| /******************************************************************************* |
| * Copyright (c) 2007, 2010 Oracle. All rights reserved. |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Public License v1.0, which accompanies this distribution |
| * and is available at http://www.eclipse.org/legal/epl-v10.html. |
| * |
| * Contributors: |
| * Oracle - initial API and implementation |
| ******************************************************************************/ |
| package org.eclipse.jpt.common.utility.internal; |
| |
| import java.io.Serializable; |
| |
| /** |
| * Used by various "pluggable" classes to transform objects |
| * in both directions. |
| * |
| * If anyone can come up with a better class name |
| * and/or method name, I would love to hear it. ~bjv |
| */ |
| public interface BidiTransformer<T1, T2> extends Transformer<T1, T2> { |
| |
| /** |
| * Return the "reverse-transformed" object. |
| * The semantics of "reverse-transform" is determined by the |
| * contract between the client and the server. |
| */ |
| T1 reverseTransform(T2 o); |
| |
| |
| final class Null<S1, S2> implements BidiTransformer<S1, S2>, Serializable { |
| @SuppressWarnings("rawtypes") |
| public static final BidiTransformer INSTANCE = new Null(); |
| @SuppressWarnings("unchecked") |
| public static <R1, R2> BidiTransformer<R1, R2> instance() { |
| return INSTANCE; |
| } |
| // ensure single instance |
| private Null() { |
| super(); |
| } |
| // simply return the object, unchanged |
| @SuppressWarnings("unchecked") |
| public S2 transform(S1 o) { |
| return (S2) o; |
| } |
| // simply return the object, unchanged |
| @SuppressWarnings("unchecked") |
| public S1 reverseTransform(S2 o) { |
| return (S1) o; |
| } |
| @Override |
| public String toString() { |
| return "BidiTransformer.Null"; //$NON-NLS-1$ |
| } |
| private static final long serialVersionUID = 1L; |
| private Object readResolve() { |
| // replace this object with the singleton |
| return INSTANCE; |
| } |
| } |
| |
| final class Disabled<S1, S2> implements BidiTransformer<S1, S2>, Serializable { |
| @SuppressWarnings("rawtypes") |
| public static final BidiTransformer INSTANCE = new Disabled(); |
| @SuppressWarnings("unchecked") |
| public static <R1, R2> BidiTransformer<R1, R2> instance() { |
| return INSTANCE; |
| } |
| // ensure single instance |
| private Disabled() { |
| super(); |
| } |
| // throw an exception |
| public S2 transform(S1 o) { |
| throw new UnsupportedOperationException(); |
| } |
| // throw an exception |
| public S1 reverseTransform(S2 o) { |
| throw new UnsupportedOperationException(); |
| } |
| @Override |
| public String toString() { |
| return "BidiTransformer.Disabled"; //$NON-NLS-1$ |
| } |
| private static final long serialVersionUID = 1L; |
| private Object readResolve() { |
| // replace this object with the singleton |
| return INSTANCE; |
| } |
| } |
| |
| } |