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16 package org.apache.ibatis.executor.loader.javassist;
17
18 import java.lang.reflect.Method;
19 import java.util.List;
20 import java.util.Map;
21 import java.util.Properties;
22 import java.util.Set;
23
24 import javassist.util.proxy.MethodHandler;
25 import javassist.util.proxy.Proxy;
26 import javassist.util.proxy.ProxyFactory;
27
28 import org.apache.ibatis.executor.ExecutorException;
29 import org.apache.ibatis.executor.loader.AbstractEnhancedDeserializationProxy;
30 import org.apache.ibatis.executor.loader.AbstractSerialStateHolder;
31 import org.apache.ibatis.executor.loader.ResultLoaderMap;
32 import org.apache.ibatis.executor.loader.WriteReplaceInterface;
33 import org.apache.ibatis.io.Resources;
34 import org.apache.ibatis.logging.Log;
35 import org.apache.ibatis.logging.LogFactory;
36 import org.apache.ibatis.reflection.ExceptionUtil;
37 import org.apache.ibatis.reflection.factory.ObjectFactory;
38 import org.apache.ibatis.reflection.property.PropertyCopier;
39 import org.apache.ibatis.reflection.property.PropertyNamer;
40 import org.apache.ibatis.session.Configuration;
41
42
43
44
45 public class JavassistProxyFactory implements org.apache.ibatis.executor.loader.ProxyFactory {
46
47 private static final Log log = LogFactory.getLog(JavassistProxyFactory.class);
48 private static final String FINALIZE_METHOD = "finalize";
49 private static final String WRITE_REPLACE_METHOD = "writeReplace";
50
51 public JavassistProxyFactory() {
52 try {
53 Resources.classForName("javassist.util.proxy.ProxyFactory");
54 } catch (Throwable e) {
55 throw new IllegalStateException("Cannot enable lazy loading because Javassist is not available. Add Javassist to your classpath.", e);
56 }
57 }
58
59 @Override
60 public Object createProxy(Object target, ResultLoaderMap lazyLoader, Configuration configuration, ObjectFactory objectFactory, List<Class<?>> constructorArgTypes, List<Object> constructorArgs) {
61 return EnhancedResultObjectProxyImpl.createProxy(target, lazyLoader, configuration, objectFactory, constructorArgTypes, constructorArgs);
62 }
63
64 public Object createDeserializationProxy(Object target, Map<String, ResultLoaderMap.LoadPair> unloadedProperties, ObjectFactory objectFactory, List<Class<?>> constructorArgTypes, List<Object> constructorArgs) {
65 return EnhancedDeserializationProxyImpl.createProxy(target, unloadedProperties, objectFactory, constructorArgTypes, constructorArgs);
66 }
67
68 @Override
69 public void setProperties(Properties properties) {
70
71 }
72
73 static Object crateProxy(Class<?> type, MethodHandler callback, List<Class<?>> constructorArgTypes, List<Object> constructorArgs) {
74
75 ProxyFactory enhancer = new ProxyFactory();
76 enhancer.setSuperclass(type);
77
78 try {
79 type.getDeclaredMethod(WRITE_REPLACE_METHOD);
80
81 if (log.isDebugEnabled()) {
82 log.debug(WRITE_REPLACE_METHOD + " method was found on bean " + type + ", make sure it returns this");
83 }
84 } catch (NoSuchMethodException e) {
85 enhancer.setInterfaces(new Class[]{WriteReplaceInterface.class});
86 } catch (SecurityException e) {
87
88 }
89
90 Object enhanced = null;
91 Class<?>[] typesArray = constructorArgTypes.toArray(new Class[constructorArgTypes.size()]);
92 Object[] valuesArray = constructorArgs.toArray(new Object[constructorArgs.size()]);
93 try {
94 enhanced = enhancer.create(typesArray, valuesArray);
95 } catch (Exception e) {
96 throw new ExecutorException("Error creating lazy proxy. Cause: " + e, e);
97 }
98 ((Proxy) enhanced).setHandler(callback);
99 return enhanced;
100 }
101
102 private static class EnhancedResultObjectProxyImpl implements MethodHandler {
103
104 private Class<?> type;
105 private ResultLoaderMap lazyLoader;
106 private boolean aggressive;
107 private Set<String> lazyLoadTriggerMethods;
108 private ObjectFactory objectFactory;
109 private List<Class<?>> constructorArgTypes;
110 private List<Object> constructorArgs;
111
112 private EnhancedResultObjectProxyImpl(Class<?> type, ResultLoaderMap lazyLoader, Configuration configuration, ObjectFactory objectFactory, List<Class<?>> constructorArgTypes, List<Object> constructorArgs) {
