    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.services;
    014
    015import org.apache.tapestry5.ioc.annotations.UsesMappedConfiguration;
    016
    017/**
    018 * Service that allows replacing one component, page or mixin class by another without changing the sources.
    019 * This service shouldn't be used directly: it's not an internal service just because it receives
    020 * contributions.
    021 *
    022 * Contributions to it are mapped: the key is the component, page or mixin class to be
    023 * replaced, the value is the replacement.
    024 *
    025 * @since 5.4
    026 * @see org.apache.tapestry5.services.ComponentClassResolver
    027 */
    028@UsesMappedConfiguration(key = Class.class, value = Class.class)
    029public interface ComponentOverride
    030{
    031
    032    /**
    033     * Returns true if the service configuration is non-empty.
    034     *
    035     */
    036   boolean hasReplacements();
    037
    038    /**
    039     * Returns the replacement for a class given its name.
    040     * @param className the fully qualified class name.
    041     * @return a {@link Class} or null.
    042     */
    043    Class getReplacement(String className);
    044
    045}