org.apache.juneau.swap.FunctionalSwap Maven / Gradle / Ivy

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// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
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package org.apache.juneau.swap;

import org.apache.juneau.*;
import org.apache.juneau.utils.*;

/**
 * A subclass of {@link ObjectSwap} that allows swap and unswap methods to be defined as functions.
 *
 * 
 * 	// Example
 * 	public class MyBeanSwap extends FunctionalSwap<MyBean,String> {
 * 		public MyBeanSwap() {
 * 			super(MyBean.class, String.class, x -> myStringifyier(x), x -> myDeStringifier(x));
 * 		}
 * 	}
 * 
 *
 * See Also:

 * 	Swaps
 * 
 *
 * @param  The normal form of the class.
 * @param  The swapped form of the class.
 */
public class FunctionalSwap extends ObjectSwap {

	private final ThrowingFunction swapFunction;
	private final ThrowingFunction unswapFunction;

	/**
	 * Constructor.
	 *
	 * @param normalClass The normal class.
	 * @param swappedClass The swapped class.
	 * @param swapFunction The function for converting from normal to swapped.
	 */
	public FunctionalSwap(Class normalClass, Class swappedClass, ThrowingFunction swapFunction) {
		this(normalClass, swappedClass, swapFunction, null);
	}

	/**
	 * Constructor.
	 *
	 * @param normalClass The normal class.
	 * @param swappedClass The swapped class.
	 * @param swapFunction The function for converting from normal to swapped.
	 * @param unswapFunction The function for converting swapped to normal.
	 */
	public FunctionalSwap(Class normalClass, Class swappedClass, ThrowingFunction swapFunction, ThrowingFunction unswapFunction) {
		super(normalClass, swappedClass);
		this.swapFunction = swapFunction;
		this.unswapFunction = unswapFunction;
	}

	@Override
	public S swap(BeanSession session, T o, String template) throws Exception {
		if (swapFunction == null)
			return super.swap(session, o, template);
		return swapFunction.applyThrows(o);
	}

	@Override
	public T unswap(BeanSession session, S f, ClassMeta hint, String template) throws Exception {
		if (unswapFunction == null)
			return super.unswap(session, f, hint, template);
		return unswapFunction.applyThrows(f);
	}
}