Java tutorial
/** * Licensed to Apereo under one or more contributor license * agreements. See the NOTICE file distributed with this work * for additional information regarding copyright ownership. * Apereo licenses this file to you under the Apache License, * Version 2.0 (the "License"); you may not use this file * except in compliance with the License. You may obtain a * copy of the License at the following location: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ package org.apereo.portal.rendering.xslt; import java.util.List; import java.util.Map; import java.util.Properties; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.xml.stream.XMLEventReader; import javax.xml.stream.XMLStreamException; import javax.xml.stream.XMLStreamReader; import javax.xml.stream.events.XMLEvent; import javax.xml.transform.ErrorListener; import javax.xml.transform.OutputKeys; import javax.xml.transform.Source; import javax.xml.transform.Transformer; import javax.xml.transform.TransformerException; import javax.xml.transform.sax.SAXResult; import javax.xml.transform.stax.StAXSource; import org.apache.commons.logging.LogFactory; import org.apereo.portal.rendering.PipelineEventReader; import org.apereo.portal.rendering.PipelineEventReaderImpl; import org.apereo.portal.rendering.StAXPipelineComponentWrapper; import org.apereo.portal.utils.cache.CacheKey; import org.apereo.portal.xml.ResourceLoaderURIResolver; import org.apereo.portal.xml.StaxUtils; import org.apereo.portal.xml.stream.XMLEventBufferReader; import org.apereo.portal.xml.stream.XMLEventBufferWriter; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.BeanNameAware; import org.springframework.context.ResourceLoaderAware; import org.springframework.core.io.ResourceLoader; import org.springframework.util.xml.FixedXMLEventStreamReader; import org.springframework.util.xml.SimpleTransformErrorListener; import org.xml.sax.ContentHandler; import org.xml.sax.helpers.LocatorImpl; /** * @author Eric Dalquist * @version $Revision$ */ public class XSLTComponent extends StAXPipelineComponentWrapper implements BeanNameAware, ResourceLoaderAware { protected final Logger logger = LoggerFactory.getLogger(this.getClass()); private final ErrorListener errorListener; private ResourceLoaderURIResolver uriResolver; private TransformerSource transformerSource; private TransformerConfigurationSource xsltParameterSource; private String beanName; public XSLTComponent() { this.errorListener = new SimpleTransformErrorListener(LogFactory.getLog(this.getClass())); } public void setXsltParameterSource(TransformerConfigurationSource xsltParameterSource) { this.xsltParameterSource = xsltParameterSource; } public void setTransformerSource(TransformerSource transformerSource) { this.transformerSource = transformerSource; } @Override public void setBeanName(String name) { this.beanName = name; } @Override public void setResourceLoader(ResourceLoader resourceLoader) { this.uriResolver = new ResourceLoaderURIResolver(resourceLoader); } /* (non-Javadoc) * @see org.apereo.portal.rendering.StAXPipelineComponent#getXmlStreamReader(java.lang.Object, java.lang.Object) */ @Override public PipelineEventReader<XMLEventReader, XMLEvent> getEventReader(HttpServletRequest request, HttpServletResponse response) { final PipelineEventReader<XMLEventReader, XMLEvent> pipelineEventReader = this.wrappedComponent .getEventReader(request, response); final Transformer transformer = this.transformerSource.getTransformer(request, response); //Setup a URIResolver based on the current resource loader transformer.setURIResolver(this.uriResolver); //Configure the Transformer via injected class if (this.xsltParameterSource != null) { final Map<String, Object> transformerParameters = this.xsltParameterSource.getParameters(request, response); if (transformerParameters != null) { this.logger.debug("{} - Setting Transformer Parameters: ", this.beanName, transformerParameters); for (final Map.Entry<String, Object> transformerParametersEntry : transformerParameters .entrySet()) { final String name = transformerParametersEntry.getKey(); final Object value = transformerParametersEntry.getValue(); if (value != null) { transformer.setParameter(name, value); } } } final Properties outputProperties = this.xsltParameterSource.getOutputProperties(request, response); if (outputProperties != null) { this.logger.debug("{} - Setting Transformer Output Properties: ", this.beanName, outputProperties); transformer.setOutputProperties(outputProperties); } } //The event reader from the previous component in the pipeline final XMLEventReader eventReader = pipelineEventReader.getEventReader(); //Wrap the event reader in a stream reader to avoid a JDK bug final XMLStreamReader streamReader; try { streamReader = new FixedXMLEventStreamReader(eventReader); } catch (XMLStreamException e) { throw new RuntimeException("Failed to create XMLStreamReader from XMLEventReader", e); } final Source xmlReaderSource = new StAXSource(streamReader); //Setup logging for the transform transformer.setErrorListener(this.errorListener); //Transform to a SAX ContentHandler to avoid JDK bug: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6775588 final XMLEventBufferWriter eventWriterBuffer = new XMLEventBufferWriter(); final ContentHandler contentHandler = StaxUtils.createLexicalContentHandler(eventWriterBuffer); contentHandler.setDocumentLocator(new LocatorImpl()); final SAXResult outputTarget = new SAXResult(contentHandler); try { this.logger.debug("{} - Begining XML Transformation", this.beanName); transformer.transform(xmlReaderSource, outputTarget); this.logger.debug("{} - XML Transformation complete", this.beanName); } catch (TransformerException e) { throw new RuntimeException("Failed to transform document", e); } final String mediaType = transformer.getOutputProperty(OutputKeys.MEDIA_TYPE); final List<XMLEvent> eventBuffer = eventWriterBuffer.getEventBuffer(); final XMLEventReader outputEventReader = new XMLEventBufferReader(eventBuffer.listIterator()); final Map<String, String> outputProperties = pipelineEventReader.getOutputProperties(); final PipelineEventReaderImpl<XMLEventReader, XMLEvent> pipelineEventReaderImpl = new PipelineEventReaderImpl<XMLEventReader, XMLEvent>( outputEventReader, outputProperties); pipelineEventReaderImpl.setOutputProperty(OutputKeys.MEDIA_TYPE, mediaType); return pipelineEventReaderImpl; } @Override public CacheKey getCacheKey(HttpServletRequest request, HttpServletResponse response) { final CacheKey parentCacheKey = this.wrappedComponent.getCacheKey(request, response); final CacheKey transformerKey; if (transformerSource != null) { transformerKey = this.transformerSource.getCacheKey(request, response); } else { transformerKey = null; } final CacheKey transformerConfigurationKey; if (this.xsltParameterSource != null) { transformerConfigurationKey = this.xsltParameterSource.getCacheKey(request, response); } else { transformerConfigurationKey = null; } return CacheKey.build(this.beanName, parentCacheKey, transformerKey, transformerConfigurationKey); } }