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.marshall.swap.spi;
018
019import org.apache.juneau.commons.function.*;
020import org.apache.juneau.marshall.*;
021
022/**
023 * A subclass of {@link ObjectSwap} that allows swap and unswap methods to be defined as functions.
024 *
025 * <p class='bjava'>
026 *    <jc>// Example</jc>
027 *    <jk>public class</jk> MyBeanSwap <jk>extends</jk> FunctionalSwap&lt;MyBean,String&gt; {
028 *       <jk>public</jk> MyBeanSwap() {
029 *          <jk>super</jk>(MyBean.<jk>class</jk>, String.<jk>class</jk>, <jv>x</jv> -&gt; <jsm>myStringifyier</jsm>(<jv>x</jv>), <jv>x</jv> -&gt; <jsm>myDeStringifier</jsm>(<jv>x</jv>));
030 *       }
031 *    }
032 * </p>
033 *
034 * <h5 class='section'>See Also:</h5><ul>
035 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/Swaps">Swap</a>
036 * </ul>
037 *
038 * @param <T> The normal form of the class.
039 * @param <S> The swapped form of the class.
040 */
041public class FunctionalSwap<T,S> extends ObjectSwap<T,S> {
042
043   private final ThrowingFunction<T,S> swapFunction;
044   private final ThrowingFunction<S,T> unswapFunction;
045
046   /**
047    * Constructor.
048    *
049    * @param normalClass The normal class.
050    * @param swappedClass The swapped class.
051    * @param swapFunction The function for converting from normal to swapped.
052    */
053   public FunctionalSwap(Class<T> normalClass, Class<S> swappedClass, ThrowingFunction<T,S> swapFunction) {
054      this(normalClass, swappedClass, swapFunction, null);
055   }
056
057   /**
058    * Constructor.
059    *
060    * @param normalClass The normal class.
061    * @param swappedClass The swapped class.
062    * @param swapFunction The function for converting from normal to swapped.
063    * @param unswapFunction
064    *    The function for converting swapped to normal.
065    *    Can be <jk>null</jk> if this swap is serialize-only (calling {@link #unswap(MarshallingSession, Object, ClassMeta, String)} then throws a {@link org.apache.juneau.marshall.parser.ParseException}).
066    */
067   public FunctionalSwap(Class<T> normalClass, Class<S> swappedClass, ThrowingFunction<T,S> swapFunction, ThrowingFunction<S,T> unswapFunction) {
068      super(normalClass, swappedClass);
069      this.swapFunction = swapFunction;
070      this.unswapFunction = unswapFunction;
071   }
072
073   @Override
074   public S swap(MarshallingSession session, T o, String template) throws Exception {
075      if (swapFunction == null)
076         return super.swap(session, o, template);
077      return swapFunction.applyThrows(o);
078   }
079
080   @Override
081   public T unswap(MarshallingSession session, S f, ClassMeta<?> hint, String template) throws Exception {
082      if (unswapFunction == null)
083         return super.unswap(session, f, hint, template);
084      return unswapFunction.applyThrows(f);
085   }
086}