juneau-core/juneau-marshall/src/main/java/org/apache/juneau/transform/StringSwap.java

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package org.apache.juneau.transform;

import org.apache.juneau.*;

/**
 * Abstract subclass for POJO swaps that swap objects for strings.
 *
 * <h5 class='section'>Example:</h5>
 * <p class='bcode w800'>
 * 	<jc>// A swap that converts byte arrays to BASE64-encoded strings.</jc>
 * 	<jk>public class</jk> ByteArrayBase64Swap <jk>extends</jk> StringSwap&lt;<jk>byte</jk>[]&gt; {
 *
 * 		<ja>@Override</ja>
 * 		<jk>public</jk> String swap(BeanSession session, <jk>byte</jk>[] b) <jk>throws</jk> Exception {
 * 			<jk>return</jk> StringUtils.<jsm>base64Encode</jsm>(b);
 * 		}
 *
 * 		<ja>@Override</ja>
 * 		<jk>public byte</jk>[] unswap(BeanSession session, String s, ClassMeta&lt;?&gt; hint) <jk>throws</jk> Exception {
 * 			<jk>return</jk> StringUtils.<jsm>base64Decode</jsm>(s);
 * 		}
 * 	}
 *
 * 	<jc>// Use it to serialize a byte array.</jc>
 * 	WriterSerializer s = JsonSerializer.<jsm>create</jsm>().simple().pojoSwaps(ByteArrayBase64Swap.<jk>class</jk>).build();
 * 	String json = s.serialize(<jk>new byte</jk>[] {1,2,3});  <jc>// Produces "'AQID'"</jc>
 * </p>
 *
 * @param <T> The normal form of the class.
 */
public abstract class StringSwap<T> extends PojoSwap<T,String> {

	/**
	 * Constructor.
	 */
	protected StringSwap() {
		super();
	}

	/**
	 * Constructor for when the normal and transformed classes are already known.
	 *
	 * @param normalClass The normal class (cannot be serialized).
	 */
	protected StringSwap(Class<T> normalClass) {
		super(normalClass, String.class);
	}

	@Override /* PojoSwap */
	public String swap(BeanSession session, T o) throws Exception {
		return super.swap(session, o);
	}

	@Override /* PojoSwap */
	public T unswap(BeanSession session, String f, ClassMeta<?> hint) throws Exception {
		return super.unswap(session, f, hint);
	}
}