Java tutorial
/******************************************************************************* * This file is part of OpenNMS(R). * * Copyright (C) 2011-2012 The OpenNMS Group, Inc. * OpenNMS(R) is Copyright (C) 1999-2012 The OpenNMS Group, Inc. * * OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc. * * OpenNMS(R) is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published * by the Free Software Foundation, either version 3 of the License, * or (at your option) any later version. * * OpenNMS(R) 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with OpenNMS(R). If not, see: * http://www.gnu.org/licenses/ * * For more information contact: * OpenNMS(R) Licensing <license@opennms.org> * http://www.opennms.org/ * http://www.opennms.com/ *******************************************************************************/ package com.netxforge.oss2.core.xml; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; import java.io.InputStream; import java.io.Reader; import java.io.StringReader; import java.io.StringWriter; import java.io.Writer; import java.net.URL; import java.util.Collections; import java.util.Map; import java.util.WeakHashMap; import javax.xml.bind.JAXBContext; import javax.xml.bind.JAXBElement; import javax.xml.bind.JAXBException; import javax.xml.bind.Marshaller; import javax.xml.bind.Unmarshaller; import javax.xml.bind.ValidationEvent; import javax.xml.bind.ValidationEventHandler; import javax.xml.bind.annotation.XmlSchema; import javax.xml.transform.sax.SAXSource; import javax.xml.transform.stream.StreamSource; import javax.xml.validation.Schema; import javax.xml.validation.SchemaFactory; import org.apache.commons.io.IOUtils; import org.springframework.core.io.Resource; import org.xml.sax.InputSource; import org.xml.sax.SAXException; import org.xml.sax.XMLFilter; import org.xml.sax.XMLReader; import org.xml.sax.helpers.XMLReaderFactory; import com.netxforge.oss2.core.utilsII.LogUtils; public abstract class JaxbUtils { private static final class LoggingValidationEventHandler implements ValidationEventHandler { private final Class<?> m_clazz; private LoggingValidationEventHandler(Class<?> clazz) { m_clazz = clazz; } @Override public boolean handleEvent(final ValidationEvent event) { LogUtils.tracef(m_clazz, event.getLinkedException(), "event = %s", event); return false; } } private static final MarshallingExceptionTranslator EXCEPTION_TRANSLATOR = new MarshallingExceptionTranslator(); private static ThreadLocal<Map<Class<?>, Marshaller>> m_marshallers = new ThreadLocal<Map<Class<?>, Marshaller>>(); private static ThreadLocal<Map<Class<?>, Unmarshaller>> m_unMarshallers = new ThreadLocal<Map<Class<?>, Unmarshaller>>(); private static final Map<Class<?>, JAXBContext> m_contexts = Collections .synchronizedMap(new WeakHashMap<Class<?>, JAXBContext>()); private static final Map<Class<?>, Schema> m_schemas = Collections .synchronizedMap(new WeakHashMap<Class<?>, Schema>()); private static final boolean VALIDATE_IF_POSSIBLE = true; private JaxbUtils() { } public static String marshal(final Object obj) { final StringWriter jaxbWriter = new StringWriter(); marshal(obj, jaxbWriter); return jaxbWriter.toString(); } public static void marshal(final Object obj, final Writer writer) { final Marshaller jaxbMarshaller = getMarshallerFor(obj, null); try { jaxbMarshaller.marshal(obj, writer); } catch (final JAXBException e) { throw EXCEPTION_TRANSLATOR.translate("marshalling " + obj.getClass().getSimpleName(), e); } } public static <T> T unmarshal(final Class<T> clazz, final File file) { return unmarshal(clazz, file, VALIDATE_IF_POSSIBLE); } public static <T> T unmarshal(final Class<T> clazz, final File file, final boolean validate) { FileReader reader = null; try { reader = new FileReader(file); return unmarshal(clazz, new InputSource(reader), null, validate); } catch (final FileNotFoundException e) { throw EXCEPTION_TRANSLATOR.translate("reading " + file, e); } finally { IOUtils.closeQuietly(reader); } } public static <T> T unmarshal(final Class<T> clazz, final Reader reader) { return