    001// Licensed under the Apache License, Version 2.0 (the "License");
    002// you may not use this file except in compliance with the License.
    003// You may obtain a copy of the License at
    004//
    005// http://www.apache.org/licenses/LICENSE-2.0
    006//
    007// Unless required by applicable law or agreed to in writing, software
    008// distributed under the License is distributed on an "AS IS" BASIS,
    009// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    010// See the License for the specific language governing permissions and
    011// limitations under the License.
    012
    013package org.apache.tapestry5.func;
    014
    015/**
    016 * Interface for operation {@link Flow#map(Mapper)} to define how Flow elements are mapped from one type
    017 * to another (or otherwise transformed).
    018 *
    019 * This changed in 5.3 from an abstract base class to an interface.
    020 *
    021 * @since 5.2.0
    022 * @param <S>
    023 *            type of source flow
    024 * @param <T>
    025 *            type of target (output) flow
    026 */
    027public interface Mapper<S, T>
    028{
    029    /**
    030     * Implemented in subclasses to map an element from the source flow to an element of the target
    031     * flow.
    032     */
    033    T map(S element);
    034}