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