unmarshal(clazz, reader, VALIDATE_IF_POSSIBLE); } public static <T> T unmarshal(final Class<T> clazz, final Reader reader, final boolean validate) { return unmarshal(clazz, new InputSource(reader), null, validate); } public static <T> T unmarshal(final Class<T> clazz, final String xml) { return unmarshal(clazz, xml, VALIDATE_IF_POSSIBLE); } public static <T> T unmarshal(final Class<T> clazz, final String xml, final boolean validate) { final StringReader sr = new StringReader(xml); final InputSource is = new InputSource(sr); try { return unmarshal(clazz, is, null, validate); } finally { IOUtils.closeQuietly(sr); } } public static <T> T unmarshal(final Class<T> clazz, final Resource resource) { return unmarshal(clazz, resource, VALIDATE_IF_POSSIBLE); } public static <T> T unmarshal(final Class<T> clazz, final Resource resource, final boolean validate) { try { return unmarshal(clazz, new InputSource(resource.getInputStream()), null, validate); } catch (final IOException e) { throw EXCEPTION_TRANSLATOR.translate("getting a configuration resource from spring", e); } } public static <T> T unmarshal(final Class<T> clazz, final InputSource inputSource) { return unmarshal(clazz, inputSource, VALIDATE_IF_POSSIBLE); } public static <T> T unmarshal(final Class<T> clazz, final InputSource inputSource, final boolean validate) { return unmarshal(clazz, inputSource, null, validate); } public static <T> T unmarshal(final Class<T> clazz, final InputSource inputSource, final JAXBContext jaxbContext) { return unmarshal(clazz, inputSource, jaxbContext, VALIDATE_IF_POSSIBLE); } public static <T> T unmarshal(final Class<T> clazz, final InputSource inputSource, final JAXBContext jaxbContext, final boolean validate) { final Unmarshaller um = getUnmarshallerFor(clazz, jaxbContext, validate); LogUtils.tracef(clazz, "unmarshalling class %s from input source %s with unmarshaller %s", clazz.getSimpleName(), inputSource, um); try { final XMLFilter filter = getXMLFilterForClass(clazz); final SAXSource source = new SAXSource(filter, inputSource); um.setEventHandler(new LoggingValidationEventHandler(clazz)); final JAXBElement<T> element = um.unmarshal(source, clazz); return element.getValue(); } catch (final SAXException e) { throw EXCEPTION_TRANSLATOR.translate("creating an XML reader object", e); } catch (final JAXBException e) { throw EXCEPTION_TRANSLATOR.translate("unmarshalling an object (" + clazz.getSimpleName() + ")", e); } } public static <T> XMLFilter getXMLFilterForClass(final Class<T> clazz) throws SAXException { final XMLFilter filter; final XmlSchema schema = clazz.getPackage().getAnnotation(XmlSchema.class); if (schema != null) { final String namespace = schema.namespace(); if (namespace != null && !"".equals(namespace)) { LogUtils.tracef(clazz, "found namespace %s for class %s", namespace, clazz); filter = new SimpleNamespaceFilter(namespace, true); } else { filter = new SimpleNamespaceFilter("", false); } } else { filter = new SimpleNamespaceFilter("", false); } final XMLReader xmlReader = XMLReaderFactory.createXMLReader(); filter.setParent(xmlReader); return filter; } public static Marshaller getMarshallerFor(final Object obj, final JAXBContext jaxbContext) { final Class<?> clazz = (Class<?>) (obj instanceof Class<?> ? obj : obj.getClass()); Map<Class<?>, Marshaller> marshallers = m_marshallers.get(); if (jaxbContext == null) { if (marshallers == null) { marshallers = new WeakHashMap<Class<?>, Marshaller>(); m_marshallers.set(marshallers); } if (marshallers.containsKey(clazz)) { LogUtils.tracef(clazz, "found unmarshaller for %s", clazz); return marshallers.get(clazz); } } LogUtils.tracef(clazz, "creating unmarshaller for %s", clazz); try { final JAXBContext context; if (jaxbContext == null) { context = getContextFor(clazz); } else { context = jaxbContext; } final Marshaller marshaller = context.createMarshaller(); marshaller.setProperty(Marshaller.JAXB_ENCODING, "UTF-8"); marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE); final Schema schema = getValidatorFor(clazz); marshaller.setSchema(schema); if (jaxbContext == null) marshallers.put(clazz, marshaller); return marshaller; } catch (JAXBException e) { throw EXCEPTION_TRANSLATOR.translate("creating XML marshaller", e); } } /** * Get a JAXB unmarshaller for the given object. If no JAXBContext is provided, * JAXBUtils will create and cache a context for the given object. * @param obj The object type to be unmarshaled. * @param jaxbContext An optional JAXB context to create the unmarshaller from. * @param validate TODO * @return an Unmarshaller */ public static Unmarshaller getUnmarshallerFor(final Object obj, final JAXBContext jaxbContext, boolean validate) { final Class<?