113 this.type = type;
114 this.lazyLoader = lazyLoader;
115 this.aggressive = configuration.isAggressiveLazyLoading();
116 this.lazyLoadTriggerMethods = configuration.getLazyLoadTriggerMethods();
117 this.objectFactory = objectFactory;
118 this.constructorArgTypes = constructorArgTypes;
119 this.constructorArgs = constructorArgs;
120 }
121
122 public static Object createProxy(Object target, ResultLoaderMap lazyLoader, Configuration configuration, ObjectFactory objectFactory, List<Class<?>> constructorArgTypes, List<Object> constructorArgs) {
123 final Class<?> type = target.getClass();
124 EnhancedResultObjectProxyImpl callback = new EnhancedResultObjectProxyImpl(type, lazyLoader, configuration, objectFactory, constructorArgTypes, constructorArgs);
125 Object enhanced = crateProxy(type, callback, constructorArgTypes, constructorArgs);
126 PropertyCopier.copyBeanProperties(type, target, enhanced);
127 return enhanced;
128 }
129
130 @Override
131 public Object invoke(Object enhanced, Method method, Method methodProxy, Object[] args) throws Throwable {
132 final String methodName = method.getName();
133 try {
134 synchronized (lazyLoader) {
135 if (WRITE_REPLACE_METHOD.equals(methodName)) {
136 Object original = null;
137 if (constructorArgTypes.isEmpty()) {
138 original = objectFactory.create(type);
139 } else {
140 original = objectFactory.create(type, constructorArgTypes, constructorArgs);
141 }
142 PropertyCopier.copyBeanProperties(type, enhanced, original);
143 if (lazyLoader.size() > 0) {
144 return new JavassistSerialStateHolder(original, lazyLoader.getProperties(), objectFactory, constructorArgTypes, constructorArgs);
145 } else {
146 return original;
147 }
148 } else {
149 if (lazyLoader.size() > 0 && !FINALIZE_METHOD.equals(methodName)) {
150 if (aggressive || lazyLoadTriggerMethods.contains(methodName)) {
151 lazyLoader.loadAll();
152 } else if (PropertyNamer.isProperty(methodName)) {
153 final String property = PropertyNamer.methodToProperty(methodName);
154 if (lazyLoader.hasLoader(property)) {
155 lazyLoader.load(property);
156 }
157 }
158 }
159 }
160 }
161 return methodProxy.invoke(enhanced, args);
162 } catch (Throwable t) {
163 throw ExceptionUtil.unwrapThrowable(t);
164 }
165 }
166 }
167
168 private static class EnhancedDeserializationProxyImpl extends AbstractEnhancedDeserializationProxy implements MethodHandler {
169
170 private EnhancedDeserializationProxyImpl(Class<?> type, Map<String, ResultLoaderMap.LoadPair> unloadedProperties, ObjectFactory objectFactory,
171 List<Class<?>> constructorArgTypes, List<Object> constructorArgs) {
172 super(type, unloadedProperties, objectFactory, constructorArgTypes, constructorArgs);
173 }
174
175 public static Object createProxy(Object target, Map<String, ResultLoaderMap.LoadPair> unloadedProperties, ObjectFactory objectFactory,
176 List<Class<?>> constructorArgTypes, List<Object> constructorArgs) {
177 final Class<?> type = target.getClass();
178 EnhancedDeserializationProxyImpl callback = new EnhancedDeserializationProxyImpl(type, unloadedProperties, objectFactory, constructorArgTypes, constructorArgs);
179 Object enhanced = crateProxy(type, callback, constructorArgTypes, constructorArgs);
180 PropertyCopier.copyBeanProperties(type, target, enhanced);
181 return enhanced;
182 }
183
184 @Override
185 public Object invoke(Object enhanced, Method method, Method methodProxy, Object[] args) throws Throwable {
186 final Object o = super.invoke(enhanced, method, args);
187 return (o instanceof AbstractSerialStateHolder) ? o : methodProxy.invoke(o, args);
188 }
189
190 @Override
191 protected AbstractSerialStateHolder newSerialStateHolder(Object userBean, Map<String, ResultLoaderMap.LoadPair> unloadedProperties, ObjectFactory objectFactory,
192 List<Class<?>> constructorArgTypes, List<Object> constructorArgs) {
193 return new JavassistSerialStateHolder(userBean, unloadedProperties, objectFactory, constructorArgTypes, constructorArgs);
194 }
195 }
196 }