Java tutorial
/* Milyn - Copyright (C) 2006 - 2010 This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License (version 2.1) as published by the Free Software Foundation. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details: http://www.gnu.org/licenses/lgpl.txt */ package org.dhatim.delivery.dom.serialize; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.dhatim.cdr.ResourceConfigurationNotFoundException; import org.dhatim.cdr.SmooksResourceConfiguration; import org.dhatim.cdr.ParameterAccessor; import org.dhatim.container.ExecutionContext; import org.dhatim.event.ExecutionEventListener; import org.dhatim.delivery.ContentHandlerConfigMap; import org.dhatim.delivery.ContentHandlerConfigMapTable; import org.dhatim.delivery.Filter; import org.dhatim.event.types.ResourceTargetingEvent; import org.dhatim.event.types.ElementPresentEvent; import org.dhatim.event.types.DOMFilterLifecycleEvent; import org.dhatim.delivery.dom.DOMContentDeliveryConfig; import org.dhatim.xml.DocType; import org.dhatim.xml.DomUtils; import org.dhatim.SmooksException; import org.w3c.dom.*; import java.io.IOException; import java.io.Writer; import java.util.List; /** * Node serializer. * <p/> * This class uses the {@link org.dhatim.delivery.ContentDeliveryConfig} and the * {@link org.dhatim.delivery.dom.serialize.SerializationUnit} instances defined there on * to perform the serialization. * @author tfennelly */ public class Serializer { /** * Logger. */ private static Log logger = LogFactory.getLog(Serializer.class); /** * Node to be serialized. */ private Node node; /** * Target device context. */ private ExecutionContext executionContext; /** * Target content delivery config. */ private DOMContentDeliveryConfig deliveryConfig; /** * Target content delivery context SerializationUnit definitions. */ private ContentHandlerConfigMapTable<SerializationUnit> serializationUnits; /** * Turn default serialization on/off. Default is "true". */ private boolean defaultSerializationOn; /** * Default serialization unit. */ private DefaultSerializationUnit defaultSerializationUnit; /** * Global SerializationUnits. */ private List globalSUs; /** * Event Listener. */ private ExecutionEventListener eventListener; private boolean terminateOnVisitorException; /** * Public constructor. * @param node Node to be serialized. * @param executionContext Target device context. */ public Serializer(Node node, ExecutionContext executionContext) { if (node == null) { throw new IllegalArgumentException("null 'node' arg passed in method call."); } else if (executionContext == null) { throw new IllegalArgumentException("null 'executionContext' arg passed in method call."); } this.node = node; this.executionContext = executionContext; eventListener = executionContext.getEventListener(); // Get the delivery context for the device. deliveryConfig = (DOMContentDeliveryConfig) executionContext.getDeliveryConfig(); // Initialise the serializationUnits member serializationUnits = deliveryConfig.getSerailizationVisitors(); globalSUs = serializationUnits.getMappings(new String[] { "*", "**" }); // Set the default SerializationUnit defaultSerializationOn = ParameterAccessor.getBoolParameter(Filter.DEFAULT_SERIALIZATION_ON, true, executionContext.getDeliveryConfig()); if (defaultSerializationOn) { defaultSerializationUnit = new DefaultSerializationUnit(); boolean rewriteEntities = ParameterAccessor.getBoolParameter(Filter.ENTITIES_REWRITE, true, executionContext.getDeliveryConfig()); defaultSerializationUnit.setRewriteEntities(rewriteEntities); } terminateOnVisitorException = ParameterAccessor.getBoolParameter(Filter.TERMINATE_ON_VISITOR_EXCEPTION, true, executionContext.getDeliveryConfig()); } /** * Serialise the document to the supplied output writer instance. * <p/> * Adds the DOCTYPE decl if one defined in the Content Delivery Configuration. * <p/> * If the node is a Document (or DocumentFragment) node the whole node is serialised. * Otherwise, only the node child elements are serialised i.e. the node itself is skipped. * @param writer Output writer. * @throws ResourceConfigurationNotFoundException DOM Serialiser exception. * @throws IOException Unable to write to output writer. */ public void serailize(Writer writer) throws ResourceConfigurationNotFoundException, IOException { List docTypeUDs; if (writer == null) { throw new IllegalArgumentException("null 'writer' arg passed in method call."); } // Register the DOM phase events... if (eventListener != null) { eventListener.onEvent( new DOMFilterLifecycleEvent(DOMFilterLifecycleEvent.DOMEventType.SERIALIZATION_STARTED)); } if (node instanceof Document) { Document doc = (Document) node; Element rootElement = doc.getDocumentElement(); DocType.DocumentTypeData docTypeData = DocType.getDocType(executionContext); if (docTypeData != null) { DocType.serializeDoctype(docTypeData, writer); if (docTypeData.getXmlns() != null) { rootElement.setAttribute("xmlns", docTypeData.getXmlns()); } else { rootElement.removeAttribute("xmlns"); } } recursiveDOMWrite(rootElement, writer, true); } else { // Write the DOM, the child elements of the node NodeList deliveryNodes = node.getChildNodes(); int nodeCount = deliveryNodes.getLength(); boolean isRoot = (node == node.getOwnerDocument().getDocumentElement()); for (int i = 0; i < nodeCount; i++) { Node childNode = deliveryNodes.item(i); if (childNode.getNodeType() == Node.ELEMENT_NODE) { recursiveDOMWrite((Element) childNode, writer, isRoot); } } } } /** * Serialize the DocumentType. * <p/> * Only called if a DOCTYPE was suppied in the original source and * no doctype overrides were configured (in .cdrl) for the requesting * device. * @param publicId Docytype public ID. * @param systemId Docytype system ID. * @param rootElement The root element name. * @param writer The target writer. * @throws IOException