001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
003// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
005// * with the License.  You may obtain a copy of the License at                                                              *
006// *                                                                                                                         *
007// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
008// *                                                                                                                         *
009// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an  *
010// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the        *
011// * specific language governing permissions and limitations under the License.                                              *
012// ***************************************************************************************************************************
013package org.apache.juneau;
014
015import java.lang.reflect.*;
016import java.util.*;
017
018import org.apache.juneau.json.*;
019import org.apache.juneau.reflect.*;
020
021/**
022 * Provides an {@link InvocationHandler} for creating beans from bean interfaces.
023 *
024 * <p>
025 * If the {@code useInterfaceProxies} setting is enabled in {@link BeanContext}, this is the class that creates
026 * instances of beans from interfaces.
027 *
028 * @param <T> The interface class
029 */
030public class BeanProxyInvocationHandler<T> implements InvocationHandler {
031
032   private final BeanMeta<T> meta;                 // The BeanMeta for this instance
033   private Map<String, Object> beanProps;    // The map of property names to bean property values.
034
035   /**
036    * Constructs with the specified {@link BeanMeta}.
037    *
038    * @param meta The bean meta data.
039    */
040   public BeanProxyInvocationHandler(BeanMeta<T> meta) {
041      this.meta = meta;
042      this.beanProps = new HashMap<>();
043   }
044
045   /**
046    * Implemented to handle the method called.
047    */
048   @Override /* InvocationHandler */
049   public Object invoke(Object proxy, Method method, Object[] args) {
050      MethodInfo mi = MethodInfo.of(method);
051      if (mi.hasName("equals") && mi.hasParamTypes(java.lang.Object.class)) {
052         Object arg = args[0];
053         if (arg == null)
054            return false;
055         if (proxy == arg)
056            return true;
057         if (proxy.getClass() == arg.getClass()) {
058            InvocationHandler ih = Proxy.getInvocationHandler(arg);
059            if (ih instanceof BeanProxyInvocationHandler) {
060               return this.beanProps.equals(((BeanProxyInvocationHandler<?>)ih).beanProps);
061            }
062         }
063         BeanMap<Object> bean = this.meta.ctx.createSession().toBeanMap(arg);
064         return this.beanProps.equals(bean);
065      }
066
067      if (mi.hasName("hashCode") && mi.hasNoParams())
068         return Integer.valueOf(this.beanProps.hashCode());
069
070      if (mi.hasName("toString") && mi.hasNoParams())
071         return SimpleJsonSerializer.DEFAULT.toString(this.beanProps);
072
073      String prop = this.meta.getterProps.get(method);
074      if (prop != null)
075         return this.beanProps.get(prop);
076
077      prop = this.meta.setterProps.get(method);
078      if (prop != null) {
079         this.beanProps.put(prop, args[0]);
080         return null;
081      }
082
083      throw new UnsupportedOperationException("Unsupported bean method.  method=[ " + method + " ]");
084   }
085}