    001// Copyright 2010, 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.func;
    016
    017/**
    018 * Interface for operation {@link Flow#map(Mapper)} to define how Flow elements are mapped from one type
    019 * to another (or otherwise transformed).
    020 * <p>
    021 * This changed in 5.3 from an abstract base class to an interface.
    022 *
    023 * @since 5.2.0
    024 * @param <S>
    025 *            type of source flow
    026 * @param <T>
    027 *            type of target (output) flow
    028 */
    029public interface Mapper<S, T>
    030{
    031    /**
    032     * Implemented in subclasses to map an element from the source flow to an element of the target
    033     * flow.
    034     */
    035    T map(S element);
    036}