001 /**
002 * Copyright 2005-2012 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 package org.kuali.rice.krad.service.impl;
017
018 import com.thoughtworks.xstream.XStream;
019 import com.thoughtworks.xstream.converters.MarshallingContext;
020 import com.thoughtworks.xstream.converters.reflection.ObjectAccessException;
021 import com.thoughtworks.xstream.converters.reflection.PureJavaReflectionProvider;
022 import com.thoughtworks.xstream.converters.reflection.ReflectionConverter;
023 import com.thoughtworks.xstream.converters.reflection.ReflectionProvider;
024 import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
025 import com.thoughtworks.xstream.mapper.Mapper;
026 import org.apache.commons.logging.Log;
027 import org.apache.commons.logging.LogFactory;
028 import org.apache.ojb.broker.core.proxy.ListProxyDefaultImpl;
029 import org.kuali.rice.krad.service.KRADServiceLocator;
030 import org.kuali.rice.krad.service.PersistenceService;
031 import org.kuali.rice.krad.service.XmlObjectSerializerService;
032
033 import java.lang.reflect.Field;
034 import java.util.ArrayList;
035 import java.util.Iterator;
036
037
038 /**
039 * This class is the service implementation for the XmlObjectSerializer structure. This is the default implementation that gets
040 * delivered with Kuali. It utilizes the XStream open source libraries and framework.
041 *
042 *
043 */
044 public class XmlObjectSerializerServiceImpl implements XmlObjectSerializerService {
045 private static final Log LOG = LogFactory.getLog(XmlObjectSerializerServiceImpl.class);
046
047 private PersistenceService persistenceService;
048
049 private XStream xstream;
050
051 public XmlObjectSerializerServiceImpl() {
052 xstream = new XStream(new ProxyAwareJavaReflectionProvider());
053
054 // See http://xstream.codehaus.org/faq.html#Serialization_CGLIB
055 // To use a newer version of XStream we may need to do something like this:
056 // xstream = new XStream() {
057 //
058 // @Override
059 // public ReflectionProvider getReflectionProvider() {
060 // return new ProxyAwareJavaReflectionProvider();
061 // }
062 //
063 // protected MapperWrapper wrapMapper(MapperWrapper next) {
064 // return new CGLIBMapper(next);
065 // }
066 // };
067 // xstream.registerConverter(new CGLIBEnhancedConverter(xstream.getMapper(), xstream.getReflectionProvider()));
068
069 xstream.registerConverter(new ProxyConverter(xstream.getMapper(), xstream.getReflectionProvider() ));
070 xstream.addDefaultImplementation(ArrayList.class, ListProxyDefaultImpl.class);
071 }
072
073 /**
074 * @see org.kuali.rice.krad.service.XmlObjectSerializer#toXml(java.lang.Object)
075 */
076 public String toXml(Object object) {
077 if ( LOG.isDebugEnabled() ) {
078 LOG.debug( "toXml(" + object + ") : \n" + xstream.toXML(object) );
079 }
080 return xstream.toXML(object);
081 }
082
083 /**
084 * @see org.kuali.rice.krad.service.XmlObjectSerializer#fromXml(java.lang.String)
085 */
086 public Object fromXml(String xml) {
087 if ( LOG.isDebugEnabled() ) {
088 LOG.debug( "fromXml() : \n" + xml );
089 }
090 if ( xml != null ) {
091 xml = xml.replaceAll( "--EnhancerByCGLIB--[0-9a-f]{0,8}", "" );
092 }
093 return xstream.fromXML(xml);
094 }
095
096 /**
097 * This custom converter only handles proxies for BusinessObjects. List-type proxies are handled by configuring XStream to treat
098 * ListProxyDefaultImpl as ArrayLists (see constructor for this service).
099 */
100 public class ProxyConverter extends ReflectionConverter {
101 public ProxyConverter(Mapper mapper, ReflectionProvider reflectionProvider) {
102 super(mapper, reflectionProvider);
103 }
104
105 @Override
106 // since the ReflectionConverter supertype defines canConvert without using a parameterized Class type, we must declare
107 // the overridden version the same way
108 @SuppressWarnings("unchecked")
109 public boolean canConvert(Class clazz) {
110 return clazz.getName().contains("CGLIB");
111 }
112
113 @Override
114 public void marshal(Object obj, HierarchicalStreamWriter writer, MarshallingContext context) {
115 super.marshal(getPersistenceService().resolveProxy(obj), writer, context);
116 }
117
118 // 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.
119 }
120
121 public class ProxyAwareJavaReflectionProvider extends PureJavaReflectionProvider {
122
123 public ProxyAwareJavaReflectionProvider() {
124 super();
125 }
126 /**
127 * @see com.thoughtworks.xstream.converters.reflection.PureJavaReflectionProvider#visitSerializableFields(java.lang.Object, com.thoughtworks.xstream.converters.reflection.ReflectionProvider.Visitor)
128 */
129 @Override
130 public void visitSerializableFields(Object object, Visitor visitor) {
131 for (Iterator iterator = fieldDictionary.serializableFieldsFor(object.getClass()); iterator.hasNext();) {
132 Field field = (Field) iterator.next();
133 if (!fieldModifiersSupported(field)) {
134 continue;
135 }
136 validateFieldAccess(field);
137 Object value = null;
138 try {
139 value = field.get(object);
140 if (value != null && getPersistenceService().isProxied(value)) {
141 value = getPersistenceService().resolveProxy(value);
142 }
143 } catch (IllegalArgumentException e) {
144 throw new ObjectAccessException("Could not get field " + field.getClass() + "." + field.getName(), e);
145 } catch (IllegalAccessException e) {
146 throw new ObjectAccessException("Could not get field " + field.getClass() + "." + field.getName(), e);
147 }
148 visitor.visit(field.getName(), field.getType(), field.getDeclaringClass(), value);
149 }
150 }
151
152 }
153
154 public PersistenceService getPersistenceService() {
155 if ( persistenceService == null ) {
156 persistenceService = KRADServiceLocator.getPersistenceService();
157 }
158 return persistenceService;
159 }
160
161 }