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.ClassUtils.*;
016
017import java.lang.reflect.*;
018import java.util.*;
019
020import org.apache.juneau.*;
021import org.apache.juneau.annotation.*;
022import org.apache.juneau.collections.*;
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 = ASet.unmodifiable("swap", "toObject"),
082      UNSWAP_METHOD_NAMES = ASet.unmodifiable("unswap", "create", "fromObject", "of");
083
084   /**
085    * Inspects the specified class and returns a swap of this type if possible.
086    *
087    * @param bc The bean context to use for looking up annotations.
088    * @param ci The class to return a swap on.
089    * @return A POJO swap instance, or <jk>null</jk> if one could not be created.
090    */
091   @SuppressWarnings({ "rawtypes" })
092   public static PojoSwap<?,?> find(BeanContext bc, ClassInfo ci) {
093
094      if (shouldIgnore(bc, ci))
095         return null;
096
097      // Find swap() method if present.
098      for (MethodInfo m : ci.getAllMethods()) {
099         if (isSwapMethod(bc, m)) {
100
101            ClassInfo rt = m.getReturnType();
102
103            for (MethodInfo m2 : ci.getAllMethods())
104               if (isUnswapMethod(bc, m2, ci, rt))
105                  return new AutoObjectSwap(bc, ci, m, m2, null);
106
107            for (ConstructorInfo cs : ci.getDeclaredConstructors())
108               if (isUnswapConstructor(bc, cs, rt))
109                  return new AutoObjectSwap(bc, ci, m, null, cs);
110
111            return new AutoObjectSwap(bc, ci, m, null, null);
112         }
113      }
114
115      return null;
116   }
117
118   private static boolean shouldIgnore(BeanContext bc, ClassInfo ci) {
119      return
120         bc.hasAnnotation(BeanIgnore.class, ci)
121         || ci.isNonStaticMemberClass();
122   }
123
124   private static boolean isSwapMethod(BeanContext bc, MethodInfo mi) {
125      return
126         mi.isNotDeprecated()
127         && mi.isNotStatic()
128         && mi.isVisible(bc.getBeanMethodVisibility())
129         && mi.hasName(SWAP_METHOD_NAMES)
130         && mi.hasFuzzyParamTypes(BeanSession.class)
131         && ! bc.hasAnnotation(BeanIgnore.class, mi);
132   }
133
134   private static boolean isUnswapMethod(BeanContext bc, MethodInfo mi, ClassInfo ci, ClassInfo rt) {
135      return
136         mi.isNotDeprecated()
137         && mi.isStatic()
138         && mi.isVisible(bc.getBeanMethodVisibility())
139         && mi.hasName(UNSWAP_METHOD_NAMES)
140         && mi.hasFuzzyParamTypes(BeanSession.class, rt.inner())
141         && mi.hasReturnTypeParent(ci)
142         && ! bc.hasAnnotation(BeanIgnore.class, mi);
143   }
144
145   private static boolean isUnswapConstructor(BeanContext bc, ConstructorInfo cs, ClassInfo rt) {
146      return
147         cs.isNotDeprecated()
148         && cs.isVisible(bc.getBeanConstructorVisibility())
149         && cs.hasMatchingParamTypes(rt)
150         && ! bc.hasAnnotation(BeanIgnore.class, cs);
151   }
152
153   //------------------------------------------------------------------------------------------------------------------
154
155   private final Method swapMethod, unswapMethod;
156   private final Constructor<?> unswapConstructor;
157
158   private AutoObjectSwap(BeanContext bc, ClassInfo ci, MethodInfo swapMethod, MethodInfo unswapMethod, ConstructorInfo unswapConstructor) {
159      super(ci.inner(), swapMethod.inner().getReturnType());
160      this.swapMethod = bc.getBeanMethodVisibility().transform(swapMethod.inner());
161      this.unswapMethod = unswapMethod == null ? null : bc.getBeanMethodVisibility().transform(unswapMethod.inner());
162      this.unswapConstructor = unswapConstructor == null ? null : bc.getBeanConstructorVisibility().transform(unswapConstructor.inner());
163   }
164
165   @Override /* PojoSwap */
166   public Object swap(BeanSession session, Object o) throws SerializeException {
167      try {
168         return swapMethod.invoke(o, getMatchingArgs(swapMethod.getParameterTypes(), session));
169      } catch (Exception e) {
170         throw SerializeException.create(e);
171      }
172   }
173
174   @SuppressWarnings("unchecked")
175   @Override /* PojoSwap */
176   public T unswap(BeanSession session, Object f, ClassMeta<?> hint) throws ParseException {
177      try {
178         if (unswapMethod != null)
179            return (T)unswapMethod.invoke(null, getMatchingArgs(unswapMethod.getParameterTypes(), session, f));
180         if (unswapConstructor != null)
181            return (T)unswapConstructor.newInstance(f);
182         return super.unswap(session, f, hint);
183      } catch (Exception e) {
184         throw ParseException.create(e);
185      }
186   }
187}