConfigurationException, SAXException, IOException { return DOMUtils .parseDocument(inputStream, true, Constants.ALL_SCHEMA_LOCATIONS, null) .getDocumentElement(); } /** * Schema validate a given DOM element. * * @param element The element to validate. * @param externalSchemaLocations A String containing namespace * URI to schema location pairs, the same way it is accepted by the xsi: * schemaLocation attribute. * @param externalNoNamespaceSchemaLocation The schema location of the * schema for elements without a namespace, the same way it is accepted by the * xsi:noNamespaceSchemaLocation attribute. * @return true, if the element validates against * the schemas declared in it. * @throws SAXException An error occurred parsing the document. * @throws IOException An error occurred reading the document from its * serialized representation. * @throws ParserConfigurationException An error occurred configuring the XML * @throws TransformerException An error occurred serializing the element. */ public static boolean validateElement( Element element, String externalSchemaLocations, String externalNoNamespaceSchemaLocation) throws ParserConfigurationException, IOException, SAXException, TransformerException { byte[] docBytes; SAXParser parser; // create the SAX parser if (symbolTable != null) { parser = new SAXParser(symbolTable, grammarPool); } else { parser = new SAXParser(); } // serialize the document docBytes = serializeNode(element, "UTF-8"); // set up parser features and attributes parser.setFeature(NAMESPACES_FEATURE, true); parser.setFeature(VALIDATION_FEATURE, true); parser.setFeature(SCHEMA_VALIDATION_FEATURE, true); if (externalSchemaLocations != null) { parser.setProperty( EXTERNAL_SCHEMA_LOCATION_PROPERTY, externalSchemaLocations); } if (externalNoNamespaceSchemaLocation != null) { parser.setProperty( EXTERNAL_NO_NAMESPACE_SCHEMA_LOCATION_PROPERTY, "externalNoNamespaceSchemaLocation"); } // set up entity resolver and error handler parser.setEntityResolver(new MOAEntityResolver()); parser.setErrorHandler(new MOAErrorHandler()); // parse validating parser.parse(new InputSource(new ByteArrayInputStream(docBytes))); return true; } /** * Serialize the given DOM node. * * The node will be serialized using the UTF-8 encoding. * * @param node The node to serialize. * @return String The String representation of the given DOM * node. * @throws TransformerException An error occurred transforming the * node to a String. * @throws IOException An IO error occurred writing the node to a byte array. */ public static String serializeNode(Node node) throws TransformerException, IOException { return new String(serializeNode(node, "UTF-8"), "UTF-8"); } /** * Serialize the given DOM node to a byte array. * * @param node The node to serialize. * @param xmlEncoding The XML encoding to use. * @return The serialized node, as a byte array. Using a compatible encoding * this can easily be converted into a String. * @throws TransformerException An error occurred transforming the node to a * byte array. * @throws IOException An IO error occurred writing the node to a byte array. */ public static byte[] serializeNode(Node node, String xmlEncoding) throws TransformerException, IOException { TransformerFactory transformerFactory = TransformerFactory.newInstance(); Transformer transformer = transformerFactory.newTransformer(); ByteArrayOutputStream bos = new ByteArrayOutputStream(16384); transformer.setOutputProperty(OutputKeys.METHOD, "xml"); transformer.setOutputProperty(OutputKeys.ENCODING, xmlEncoding); transformer.transform(new DOMSource(node), new StreamResult(bos)); bos.flush(); bos.close(); return bos.toByteArray(); } /** * Return the text that a node contains. * * This routine: * * * @param node A DOM node from which to extract text. * @return A String representing its contents. */ public static String getText(Node node) { if (!node.hasChildNodes()) { return ""; } StringBuffer result = new StringBuffer(); NodeList list = node.getChildNodes(); for (int i = 0; i < list.getLength(); i++) { Node subnode = list.item(i); if (subnode.getNodeType() == Node.TEXT_NODE) { result.append(subnode.getNodeValue()); } else if (subnode.getNodeType() == Node.CDATA_SECTION_NODE) { result.append(subnode.getNodeValue()); } else if (subnode.getNodeType() == Node.ENTITY_REFERENCE_NODE) { // Recurse into the subtree for text // (and ignore comments) result.append(getText(subnode)); } } return result.toString(); } /** * Build the namespace prefix to namespace URL mapping in effect for a given * node. * * @param node The context node for which build the map. * @return The namespace prefix to namespace URL mapping ( * a String value to String value mapping). */ public static Map getNamespaceDeclarations(Node node) { Map nsDecls = new HashMap(); int i; do { if (node.hasAttributes()) { NamedNodeMap attrs = node.getAttributes(); for (i = 0; i < attrs.getLength(); i++) { Attr attr = (Attr) attrs.item(i); // add prefix mapping if none exists if ("xmlns".equals(attr.getPrefix()) || "xmlns".equals(attr.getName())) { String nsPrefix = attr.getPrefix() != null ? attr.getLocalName() : ""; if (nsDecls.get(nsPrefix) == null) { nsDecls.put(nsPrefix, attr.getValue()); } } } } } while ((node = node.getParentNode()) != null); return nsDecls; } /** * Add all namespace declarations declared in the parent(s) of a given * element and used in the subtree of the given element to the given element. * * @param context The element to which to add the namespaces. */ public static void localizeNamespaceDeclarations(Element context) { Node parent = context.getParentNode(); if (parent != null) { Map namespaces = getNamespaceDeclarations(context.getParentNode()); Set nsUris = collectNamespaceURIs(context); Iterator iter; for (iter = namespaces.entrySet().iterator(); iter.hasNext();) { Map.Entry e = (Map.Entry) iter.next(); if (nsUris.contains(e.getValue())) { String prefix = (String) e.getKey(); String nsUri = (String) e.getValue(); String nsAttrName = "".equals(prefix) ? "xmlns" : "xmlns:" + prefix; context.setAttributeNS(Constants.XMLNS_NS_URI, nsAttrName, nsUri); } } } } /** * Collect all the namespace URIs used in the subtree of a given element. * * @param context The element that should be searched for namespace URIs. * @return All namespace URIs used in the subtree of context, * including the ones used in context itself. */ public static Set collectNamespaceURIs(Element context) { Set result = new HashSet(); collectNamespaceURIsImpl(context, result); return result; } /** * A recursive method to do the work of collectNamespaceURIs. * * @param context The context element to evaluate. * @param result The result, passed as a parameter to avoid unnecessary * instantiations of Set. */ private static void collectNamespaceURIsImpl(Element context, Set result) { NamedNodeMap attrs = context.getAttributes(); NodeList childNodes = context.getChildNodes(); String nsUri; int i; // add the namespace of the context element nsUri = context.getNamespaceURI(); if (nsUri != null && nsUri != Constants.XMLNS_NS_URI) { result.add(nsUri); } // add all namespace URIs from attributes for (i = 0; i < attrs.getLength(); i++) { nsUri = attrs.item(i).getNamespaceURI(); if (nsUri != null && nsUri != Constants.XMLNS_NS_URI) { result.add(nsUri); } } // add all namespaces from subelements for (i = 0; i < childNodes.getLength(); i++) { Node node = childNodes.item(i); if (node.getNodeType() == Node.ELEMENT_NODE) { collectNamespaceURIsImpl((Element) node, result); } } } /** * Check, that each attribute node in the given NodeList has its * parent in the NodeList as well. * * @param nodes The NodeList to check. * @return true, if each attribute node in nodes * has its parent in nodes as well. */ public static boolean checkAttributeParentsInNodeList(NodeList nodes) { Set nodeSet = new HashSet(); int i; // put the nodes into the nodeSet for (i = 0; i < nodes.getLength(); i++) { nodeSet.add(nodes.item(i)); } // check that each attribute node's parent is in the node list for (i = 0; i < nodes.getLength(); i++) { Node n = nodes.item(i); if (n.getNodeType() == Node.ATTRIBUTE_NODE) { Attr attr = (Attr) n; Element owner = attr.getOwnerElement(); if (owner == null) { if (!isNamespaceDeclaration(attr)) { return false; } } if (!nodeSet.contains(owner) && !isNamespaceDeclaration(attr)) { return false; } } } return true; } /** * Convert an unstructured NodeList into a * DocumentFragment. * * @param nodeList Contains the node list to be converted into a DOM * DocumentFragment. * @return the resulting DocumentFragment. The