// 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);
}