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;
014
015import java.io.Serializable;
016
017/**
018 * An action that is associated with a component. This is used in several areas of Tapestry and is primarily an attempt
019 * to externalize state for a component so that it can be recorded outside the object.
020 *
021 * ComponentActions should be immutable. They are often created during one request and associated with a particular
022 * component instance. They are then used in a later request (with an equivalent component instance).
023 *
024 * ComponentActions are serializable (they are often serialized into Base64 strings for storage on the client).
025 */
026public interface ComponentAction<T> extends Serializable
027{
028    /**
029     * Passed a component instance, the action should operate upon the instance.
030     */
031    void execute(T component);
032}