> clazz = (Class<?>) (obj instanceof Class<?> ? obj : obj.getClass()); Unmarshaller unmarshaller = null; Map<Class<?>, Unmarshaller> unmarshallers = m_unMarshallers.get(); if (jaxbContext == null) { if (unmarshallers == null) { unmarshallers = new WeakHashMap<Class<?>, Unmarshaller>(); m_unMarshallers.set(unmarshallers); } if (unmarshallers.containsKey(clazz)) { LogUtils.tracef(clazz, "found unmarshaller for %s", clazz); unmarshaller = unmarshallers.get(clazz); } } if (unmarshaller == null) { try { final JAXBContext context; if (jaxbContext == null) { context = getContextFor(clazz); } else { context = jaxbContext; } unmarshaller = context.createUnmarshaller(); } catch (final JAXBException e) { throw EXCEPTION_TRANSLATOR.translate("creating XML marshaller", e); } } LogUtils.tracef(clazz, "created unmarshaller for %s", clazz); if (validate) { final Schema schema = getValidatorFor(clazz); if (schema == null) { LogUtils.tracef(clazz, "Validation is enabled, but no XSD found for class %s", clazz.getSimpleName()); } unmarshaller.setSchema(schema); } if (jaxbContext == null) unmarshallers.put(clazz, unmarshaller); return unmarshaller; } private static JAXBContext getContextFor(final Class<?> clazz) throws JAXBException { final JAXBContext context; if (m_contexts.containsKey(clazz)) { context = m_contexts.get(clazz); } else { context = JAXBContext.newInstance(clazz); m_contexts.put(clazz, context); } return context; } private static Schema getValidatorFor(final Class<?> origClazz) { final Class<?> clazz = (Class<?>) (origClazz instanceof Class<?> ? origClazz : origClazz.getClass()); LogUtils.tracef(clazz, "finding XSD for class %s", clazz); if (m_schemas.containsKey(clazz)) { return m_schemas.get(clazz); } final ValidateUsing schemaFileAnnotation = clazz.getAnnotation(ValidateUsing.class); if (schemaFileAnnotation == null || schemaFileAnnotation.value() == null) { return null; } final String schemaFileName = schemaFileAnnotation.value(); InputStream schemaInputStream = null; try { final SchemaFactory factory = SchemaFactory.newInstance("http://www.w3.org/2001/XMLSchema"); if (schemaInputStream == null) { final File schemaFile = new File( System.getProperty("opennms.home") + "/share/xsds/" + schemaFileName); if (schemaFile.exists()) { LogUtils.tracef(clazz, "using file %s", schemaFile); schemaInputStream = new FileInputStream(schemaFile); } ; } if (schemaInputStream == null) { final File schemaFile = new File("target/xsds/" + schemaFileName); if (schemaFile.exists()) { LogUtils.tracef(clazz, "using file %s", schemaFile); schemaInputStream = new FileInputStream(schemaFile); } ; } if (schemaInputStream == null) { final URL schemaResource = Thread.currentThread().getContextClassLoader() .getResource("xsds/" + schemaFileName); if (schemaResource == null) { LogUtils.debugf(clazz, "Unable to load resource xsds/%s from the classpath.", schemaFileName); } else { LogUtils.tracef(clazz, "using resource %s from classpath", schemaResource); schemaInputStream = schemaResource.openStream(); } } if (schemaInputStream == null) { LogUtils.tracef(clazz, "Did not find a suitable XSD. Skipping."); return null; } final Schema schema = factory.newSchema(new StreamSource(schemaInputStream)); m_schemas.put(clazz, schema); return schema; } catch (final Throwable t) { LogUtils.warnf(clazz, t, "an error occurred while attempting to load %s for validation", schemaFileName); return null; } finally { IOUtils.closeQuietly(schemaInputStream); } } }