Java tutorial
/* * $Id$ * -------------------------------------------------------------------------------------- * Copyright (c) MuleSoft, Inc. All rights reserved. http://www.mulesoft.com * * The software in this package is published under the terms of the CPAL v1.0 * license, a copy of which has been included with this distribution in the * LICENSE.txt file. */ package org.mule.module.xml.util; import org.mule.RequestContext; import org.mule.api.MuleContext; import org.mule.api.transport.OutputHandler; import org.mule.module.xml.stax.DelegateXMLStreamReader; import org.mule.module.xml.stax.StaxSource; import org.mule.module.xml.transformer.DelayedResult; import org.mule.module.xml.transformer.XmlToDomDocument; import org.mule.transformer.types.DataTypeFactory; import org.mule.util.IOUtils; import java.io.ByteArrayInputStream; import java.io.File; import java.io.FileReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.Reader; import java.io.StringReader; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import javax.xml.namespace.NamespaceContext; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.stream.XMLStreamConstants; import javax.xml.stream.XMLStreamException; import javax.xml.stream.XMLStreamReader; import javax.xml.stream.XMLStreamWriter; import javax.xml.transform.Source; import javax.xml.transform.Transformer; import javax.xml.transform.TransformerConfigurationException; import javax.xml.transform.TransformerFactory; import javax.xml.transform.TransformerFactoryConfigurationError; import javax.xml.transform.dom.DOMResult; import javax.xml.transform.dom.DOMSource; import javax.xml.transform.sax.SAXSource; import javax.xml.transform.stream.StreamSource; import javax.xml.xpath.XPath; import javax.xml.xpath.XPathConstants; import javax.xml.xpath.XPathExpressionException; import javax.xml.xpath.XPathFactory; import org.apache.commons.io.output.ByteArrayOutputStream; import org.apache.commons.lang.StringUtils; import org.dom4j.DocumentException; import org.dom4j.io.DOMReader; import org.dom4j.io.DOMWriter; import org.dom4j.io.DocumentSource; import org.w3c.dom.Document; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import org.xml.sax.InputSource; /** * General utility methods for working with XML. */ public class XMLUtils extends org.mule.util.XMLUtils { public static final String TRANSFORMER_FACTORY_JDK5 = "com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl"; // xml parser feature names for optional XSD validation public static final String APACHE_XML_FEATURES_VALIDATION_SCHEMA = "http://apache.org/xml/features/validation/schema"; public static final String APACHE_XML_FEATURES_VALIDATION_SCHEMA_FULL_CHECKING = "http://apache.org/xml/features/validation/schema-full-checking"; // JAXP property for specifying external XSD location public static final String JAXP_PROPERTIES_SCHEMA_SOURCE = "http://java.sun.com/xml/jaxp/properties/schemaSource"; // JAXP properties for specifying external XSD language (as required by newer // JAXP implementation) public static final String JAXP_PROPERTIES_SCHEMA_LANGUAGE = "http://java.sun.com/xml/jaxp/properties/schemaLanguage"; public static final String JAXP_PROPERTIES_SCHEMA_LANGUAGE_VALUE = "http://www.w3.org/2001/XMLSchema"; /** * Converts a DOM to an XML string. * @param dom the dome object to convert * @return A string representation of the document */ public static String toXml(Document dom) { return new DOMReader().read(dom).asXML(); } /** * @return a new XSLT transformer * @throws TransformerConfigurationException if no TransformerFactory can be located in the * runtime environment. */ public static Transformer getTransformer() throws TransformerConfigurationException { TransformerFactory tf; try { tf = TransformerFactory.newInstance(); } catch (TransformerFactoryConfigurationError e) { System.setProperty("javax.xml.transform.TransformerFactory", TRANSFORMER_FACTORY_JDK5); tf = TransformerFactory.newInstance(); } if (tf != null) { return tf.newTransformer(); } else { throw new TransformerConfigurationException("Unable to instantiate a TransformerFactory"); } } public static org.dom4j.Document toDocument(Object obj, MuleContext muleContext) throws Exception { return toDocument(obj, null, muleContext); } /** * Converts an object of unknown type to an org.dom4j.Document if possible. * @return null if object cannot be converted * @throws DocumentException if an error occurs while parsing */ public static org.dom4j.Document toDocument(Object obj, String externalSchemaLocation, MuleContext muleContext) throws Exception { org.dom4j.io.SAXReader reader = new org.dom4j.io.SAXReader(); if (externalSchemaLocation != null) { reader.setValidation(true); reader.setFeature(APACHE_XML_FEATURES_VALIDATION_SCHEMA, true); reader.setFeature(APACHE_XML_FEATURES_VALIDATION_SCHEMA_FULL_CHECKING, true); InputStream xsdAsStream = IOUtils.getResourceAsStream(externalSchemaLocation, XMLUtils.class); if (xsdAsStream == null) { throw new IllegalArgumentException("Couldn't find schema at " + externalSchemaLocation); } // Set schema language property (must be done before the schemaSource // is set) reader.setProperty(JAXP_PROPERTIES_SCHEMA_LANGUAGE, JAXP_PROPERTIES_SCHEMA_LANGUAGE_VALUE); // Need this one to map schemaLocation to a physical location reader.setProperty(JAXP_PROPERTIES_SCHEMA_SOURCE, xsdAsStream); } if (obj instanceof org.dom4j.Document) { return (org.dom4j.Document) obj; } else if (obj instanceof org.w3c.dom.Document) { org.dom4j.io.DOMReader domReader = new org.dom4j.io.DOMReader(); return domReader.read((org.w3c.dom.Document) obj); } else if (obj instanceof org.xml.sax.InputSource) { return reader.read((org.xml.sax.InputSource) obj); } else if (obj instanceof javax.xml.transform.Source || obj instanceof javax.xml.stream.XMLStreamReader) { // TODO Find a more direct way to do this XmlToDomDocument tr = new XmlToDomDocument(); tr.setMuleContext(muleContext); tr.setReturnDataType(DataTypeFactory.create(org.dom4j.Document.class)); return (org.dom4j.Document) tr.transform(obj); } else if (obj instanceof java.io.InputStream) { return reader.read((java.io.InputStream) obj); } else if (obj instanceof String) { return reader.read(new StringReader((String) obj)); } else if (obj instanceof byte[]) { // TODO Handle encoding/charset somehow return reader.read(new StringReader(new String((byte[]) obj))); } else if (obj instanceof File) { return reader.read((File) obj); } else { return null; } } /** * Converts a payload to a {@link org.w3c.dom.Document} representation. * <p> Reproduces the behavior from {@link org.mule.module.xml.util.XMLUtils#toDocument(Object, MuleContext)} * which works converting to {@link org.dom4j.Document}. * * @param payload the payload to convert. * @return a document from the payload or null if the payload is not a valid XML document. */ public static org.w3c.dom.Document toW3cDocument(Object payload) throws Exception { if (payload instanceof org.dom4j.Document) { DOMWriter writer = new DOMWriter(); org.w3c.dom.Document w3cDocument = writer.write((org.dom4j.Document) payload); return w3cDocument; } else if (payload instanceof org.w3c.dom.Document) { return (org.w3c.dom.Document) payload; } else if (payload instanceof org.xml.sax.InputSource) { return parseXML((InputSource) payload); } else if (payload instanceof javax.xml.transform.Source || payload instanceof javax.xml.stream.XMLStreamReader) { DOMResult result = new DOMResult(); Transformer idTransformer = getTransformer(); Source source = (payload instanceof Source) ? (Source) payload : toXmlSource(null, true, payload); idTransformer.transform(source, result); return (Document) result.getNode(); } else if (payload instanceof java.io.InputStream) { InputStreamReader input = new InputStreamReader((InputStream) payload); return parseXML(input); } else if (payload instanceof String) { Reader input = new StringReader((String) payload); return parseXML(input); } else if (payload instanceof byte[]) { // TODO Handle encoding/charset somehow Reader input = new StringReader(new String((byte[]) payload)); return parseXML(input); } else if (payload instanceof File) { Reader input = new FileReader((File) payload); return parseXML(input); } else { return null; } } private static org.w3c.dom.Document parseXML(Reader source) throws Exception { return parseXML(new InputSource(source)); } private static org.w3c.dom.Document parseXML(InputSource source) throws Exception { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); return factory.newDocumentBuilder().parse(source); } /** * Returns an XMLStreamReader for an object of unknown type if possible. * @return null if no XMLStreamReader can be created for the object type * @throws XMLStreamException */ public static javax.xml.stream.XMLStreamReader toXMLStreamReader(javax.xml.stream.XMLInputFactory factory, Object obj) throws XMLStreamException { if (obj instanceof javax.xml.stream.XMLStreamReader) { return (javax.xml.stream.XMLStreamReader) obj; } else if (obj instanceof org.mule.module.xml.stax.StaxSource) { return ((org.mule.module.xml.stax.StaxSource) obj).getXMLStreamReader(); } else if (obj instanceof javax.xml.transform.Source) { return factory.createXMLStreamReader((javax.xml.transform.Source) obj); } else if (obj instanceof org.xml.sax.InputSource) { return factory.createXMLStreamReader(((org.xml.sax.InputSource) obj).getByteStream()); } else if (obj instanceof