001 /*
002 * Copyright 2005-2007 The Kuali Foundation
003 *
004 * Licensed under the Educational Community License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.opensource.org/licenses/ecl2.php
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017 package org.kuali.rice.kns.service.impl;
018
019 import com.thoughtworks.xstream.XStream;
020 import com.thoughtworks.xstream.converters.MarshallingContext;
021 import com.thoughtworks.xstream.converters.reflection.ObjectAccessException;
022 import com.thoughtworks.xstream.converters.reflection.PureJavaReflectionProvider;
023 import com.thoughtworks.xstream.converters.reflection.ReflectionConverter;
024 import com.thoughtworks.xstream.converters.reflection.ReflectionProvider;
025 import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
026 import com.thoughtworks.xstream.mapper.Mapper;
027 import org.apache.commons.logging.Log;
028 import org.apache.commons.logging.LogFactory;
029 import org.apache.ojb.broker.core.proxy.ListProxyDefaultImpl;
030 import org.apache.ojb.broker.core.proxy.ProxyHelper;
031 import org.kuali.rice.kns.service.KNSServiceLocator;
032 import org.kuali.rice.kns.service.PersistenceService;
033 import org.kuali.rice.kns.service.XmlObjectSerializerService;
034
035 import javax.xml.transform.*;
036 import javax.xml.transform.dom.DOMSource;
037 import javax.xml.transform.stream.StreamResult;
038 import java.io.StringWriter;
039 import java.lang.reflect.Field;
040 import java.util.ArrayList;
041 import java.util.Iterator;
042
043
044 /**
045 * This class is the service implementation for the XmlObjectSerializer structure. This is the default implementation that gets
046 * delivered with Kuali. It utilizes the XStream open source libraries and framework.
047 *
048 *
049 */
050 public class XmlObjectSerializerServiceImpl implements XmlObjectSerializerService {
051 private static final Log LOG = LogFactory.getLog(XmlObjectSerializerServiceImpl.class);
052
053 private PersistenceService persistenceService;
054
055 private XStream xstream;
056
057 public XmlObjectSerializerServiceImpl() {
058 xstream = new XStream(new ProxyAwareJavaReflectionProvider());
059 xstream.registerConverter(new ProxyConverter(xstream.getMapper(), xstream.getReflectionProvider() ));
060 xstream.addDefaultImplementation(ArrayList.class, ListProxyDefaultImpl.class);
061 }
062
063 /**
064 * @see org.kuali.rice.kns.service.XmlObjectSerializer#toXml(java.lang.Object)
065 */
066 public String toXml(Object object) {
067 if ( LOG.isDebugEnabled() ) {
068 LOG.debug( "toXml(" + object + ") : \n" + xstream.toXML(object) );
069 }
070 return xstream.toXML(object);
071 }
072
073 /**
074 * @see org.kuali.rice.kns.service.XmlObjectSerializer#fromXml(java.lang.String)
075 */
076 public Object fromXml(String xml) {
077 if ( LOG.isDebugEnabled() ) {
078 LOG.debug( "fromXml() : \n" + xml );
079 }
080 if ( xml != null ) {
081 xml = xml.replaceAll( "--EnhancerByCGLIB--[0-9a-f]{0,8}", "" );
082 }
083 return xstream.fromXML(xml);
084 }
085
086 public String writeNode(org.w3c.dom.Node node, boolean indent) throws TransformerException {
087 Source source = new DOMSource(node);
088 StringWriter writer = new StringWriter();
089 Result result = new StreamResult(writer);
090 Transformer transformer = TransformerFactory.newInstance().newTransformer();
091 transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
092 if (indent) {
093 transformer.setOutputProperty(OutputKeys.INDENT, "yes");
094 }
095 transformer.transform(source, result);
096 return writer.toString();
097 }
098
099
100 /**
101 * This custom converter only handles proxies for BusinessObjects. List-type proxies are handled by configuring XStream to treat
102 * ListProxyDefaultImpl as ArrayLists (see constructor for this service).
103 */
104 public class ProxyConverter extends ReflectionConverter {
105 public ProxyConverter(Mapper mapper, ReflectionProvider reflectionProvider) {
106 super(mapper, reflectionProvider);
107 }
108 public boolean canConvert(Class clazz) {
109 return clazz.getName().contains("CGLIB");
110 }
111
112 public void marshal(Object obj, HierarchicalStreamWriter writer, MarshallingContext context) {
113 super.marshal(getPersistenceService().resolveProxy(obj), writer, context);
114 }
115
116 // we shouldn't need an unmarshal method because all proxy metadata is taken out of the XML, so we'll reserialize as a base BO.
117 }
118
119 public class ProxyAwareJavaReflectionProvider extends PureJavaReflectionProvider {
120
121 public ProxyAwareJavaReflectionProvider() {
122 super();
123 }
124 /**
125 * @see com.thoughtworks.xstream.converters.reflection.PureJavaReflectionProvider#visitSerializableFields(java.lang.Object, com.thoughtworks.xstream.converters.reflection.ReflectionProvider.Visitor)
126 */
127 @Override
128 public void visitSerializableFields(Object object, Visitor visitor) {
129 for (Iterator iterator = fieldDictionary.serializableFieldsFor(object.getClass()); iterator.hasNext();) {
130 Field field = (Field) iterator.next();
131 if (!fieldModifiersSupported(field)) {
132 continue;
133 }
134 validateFieldAccess(field);
135 Object value = null;
136 try {
137 value = field.get(object);
138 if (value != null && ProxyHelper.isProxy(value)) {
139 value = getPersistenceService().resolveProxy(value);
140 }
141 } catch (IllegalArgumentException e) {
142 throw new ObjectAccessException("Could not get field " + field.getClass() + "." + field.getName(), e);
143 } catch (IllegalAccessException e) {
144 throw new ObjectAccessException("Could not get field " + field.getClass() + "." + field.getName(), e);
145 }
146 visitor.visit(field.getName(), field.getType(), field.getDeclaringClass(), value);
147 }
148 }
149
150 }
151
152 public PersistenceService getPersistenceService() {
153 if ( persistenceService == null ) {
154 persistenceService = KNSServiceLocator.getPersistenceService();
155 }
156 return persistenceService;
157 }
158
159 }