Java tutorial
/** * Licensed to Jasig under one or more contributor license * agreements. See the NOTICE file distributed with this work * for additional information regarding copyright ownership. * Jasig 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: * * 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.jasig.portlet.courses.dao.xml; import java.io.IOException; import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.ConcurrentMap; import javax.xml.bind.JAXBContext; import javax.xml.bind.JAXBElement; import javax.xml.bind.JAXBException; import javax.xml.bind.MarshalException; import javax.xml.bind.Marshaller; import javax.xml.bind.PropertyException; import javax.xml.bind.UnmarshalException; import javax.xml.bind.Unmarshaller; import javax.xml.bind.annotation.XmlRootElement; import javax.xml.bind.annotation.XmlType; import javax.xml.transform.Result; import javax.xml.transform.Source; import org.jasig.portlet.courses.model.wrapper.CourseSummaryWrapper; import org.jasig.portlet.courses.model.wrapper.ObjectFactoryWrapper; import org.springframework.core.annotation.AnnotationUtils; import org.springframework.http.HttpHeaders; import org.springframework.http.MediaType; import org.springframework.http.converter.HttpMessageConversionException; import org.springframework.http.converter.HttpMessageNotReadableException; import org.springframework.http.converter.HttpMessageNotWritableException; import org.springframework.http.converter.xml.AbstractJaxb2HttpMessageConverter; import org.springframework.util.Assert; import org.springframework.util.ClassUtils; public class Jaxb2CourseSummaryHttpMessageConverter extends AbstractJaxb2HttpMessageConverter<Object> { private final ConcurrentMap<Class, JAXBContext> jaxbContexts = new ConcurrentHashMap<Class, JAXBContext>(); protected boolean isSupported(MediaType mediaType) { if (mediaType == null) { return true; } for (MediaType supportedMediaType : getSupportedMediaTypes()) { if (supportedMediaType.includes(mediaType)) { return true; } } return false; } @Override public boolean canRead(Class<?> clazz, MediaType mediaType) { return (clazz.isAnnotationPresent(XmlRootElement.class) || clazz.isAnnotationPresent(XmlType.class) || clazz.getPackage().equals(CourseSummaryWrapper.class.getPackage())) && isSupported(mediaType); } @Override public boolean canWrite(Class<?> clazz, MediaType mediaType) { return AnnotationUtils.findAnnotation(clazz, XmlRootElement.class) != null && isSupported(mediaType); } /** * Creates a new {@link Marshaller} for the given class. * * @param clazz the class to create the marshaller for * @return the {@code Marshaller} * @throws HttpMessageConversionException in case of JAXB errors */ protected final Marshaller createWrapperMarshaller(Class clazz) { try { JAXBContext jaxbContext = getJaxbContext(clazz); return jaxbContext.createMarshaller(); } catch (JAXBException ex) { throw new HttpMessageConversionException( "Could not create Marshaller for class [" + clazz + "]: " + ex.getMessage(), ex); } } /** * Creates a new {@link Unmarshaller} for the given class. * * @param clazz the class to create the unmarshaller for * @return the {@code Unmarshaller} * @throws HttpMessageConversionException in case of JAXB errors */ protected final Unmarshaller createWrapperUnmarshaller(Class clazz) throws JAXBException { try { JAXBContext jaxbContext = getJaxbContext(clazz); Unmarshaller unmarshaller = jaxbContext.createUnmarshaller(); unmarshaller.setProperty("com.sun.xml.bind.ObjectFactory", new ObjectFactoryWrapper()); return unmarshaller; } catch (JAXBException ex) { throw new HttpMessageConversionException( "Could not create Unmarshaller for class [" + clazz + "]: " + ex.getMessage(), ex); } } /** * Returns a {@link JAXBContext} for the given class. * * @param clazz the class to return the context for * @return the {@code JAXBContext} * @throws HttpMessageConversionException in case of JAXB errors */ protected final JAXBContext getWrapperJaxbContext(Class clazz) { Assert.notNull(clazz, "'clazz' must not be null"); JAXBContext jaxbContext = jaxbContexts.get(clazz); if (jaxbContext == null) { try { jaxbContext = JAXBContext.newInstance(clazz); jaxbContexts.putIfAbsent(clazz, jaxbContext); } catch (JAXBException ex) { throw new HttpMessageConversionException( "Could not instantiate JAXBContext for class [" + clazz + "]: " + ex.getMessage(), ex); } } return jaxbContext; } @Override protected Object readFromSource(Class<? extends Object> clazz, HttpHeaders headers, Source source) throws IOException { try { Unmarshaller unmarshaller = createWrapperUnmarshaller(clazz); if (clazz.isAnnotationPresent(XmlRootElement.class)) { return unmarshaller.unmarshal(source); } else { JAXBElement<? extends Object> jaxbElement = unmarshaller.unmarshal(source, clazz); return jaxbElement.getValue(); } } catch (UnmarshalException ex) { throw new HttpMessageNotReadableException("Could not unmarshal to [" + clazz + "]: " + ex.getMessage(), ex); } catch (JAXBException ex) { throw new HttpMessageConversionException("Could not instantiate JAXBContext: " + ex.getMessage(), ex); } } @Override protected void writeToResult(Object o, HttpHeaders headers, Result result) throws IOException { try { Class clazz = ClassUtils.getUserClass(o); Marshaller marshaller = createWrapperMarshaller(clazz); setCharset(headers.getContentType(), marshaller); marshaller.marshal(o, result); } catch (MarshalException ex) { throw new HttpMessageNotWritableException("Could not marshal [" + o + "]: " + ex.getMessage(), ex); } catch (JAXBException ex) { throw new HttpMessageConversionException("Could not instantiate JAXBContext: " + ex.getMessage(), ex); } } @Override protected boolean supports(Class<?> arg0) { // should not be called, since we override canRead/Write throw new UnsupportedOperationException(); } private void setCharset(MediaType contentType, Marshaller marshaller) throws PropertyException { if (contentType != null && contentType.getCharSet() != null) { marshaller.setProperty(Marshaller.JAXB_ENCODING, contentType.getCharSet().name()); } } }