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.transform; 014 015import static org.apache.juneau.internal.CollectionUtils.*; 016import static org.apache.juneau.internal.ClassUtils.*; 017 018import java.lang.reflect.*; 019import java.util.*; 020 021import org.apache.juneau.*; 022import org.apache.juneau.annotation.*; 023import org.apache.juneau.parser.*; 024import org.apache.juneau.reflect.*; 025import org.apache.juneau.serializer.*; 026 027/** 028 * A dynamic POJO swap based on reflection of a Java class that converts POJOs to serializable objects. 029 * 030 * <p> 031 * Looks for methods on the class that can be called to swap-in surrogate objects before serialization and swap-out 032 * surrogate objects after parsing. 033 * 034 * <h5 class='figure'>Valid surrogate objects</h5> 035 * <ul> 036 * <li class='jc'>{@link String} 037 * <li class='jc'>{@link Number} 038 * <li class='jc'>{@link Boolean} 039 * <li class='jc'>{@link Map} 040 * <li class='jc'>{@link Collection} 041 * </ul> 042 * 043 * <h5 class='figure'>Valid swap methods (S = Swapped type)</h5> 044 * <ul> 045 * <li class='jm'><c><jk>public</jk> S swap()</c> 046 * <li class='jm'><c><jk>public</jk> S swap(BeanSession)</c> 047 * <li class='jm'><c><jk>public</jk> S toObject()</c> 048 * <li class='jm'><c><jk>public</jk> S toObject(BeanSession)</c> 049 * </ul> 050 * 051 * <h5 class='figure'>Valid unswap methods (N = Normal type, S = Swapped type)</h5> 052 * <ul> 053 * <li class='jm'><c><jk>public static</jk> N unswap(S)</c> 054 * <li class='jm'><c><jk>public static</jk> N unswap(BeanSession, S)</c> 055 * <li class='jm'><c><jk>public static</jk> N fromObject(S)</c> 056 * <li class='jm'><c><jk>public static</jk> N fromObject(BeanSession, S)</c> 057 * <li class='jm'><c><jk>public static</jk> N create(S)</c> 058 * <li class='jm'><c><jk>public static</jk> N create(BeanSession, S)</c> 059 * <li class='jm'><c><jk>public</jk> N(S)</c> 060 * </ul> 061 * 062 * <p> 063 * Classes are ignored if any of the following are true: 064 * <ul> 065 * <li>Classes annotated with {@link BeanIgnore @BeanIgnore}. 066 * <li>Non-static member classes. 067 * </ul> 068 * 069 * <p> 070 * Members/constructors are ignored if any of the following are true: 071 * <ul> 072 * <li>Members/constructors annotated with {@link BeanIgnore @BeanIgnore}. 073 * <li>Deprecated members/constructors. 074 * </ul> 075 * 076 * @param <T> The normal class type. 077 */ 078public class AutoObjectSwap<T> extends PojoSwap<T,Object> { 079 080 private static final Set<String> 081 SWAP_METHOD_NAMES = newUnmodifiableHashSet("swap", "toObject"), 082 UNSWAP_METHOD_NAMES = newUnmodifiableHashSet("unswap", "create", "fromObject"); 083 084 /** 085 * Inspects the specified class and returns a swap of this type if possible. 086 * 087 * @param ci The class to return a swap on. 088 * @return A POJO swap instance, or <jk>null</jk> if one could not be created. 089 */ 090 @SuppressWarnings({ "rawtypes" }) 091 public static PojoSwap<?,?> find(ClassInfo ci) { 092 093 if (shouldIgnore(ci)) 094 return null; 095 096 // Find swap() method if present. 097 for (MethodInfo m : ci.getPublicMethods()) { 098 if (isSwapMethod(m)) { 099 100 ClassInfo rt = m.getReturnType(); 101 102 for (MethodInfo m2 : ci.getPublicMethods()) 103 if (isUnswapMethod(m2, ci, rt)) 104 return new AutoObjectSwap(ci, m, m2, null); 105 106 for (ConstructorInfo cs : ci.getPublicConstructors()) 107 if (isUnswapConstructor(cs, rt)) 108 return new AutoObjectSwap(ci, m, null, cs); 109 110 return new AutoObjectSwap(ci, m, null, null); 111 } 112 } 113 114 return null; 115 } 116 117 private static boolean shouldIgnore(ClassInfo ci) { 118 return 119 ci.hasAnnotation(BeanIgnore.class) 120 || ci.isNonStaticMemberClass(); 121 } 122 123 private static boolean isSwapMethod(MethodInfo mi) { 124 return 125 mi.isNotDeprecated() 126 && mi.isNotStatic() 127 && mi.hasName(SWAP_METHOD_NAMES) 128 && mi.hasFuzzyParamTypes(BeanSession.class) 129 && ! mi.hasAnnotation(BeanIgnore.class); 130 } 131 132 private static boolean isUnswapMethod(MethodInfo mi, ClassInfo ci, ClassInfo rt) { 133 return 134 mi.isNotDeprecated() 135 && mi.isStatic() 136 && mi.hasName(UNSWAP_METHOD_NAMES) 137 && mi.hasFuzzyParamTypes(BeanSession.class, rt.inner()) 138 && mi.hasReturnTypeParent(ci) 139 && ! mi.hasAnnotation(BeanIgnore.class); 140 } 141 142 private static boolean isUnswapConstructor(ConstructorInfo cs, ClassInfo rt) { 143 return 144 cs.isNotDeprecated() 145 && cs.hasParamTypeParents(rt) 146 && ! cs.hasAnnotation(BeanIgnore.class); 147 } 148 149 //------------------------------------------------------------------------------------------------------------------ 150 151 private final Method swapMethod, unswapMethod; 152 private final Constructor<?> unswapConstructor; 153 154 private AutoObjectSwap(ClassInfo ci, MethodInfo swapMethod, MethodInfo unswapMethod, ConstructorInfo unswapConstructor) { 155 super(ci.inner(), swapMethod.inner().getReturnType()); 156 this.swapMethod = swapMethod.inner(); 157 this.unswapMethod = unswapMethod == null ? null : unswapMethod.inner(); 158 this.unswapConstructor = unswapConstructor == null ? null : unswapConstructor.inner(); 159 } 160 161 @Override /* PojoSwap */ 162 public Object swap(BeanSession session, Object o) throws SerializeException { 163 try { 164 return swapMethod.invoke(o, getMatchingArgs(swapMethod.getParameterTypes(), session)); 165 } catch (Exception e) { 166 throw SerializeException.create(e); 167 } 168 } 169 170 @SuppressWarnings("unchecked") 171 @Override /* PojoSwap */ 172 public T unswap(BeanSession session, Object f, ClassMeta<?> hint) throws ParseException { 173 try { 174 if (unswapMethod != null) 175 return (T)unswapMethod.invoke(null, getMatchingArgs(unswapMethod.getParameterTypes(), session, f)); 176 if (unswapConstructor != null) 177 return (T)unswapConstructor.newInstance(f); 178 return super.unswap(session, f, hint); 179 } catch (Exception e) { 180 throw ParseException.create(e); 181 } 182 } 183}