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012// ***************************************************************************************************************************
013package org.apache.juneau.swap;
014
015import org.apache.juneau.*;
016
017/**
018 * Abstract subclass for object swaps that swap objects for strings.
019 *
020 * <h5 class='section'>Example:</h5>
021 * <p class='bjava'>
022 *    <jc>// A swap that converts byte arrays to BASE64-encoded strings.</jc>
023 *    <jk>public class</jk> ByteArrayBase64Swap <jk>extends</jk> StringSwap&lt;<jk>byte</jk>[]&gt; {
024 *
025 *       <ja>@Override</ja>
026 *       <jk>public</jk> String swap(BeanSession <jv>session</jv>, <jk>byte</jk>[] <jv>bytes</jv>) <jk>throws</jk> Exception {
027 *          <jk>return</jk> StringUtils.<jsm>base64Encode</jsm>(<jv>bytes</jv>);
028 *       }
029 *
030 *       <ja>@Override</ja>
031 *       <jk>public byte</jk>[] unswap(BeanSession <jv>session</jv>, String <jv>string</jv>, ClassMeta&lt;?&gt; <jv>hint</jv>) <jk>throws</jk> Exception {
032 *          <jk>return</jk> StringUtils.<jsm>base64Decode</jsm>(<jv>string</jv>);
033 *       }
034 *    }
035 *
036 *    <jc>// Use it to serialize a byte array.</jc>
037 *    WriterSerializer <jv>serializer</jv> = JsonSerializer.<jsm>create</jsm>().simple().swaps(ByteArrayBase64Swap.<jk>class</jk>).build();
038 *    String <jv>json</jv> = <jv>serializer</jv>.serialize(<jk>new byte</jk>[] {1,2,3});  <jc>// Produces "'AQID'"</jc>
039 * </p>
040 *
041 * <h5 class='section'>See Also:</h5><ul>
042 *    <li class='link'><a class="doclink" href="../../../../index.html#jm.Swaps">Swaps</a>
043 * </ul>
044 *
045 * @param <T> The normal form of the class.
046 */
047public abstract class StringSwap<T> extends ObjectSwap<T,String> {
048
049   /**
050    * Constructor.
051    */
052   protected StringSwap() {
053      super();
054   }
055
056   /**
057    * Constructor for when the normal and transformed classes are already known.
058    *
059    * @param normalClass The normal class (cannot be serialized).
060    */
061   protected StringSwap(Class<T> normalClass) {
062      super(normalClass, String.class);
063   }
064
065   @Override /* ObjectSwap */
066   public String swap(BeanSession session, T o) throws Exception {
067      return super.swap(session, o);
068   }
069
070   @Override /* ObjectSwap */
071   public T unswap(BeanSession session, String f, ClassMeta<?> hint) throws Exception {
072      return super.unswap(session, f, hint);
073   }
074}