001// Copyright 2011 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007// http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.ioc.internal;
016
017import org.apache.tapestry5.commons.services.TypeCoercer;
018
019/**
020 * A simplified version of {@link TypeCoercer} used to defer the instantiation of the actual TypeCoercer
021 * service until necessary.
022 * 
023 * @since 5.3
024 */
025public interface TypeCoercerProxy
026{
027    /**
028     * Returns input cast to targetType if input is an instance of target type, otherwise delegates
029     * to {@link TypeCoercer#coerce(Object, Class)}.
030     * 
031     * @param <S>
032     * @param <T>
033     * @param input
034     *            value to be coerced
035     * @param targetType
036     *            desired type of value
037     * @return the value, coerced
038     * @throws RuntimeException
039     *             if the input can not be coerced
040     */
041    <S, T> T coerce(S input, Class<T> targetType);
042
043}