Java tutorial
// GenericsNote: Converted. /* * Copyright 2001-2004 The Apache Software Foundation * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.commons.collections15; /** * Defines a functor interface implemented by classes that transform one * object into another. * <p/> * A <code>Transformer</code> converts the input object to the output object. * The input object should be left unchanged. * Transformers are typically used for type conversions, or extracting data * from an object. * <p/> * Standard implementations of common transformers are provided by * {@link TransformerUtils}. These include method invokation, returning a constant, * cloning and returning the string value. * * @author James Strachan * @author Matt Hall, John Watkinson, Stephen Colebourne * @version $Revision: 1.1 $ $Date: 2005/10/11 17:05:19 $ * @since Commons Collections 1.0 */ public interface Transformer<I, O> { /** * Transforms the input object (leaving it unchanged) into some output object. * * @param input the object to be transformed, should be left unchanged * @return a transformed object * @throws ClassCastException (runtime) if the input is the wrong class * @throws IllegalArgumentException (runtime) if the input is invalid * @throws FunctorException (runtime) if the transform cannot be completed */ public O transform(I input); }