DocumentFragment will be * backed by a new DOM Document, i.e. all noded of the node list will be * cloned. * @throws ParserConfigurationException An error occurred creating the * DocumentFragment. * @precondition The nodes in the node list appear in document order. * @precondition For each Attr node in the node list, the owning Element is * in the node list as well. * @precondition Each Element or Attr node in the node list is namespace * aware. */ public static DocumentFragment nodeList2DocumentFragment(NodeList nodeList) throws ParserConfigurationException { DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder(); Document doc = builder.newDocument(); DocumentFragment result = doc.createDocumentFragment(); if (null == nodeList || nodeList.getLength() == 0) { return result; } int currPos = 0; currPos = nodeList2DocumentFragment(nodeList, currPos, result, null, null) + 1; while (currPos < nodeList.getLength()) { currPos = nodeList2DocumentFragment(nodeList, currPos, result, null, null) + 1; } return result; } /** * Helper method for the nodeList2DocumentFragment. * * @param nodeList The NodeList to convert. * @param currPos The current position in the nodeList. * @param result The resulting DocumentFragment. * @param currOrgElem The current original element. * @param currClonedElem The current cloned element. * @return The current position. */ private static int nodeList2DocumentFragment( NodeList nodeList, int currPos, DocumentFragment result, Element currOrgElem, Element currClonedElem) { while (currPos < nodeList.getLength()) { Node currentNode = nodeList.item(currPos); switch (currentNode.getNodeType()) { case Node.COMMENT_NODE : case Node.PROCESSING_INSTRUCTION_NODE : case Node.TEXT_NODE : { // Append current node either to resulting DocumentFragment or to // current cloned Element if (null == currClonedElem) { result.appendChild( result.getOwnerDocument().importNode(currentNode, false)); } else { // Stop processing if current Node is not a descendant of // current Element if (!isAncestor(currOrgElem, currentNode)) { return --currPos; } currClonedElem.appendChild( result.getOwnerDocument().importNode(currentNode, false)); } break; } case Node.ELEMENT_NODE : { Element nextCurrOrgElem = (Element) currentNode; Element nextCurrClonedElem = result.getOwnerDocument().createElementNS( nextCurrOrgElem.getNamespaceURI(), nextCurrOrgElem.getNodeName()); // Append current Node either to resulting DocumentFragment or to // current cloned Element if (null == currClonedElem) { result.appendChild(nextCurrClonedElem); currOrgElem = nextCurrOrgElem; currClonedElem = nextCurrClonedElem; } else { // Stop processing if current Node is not a descendant of // current Element if (!isAncestor(currOrgElem, currentNode)) { return --currPos; } currClonedElem.appendChild(nextCurrClonedElem); } // Process current Node (of type Element) recursively currPos = nodeList2DocumentFragment( nodeList, ++currPos, result, nextCurrOrgElem, nextCurrClonedElem); break; } case Node.ATTRIBUTE_NODE : { Attr currAttr = (Attr) currentNode; // GK 20030411: Hack to overcome problems with IAIK IXSIL if (currAttr.getOwnerElement() == null) break; if (currClonedElem == null) break; // currClonedElem must be the owner Element of currAttr if // preconditions are met currClonedElem.setAttributeNS( currAttr.getNamespaceURI(), currAttr.getNodeName(), currAttr.getValue()); break; } default : { // All other nodes will be ignored } } currPos++; } return currPos; } /** * Check, if the given attribute is a namespace declaration. * * @param attr The attribute to check. * @return true, if the attribute is a namespace declaration, * false otherwise. */ private static boolean isNamespaceDeclaration(Attr attr) { return Constants.XMLNS_NS_URI.equals(attr.getNamespaceURI()); } /** * Check, if a given DOM element is an ancestor of a given node. * * @param candAnc The DOM element to check for being the ancestor. * @param cand The node to check for being the child. * @return true, if candAnc is an (indirect) * ancestor of cand; false otherwise. */ public static boolean isAncestor(Element candAnc, Node cand) { Node currPar = cand.getParentNode(); while (currPar != null) { if (candAnc == currPar) return true; currPar = currPar.getParentNode(); } return false; } }