001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.juneau;
018
019import java.lang.reflect.*;
020import java.util.*;
021
022import org.apache.juneau.json.*;
023import org.apache.juneau.reflect.*;
024
025/**
026 * Provides an {@link InvocationHandler} for creating beans from bean interfaces.
027 *
028 * <p>
029 * If the {@code useInterfaceProxies} setting is enabled in {@link BeanContext}, this is the class that creates
030 * instances of beans from interfaces.
031 *
032 * <h5 class='section'>See Also:</h5><ul>
033
034 * </ul>
035 *
036 * @param <T> The interface class
037 */
038public class BeanProxyInvocationHandler<T> implements InvocationHandler {
039
040   private final BeanMeta<T> meta;                 // The BeanMeta for this instance
041   private Map<String, Object> beanProps;    // The map of property names to bean property values.
042
043   /**
044    * Constructs with the specified {@link BeanMeta}.
045    *
046    * @param meta The bean meta data.
047    */
048   public BeanProxyInvocationHandler(BeanMeta<T> meta) {
049      this.meta = meta;
050      this.beanProps = new HashMap<>();
051   }
052
053   /**
054    * Implemented to handle the method called.
055    */
056   @Override /* InvocationHandler */
057   public Object invoke(Object proxy, Method method, Object[] args) {
058      MethodInfo mi = MethodInfo.of(method);
059      if (mi.hasName("equals") && mi.hasParamTypes(java.lang.Object.class)) {
060         Object arg = args[0];
061         if (arg == null)
062            return false;
063         if (proxy == arg)
064            return true;
065         if (proxy.getClass() == arg.getClass()) {
066            InvocationHandler ih = Proxy.getInvocationHandler(arg);
067            if (ih instanceof BeanProxyInvocationHandler) {
068               return this.beanProps.equals(((BeanProxyInvocationHandler<?>)ih).beanProps);
069            }
070         }
071         BeanMap<Object> bean = this.meta.ctx.toBeanMap(arg);
072         return this.beanProps.equals(bean);
073      }
074
075      if (mi.hasName("hashCode") && mi.hasNoParams())
076         return Integer.valueOf(this.beanProps.hashCode());
077
078      if (mi.hasName("toString") && mi.hasNoParams())
079         return Json5Serializer.DEFAULT.toString(this.beanProps);
080
081      String prop = this.meta.getterProps.get(method);
082      if (prop != null)
083         return this.beanProps.get(prop);
084
085      prop = this.meta.setterProps.get(method);
086      if (prop != null) {
087         this.beanProps.put(prop, args[0]);
088         return null;
089      }
090
091      throw new UnsupportedOperationException("Unsupported bean method.  method='"+method+"'");
092   }
093}