| /******************************************************************************* |
| * Copyright (c) 2013 Oracle. All rights reserved. |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Public License 2.0, which accompanies this distribution |
| * and is available at https://www.eclipse.org/legal/epl-2.0/. |
| * |
| * Contributors: |
| * Oracle - initial API and implementation |
| ******************************************************************************/ |
| package org.eclipse.jpt.common.utility.internal.transformer; |
| |
| import org.eclipse.jpt.common.utility.internal.ObjectTools; |
| import org.eclipse.jpt.common.utility.internal.iterable.IterableTools; |
| import org.eclipse.jpt.common.utility.transformer.Transformer; |
| |
| /** |
| * A chain of transformers. Pass the chain's input to the first |
| * transformer; take that transformer's output and pass it to the following |
| * transformer in the chain; etc. The output from the final transformer is |
| * returned as the chain's output. |
| * <p> |
| * <strong>NB:</strong> The transformer's generic types are for convenience only |
| * and cannot be enforced on the transformers in the chain. |
| * |
| * @param <I> input: the type of the object passed to the transformer |
| * @param <O> output: the type of the object returned by the transformer |
| */ |
| public class TransformerChain<I, O> |
| implements Transformer<I, O> |
| { |
| private final Iterable<Transformer<?, ?>> transformers; |
| |
| public TransformerChain(Iterable<Transformer<?, ?>> transformers) { |
| super(); |
| if (IterableTools.isOrContainsNull(transformers)) { |
| throw new NullPointerException(); |
| } |
| this.transformers = transformers; |
| } |
| |
| @SuppressWarnings({ "unchecked", "rawtypes" }) |
| public O transform(I input) { |
| Object result = input; |
| for (Transformer transformer : this.transformers) { |
| result = transformer.transform(result); |
| } |
| return (O) result; |
| } |
| |
| @Override |
| public String toString() { |
| return ObjectTools.toString(this, this.transformers); |
| } |
| } |