001/**
002 * Copyright 2005-2016 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 */
016package org.kuali.rice.krad.service.impl;
017
018import com.thoughtworks.xstream.XStream;
019import com.thoughtworks.xstream.converters.MarshallingContext;
020import com.thoughtworks.xstream.converters.SingleValueConverter;
021import com.thoughtworks.xstream.converters.reflection.ObjectAccessException;
022import com.thoughtworks.xstream.converters.reflection.PureJavaReflectionProvider;
023import com.thoughtworks.xstream.converters.reflection.ReflectionConverter;
024import com.thoughtworks.xstream.converters.reflection.ReflectionProvider;
025import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
026import com.thoughtworks.xstream.mapper.Mapper;
027import org.apache.commons.logging.Log;
028import org.apache.commons.logging.LogFactory;
029import org.apache.ojb.broker.core.proxy.ListProxyDefaultImpl;
030import org.joda.time.DateTime;
031import org.joda.time.format.ISODateTimeFormat;
032import org.kuali.rice.krad.service.KRADServiceLocator;
033import org.kuali.rice.krad.service.PersistenceService;
034import org.kuali.rice.krad.service.XmlObjectSerializerService;
035import org.kuali.rice.krad.util.DateTimeConverter;
036
037import java.lang.reflect.Field;
038import java.util.ArrayList;
039import java.util.Iterator;
040
041
042/**
043 * This class is the service implementation for the XmlObjectSerializer structure. This is the default implementation that gets
044 * delivered with Kuali. It utilizes the XStream open source libraries and framework.
045 * 
046 * 
047 */
048public class XmlObjectSerializerServiceImpl implements XmlObjectSerializerService {
049        private static final Log LOG = LogFactory.getLog(XmlObjectSerializerServiceImpl.class);
050        
051        private PersistenceService persistenceService;
052        
053        private XStream xstream;
054        
055        public XmlObjectSerializerServiceImpl() {
056                xstream = new XStream(new ProxyAwareJavaReflectionProvider());
057
058        // See http://xstream.codehaus.org/faq.html#Serialization_CGLIB
059        // To use a newer version of XStream we may need to do something like this:
060//        xstream = new XStream() {
061//
062//            @Override
063//            public ReflectionProvider getReflectionProvider() {
064//                return new ProxyAwareJavaReflectionProvider();
065//            }
066//
067//            protected MapperWrapper wrapMapper(MapperWrapper next) {
068//                return new CGLIBMapper(next);
069//            }
070//        };
071//        xstream.registerConverter(new CGLIBEnhancedConverter(xstream.getMapper(), xstream.getReflectionProvider()));
072
073                xstream.registerConverter(new ProxyConverter(xstream.getMapper(), xstream.getReflectionProvider() ));
074                xstream.addDefaultImplementation(ArrayList.class, ListProxyDefaultImpl.class);
075        xstream.registerConverter(new DateTimeConverter());
076        }
077        
078    /**
079     * @see org.kuali.rice.krad.service.XmlObjectSerializer#toXml(java.lang.Object)
080     */
081    public String toXml(Object object) {
082        if ( LOG.isDebugEnabled() ) {
083                LOG.debug( "toXml(" + object + ") : \n" + xstream.toXML(object) );
084        }
085        return xstream.toXML(object);
086    }
087
088    /**
089     * @see org.kuali.rice.krad.service.XmlObjectSerializer#fromXml(java.lang.String)
090     */
091    public Object fromXml(String xml) {
092        if ( LOG.isDebugEnabled() ) {
093                LOG.debug( "fromXml() : \n" + xml );
094        }
095        if ( xml != null ) {
096                xml = xml.replaceAll( "--EnhancerByCGLIB--[0-9a-f]{0,8}", "" );
097        }
098        return xstream.fromXML(xml);
099    }
100
101    /**
102     * This custom converter only handles proxies for BusinessObjects.  List-type proxies are handled by configuring XStream to treat
103     * ListProxyDefaultImpl as ArrayLists (see constructor for this service). 
104     */
105    public class ProxyConverter extends ReflectionConverter {
106        public ProxyConverter(Mapper mapper, ReflectionProvider reflectionProvider) {
107            super(mapper, reflectionProvider);
108        }
109        
110        @Override
111        // since the ReflectionConverter supertype defines canConvert without using a parameterized Class type, we must declare
112        // the overridden version the same way
113        @SuppressWarnings("unchecked")
114        public boolean canConvert(Class clazz) {
115            return clazz.getName().contains("CGLIB");
116        }
117
118        @Override
119        public void marshal(Object obj, HierarchicalStreamWriter writer, MarshallingContext context) {
120            super.marshal(getPersistenceService().resolveProxy(obj), writer, context);
121        }
122        
123        // 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. 
124    }
125    
126    public class ProxyAwareJavaReflectionProvider extends PureJavaReflectionProvider {
127
128        public ProxyAwareJavaReflectionProvider() {
129                super();
130        }
131        /**
132         * @see com.thoughtworks.xstream.converters.reflection.PureJavaReflectionProvider#visitSerializableFields(java.lang.Object, com.thoughtworks.xstream.converters.reflection.ReflectionProvider.Visitor)
133         */
134        @Override
135        public void visitSerializableFields(Object object, Visitor visitor) {
136            for (Iterator iterator = fieldDictionary.serializableFieldsFor(object.getClass()); iterator.hasNext();) {
137                Field field = (Field) iterator.next();
138                if (!fieldModifiersSupported(field)) {
139                    continue;
140                }
141                validateFieldAccess(field);
142                Object value = null;
143                try {
144                    value = field.get(object);
145                    if (value != null && getPersistenceService().isProxied(value)) {
146                        value = getPersistenceService().resolveProxy(value);
147                    }
148                } catch (IllegalArgumentException e) {
149                    throw new ObjectAccessException("Could not get field " + field.getClass() + "." + field.getName(), e);
150                } catch (IllegalAccessException e) {
151                    throw new ObjectAccessException("Could not get field " + field.getClass() + "." + field.getName(), e);
152                }
153                visitor.visit(field.getName(), field.getType(), field.getDeclaringClass(), value);
154            }
155        }
156        
157    }
158
159        public PersistenceService getPersistenceService() {
160                if ( persistenceService == null ) {
161                        persistenceService = KRADServiceLocator.getPersistenceService();
162                }
163                return persistenceService;
164        }
165
166}