org.w3c.dom.Document) { return factory.createXMLStreamReader(new javax.xml.transform.dom.DOMSource((org.w3c.dom.Document) obj)); } else if (obj instanceof org.dom4j.Document) { return factory.createXMLStreamReader(new org.dom4j.io.DocumentSource((org.dom4j.Document) obj)); } else if (obj instanceof java.io.InputStream) { final InputStream is = (java.io.InputStream) obj; XMLStreamReader xsr = factory.createXMLStreamReader(is); return new DelegateXMLStreamReader(xsr) { @Override public void close() throws XMLStreamException { super.close(); try { is.close(); } catch (IOException e) { throw new XMLStreamException(e); } } }; } else if (obj instanceof String) { return factory.createXMLStreamReader(new StringReader((String) obj)); } else if (obj instanceof byte[]) { // TODO Handle encoding/charset? return factory.createXMLStreamReader(new ByteArrayInputStream((byte[]) obj)); } else { return null; } } /** * Convert our object to a Source type efficiently. */ public static javax.xml.transform.Source toXmlSource(javax.xml.stream.XMLInputFactory xmlInputFactory, boolean useStaxSource, Object src) throws Exception { if (src instanceof javax.xml.transform.Source) { return (Source) src; } else if (src instanceof byte[]) { ByteArrayInputStream stream = new ByteArrayInputStream((byte[]) src); return toStreamSource(xmlInputFactory, useStaxSource, stream); } else if (src instanceof InputStream) { return toStreamSource(xmlInputFactory, useStaxSource, (InputStream) src); } else if (src instanceof String) { if (useStaxSource) { return new StaxSource(xmlInputFactory.createXMLStreamReader(new StringReader((String) src))); } else { return new StreamSource(new StringReader((String) src)); } } else if (src instanceof org.dom4j.Document) { return new DocumentSource((org.dom4j.Document) src); } else if (src instanceof org.xml.sax.InputSource) { return new SAXSource((InputSource) src); } // TODO MULE-3555 else if (src instanceof XMLStreamReader) { XMLStreamReader xsr = (XMLStreamReader) src; // StaxSource requires that we advance to a start element/document event if (!xsr.isStartElement() && xsr.getEventType() != XMLStreamConstants.START_DOCUMENT) { xsr.nextTag(); } return new StaxSource((XMLStreamReader) src); } else if (src instanceof org.w3c.dom.Document || src instanceof org.w3c.dom.Element) { return new DOMSource((org.w3c.dom.Node) src); } else if (src instanceof DelayedResult) { DelayedResult result = ((DelayedResult) src); DOMResult domResult = new DOMResult(); result.write(domResult); return new DOMSource(domResult.getNode()); } else if (src instanceof OutputHandler) { OutputHandler handler = ((OutputHandler) src); ByteArrayOutputStream output = new ByteArrayOutputStream(); handler.write(RequestContext.getEvent(), output); return toStreamSource(xmlInputFactory, useStaxSource, new ByteArrayInputStream(output.toByteArray())); } else { return null; } } public static javax.xml.transform.Source toStreamSource(javax.xml.stream.XMLInputFactory xmlInputFactory, boolean useStaxSource, InputStream stream) throws XMLStreamException { if (useStaxSource) { return new org.mule.module.xml.stax.StaxSource(xmlInputFactory.createXMLStreamReader(stream)); } else { return new javax.xml.transform.stream.StreamSource(stream); } } /** * Copies the reader to the writer. The start and end document methods must * be handled on the writer manually. TODO: if the namespace on the reader * has been declared previously to where we are in the stream, this probably * won't work. * * @param reader * @param writer * @throws XMLStreamException */ public static void copy(XMLStreamReader reader, XMLStreamWriter writer) throws XMLStreamException { copy(reader, writer, false); } public static void copy(XMLStreamReader reader, XMLStreamWriter writer, boolean fragment) throws XMLStreamException { // number of elements read in int read = 0; int event = reader.getEventType(); while (reader.hasNext()) { switch (event) { case XMLStreamConstants.START_ELEMENT: read++; writeStartElement(reader, writer); break; case XMLStreamConstants.END_ELEMENT: writer.writeEndElement(); read--; if (read <= 0 && !fragment) { return; } break; case XMLStreamConstants.CHARACTERS: writer.writeCharacters(reader.getText()); break; case XMLStreamConstants.START_DOCUMENT: case XMLStreamConstants.END_DOCUMENT: case XMLStreamConstants.ATTRIBUTE: case XMLStreamConstants.NAMESPACE: break; default: break; } event = reader.next(); } } private static void writeStartElement(XMLStreamReader reader, XMLStreamWriter writer) throws XMLStreamException { String local = reader.getLocalName(); String uri = reader.getNamespaceURI(); String prefix = reader.getPrefix(); if (prefix == null) { prefix = ""; } // System.out.println("STAXUTILS:writeStartElement : node name : " + local + " namespace URI" + uri); boolean writeElementNS = false; if (uri != null) { String boundPrefix = writer.getPrefix(uri); if (boundPrefix == null || !prefix.equals(boundPrefix)) { writeElementNS = true; } } // Write out the element name if (uri != null) { if (prefix.length() == 0 && StringUtils.isEmpty(uri)) { writer.writeStartElement(local); writer.setDefaultNamespace(uri); } else { writer.writeStartElement(prefix, local, uri); writer.setPrefix(prefix, uri); } } else { writer.writeStartElement(local); } // Write out the namespaces for (int i = 0; i < reader.getNamespaceCount(); i++) { String nsURI = reader.getNamespaceURI(i); String nsPrefix = reader.getNamespacePrefix(i); if (nsPrefix == null) { nsPrefix = ""; } if (nsPrefix.length() == 0) { writer.writeDefaultNamespace(nsURI); } else { writer.writeNamespace(nsPrefix, nsURI); } if (nsURI.equals(uri) && nsPrefix.equals(prefix)) { writeElementNS = false; } } // Check if the namespace still needs to be written. // We need this check because namespace writing works // different on Woodstox and the RI. if (writeElementNS) { if (prefix.length() == 0) { writer.writeDefaultNamespace(uri); } else { writer.writeNamespace(prefix, uri); } } // Write out attributes for (int i = 0; i < reader.getAttributeCount(); i++) { String ns = reader.getAttributeNamespace(i); String nsPrefix = reader.getAttributePrefix(i); if (ns == null || ns.length() == 0) { writer.writeAttribute(reader.getAttributeLocalName(i), reader.getAttributeValue(i)); } else if (nsPrefix == null || nsPrefix.length() == 0) { writer.writeAttribute(reader.getAttributeNamespace(i), reader.getAttributeLocalName(i), reader.getAttributeValue(i)); } else { writer.writeAttribute(reader.getAttributePrefix(i), reader.getAttributeNamespace(i), reader.getAttributeLocalName(i), reader.getAttributeValue(i)); } } } /** * Creates an XPath object with a custom NamespaceContext given the Node to operate on * @param node the Node or document to operate on. Note that namespace handling will not work if a Node fragment is passed in * @return a new XPath object */ private static XPath createXPath(Node node) { XPath xp = XPathFactory.newInstance().newXPath(); if (node instanceof Document) { xp.setNamespaceContext(new XPathNamespaceContext((Document) node)); } return xp; } /** * Select a single XML node using an Xpath * @param xpath the XPath expression to evaluate * @param node the node (or document) to exaluate on * @return the result of the evaluation. * @throws XPathExpressionException if the XPath expression is malformed and cannot be parsed */ public static Node selectOne(String xpath, Node node) throws XPathExpressionException { XPath xp = createXPath(node); return (Node) xp.evaluate(xpath, node, XPathConstants.NODE); } /** * Select a single XML String value using an Xpath * @param xpath the XPath expression to evaluate * @param node the node (or document) to evaluate on * @return the result of the evaluation. * @throws XPathExpressionException if the XPath expression is malformed and cannot be parsed */ public static String selectValue(String xpath, Node node) throws XPathExpressionException { XPath xp = createXPath(node); return (String) xp.evaluate(xpath, node, XPathConstants.STRING); } /** * Select a set of Node objects using the Xpath expression * @param xpath the XPath expression to evaluate * @param node the node (or document) to evaluate on * @return the result of the evaluation. * @throws XPathExpressionException if the XPath expression is malformed and cannot be parsed */ public static List<Node> select(String xpath, Node node) throws XPathExpressionException { XPath xp = createXPath(node); NodeList nl = (NodeList) xp.evaluate(xpath, node, XPathConstants.NODESET); List<Node> nodeList = new ArrayList<Node>(nl.getLength()); for (int i = 0; i < nl.getLength(); i++) { nodeList.add(nl.item(i)); } return nodeList; } /** * The default namespace context that will read namespaces from the current document if the * Node being processed is a Document */ private static class XPathNamespaceContext implements NamespaceContext { private Document document; public XPathNamespaceContext(Document document) { this.document = document; } public String getNamespaceURI(String prefix) { if (prefix == null || prefix.equals("")) { return document.getDocumentElement().getNamespaceURI(); } else { return document.lookupNamespaceURI(prefix); } } public String getPrefix(String namespaceURI) { return document.lookupPrefix(namespaceURI); } public Iterator<String> getPrefixes(String namespaceURI) { List<String> list = new ArrayList<String>(); list.add(getPrefix(namespaceURI)); return list.iterator(); } } }