- /*
- * 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.collections;
-
- /**
- * 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.
- *
- * @since Commons Collections 1.0
- * @version $Revision: 1.10 $ $Date: 2004/04/14 20:08:57 $
- *
- * @author James Strachan
- * @author Stephen Colebourne
- */
- public interface Transformer {
-
- /**
- * 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 Object transform(Object input);
-
- }