Exception writing to the output writer. */ private void serializeDoctype(String publicId, String systemId, String rootElement, Writer writer) throws IOException { writer.write("<!DOCTYPE "); writer.write(rootElement); writer.write(' '); if (publicId != null) { writer.write("PUBLIC \""); writer.write(publicId); writer.write("\" "); } if (systemId != null) { writer.write('"'); writer.write(systemId); writer.write('"'); } writer.write('>'); writer.write('\n'); } /** * Recursively write the DOM tree to the supplied writer. * @param element Element to write. * @param writer Writer to use. * @param isRoot Is the supplied element the document root element. * @throws IOException Exception writing to Writer. */ private void recursiveDOMWrite(Element element, Writer writer, boolean isRoot) throws IOException { SerializationUnit elementSU; NodeList children = element.getChildNodes(); elementSU = getSerializationUnit(element, isRoot); try { if (elementSU != null) { elementSU.writeElementStart(element, writer, executionContext); } if (children != null && children.getLength() > 0) { int childCount = children.getLength(); for (int i = 0; i < childCount; i++) { Node childNode = children.item(i); if (elementSU != null) { switch (childNode.getNodeType()) { case Node.CDATA_SECTION_NODE: { elementSU.writeElementCDATA((CDATASection) childNode, writer, executionContext); break; } case Node.COMMENT_NODE: { elementSU.writeElementComment((Comment) childNode, writer, executionContext); break; } case Node.ELEMENT_NODE: { if (elementSU.writeChildElements()) { recursiveDOMWrite((Element) childNode, writer, false); } break; } case Node.ENTITY_REFERENCE_NODE: { elementSU.writeElementEntityRef((EntityReference) childNode, writer, executionContext); break; } case Node.TEXT_NODE: { elementSU.writeElementText((Text) childNode, writer, executionContext); break; } default: { elementSU.writeElementNode(childNode, writer, executionContext); break; } } } else if (childNode.getNodeType() == Node.ELEMENT_NODE) { recursiveDOMWrite((Element) childNode, writer, false); } } } if (elementSU != null) { elementSU.writeElementEnd(element, writer, executionContext); } } catch (Throwable thrown) { String error = "Failed to apply serialization unit [" + elementSU.getClass().getName() + "] to [" + executionContext.getDocumentSource() + ":" + DomUtils.getXPath(element) + "]."; if (terminateOnVisitorException) { if (thrown instanceof SmooksException) { throw (SmooksException) thrown; } else { throw new SmooksException(error, thrown); } } else { logger.debug(error, thrown); } } } /** * Get the first matching serialisation unit for the supplied element. * @param element Element to be serialized. * @param isRoot Is the supplied element the document root element. * @return SerializationUnit. */ private SerializationUnit getSerializationUnit(Element element, boolean isRoot) { String elementName = DomUtils.getName(element); List<ContentHandlerConfigMap<SerializationUnit>> elementSUs; // Register the "presence" of the element... if (eventListener != null) { eventListener.onEvent(new ElementPresentEvent(element)); } if (isRoot) { // The document as a whole (root node) can also be targeted through the "#document" selector. elementSUs = serializationUnits.getMappings( new String[] { SmooksResourceConfiguration.DOCUMENT_FRAGMENT_SELECTOR, elementName }); } else { elementSUs = serializationUnits.getMappings(elementName); } if (elementSUs == null || elementSUs.isEmpty()) { elementSUs = globalSUs; } if (elementSUs != null) { int numSUs = elementSUs.size(); for (int i = 0; i < numSUs; i++) { ContentHandlerConfigMap configMap = elementSUs.get(i); SmooksResourceConfiguration config = configMap.getResourceConfig(); // Make sure the serialization unit is targeted at this element. if (!config.isTargetedAtElement(element, executionContext)) { continue; } // Register the targeting event... if (eventListener != null) { eventListener.onEvent(new ResourceTargetingEvent(element, config)); } if (logger.isDebugEnabled()) { logger.debug("Applying serialisation resource [" + config + "] to element [" + DomUtils.getXPath(element) + "]."); } // This is the one, return it... return (SerializationUnit) configMap.getContentHandler(); } } return defaultSerializationUnit; } private static DefaultSerializationUnit defaultSerializer = new DefaultSerializationUnit(); static { defaultSerializer.setCloseEmptyElements(true); } /** * Recursively write the DOM tree to the supplied writer. * @param element Element to write. * @param writer Writer to use. * @throws IOException Exception writing to Writer. */ public static void recursiveDOMWrite(Element element, Writer writer) throws IOException { NodeList children = element.getChildNodes(); try { defaultSerializer.writeElementStart(element, writer); if (children != null && children.getLength() > 0) { int childCount = children.getLength(); for (int i = 0; i < childCount; i++) { Node childNode = children.item(i); switch (childNode.getNodeType()) { case Node.CDATA_SECTION_NODE: { defaultSerializer.writeElementCDATA((CDATASection) childNode, writer, null); break; } case Node.COMMENT_NODE: { defaultSerializer.writeElementComment((Comment) childNode, writer, null); break; } case Node.ELEMENT_NODE: { recursiveDOMWrite((Element) childNode, writer); break; } case Node.ENTITY_REFERENCE_NODE: { defaultSerializer.writeElementEntityRef((EntityReference) childNode, writer, null); break; } case Node.TEXT_NODE: { defaultSerializer.writeElementText((Text) childNode, writer, null); break; } default: { defaultSerializer.writeElementNode(childNode, writer, null); break; } } } } defaultSerializer.writeElementEnd(element, writer); } catch (Throwable thrown) { if (thrown instanceof SmooksException) { throw (SmooksException) thrown; } else { throw new SmooksException("Serailization Error.", thrown); } } } }