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.runtime;
014
015import org.apache.tapestry5.MarkupWriter;
016import org.apache.tapestry5.annotations.OnEvent;
017
018/**
019 * Interface that defines the lifecycle of a component, within a page, allowing for callbacks into the component for
020 * many different events. This interface is part of the public API for Tapestry, but is <em>not</em> expected to be
021 * directly implemented by component classes; it should only be implemented as part of the component class
022 * transformation process.
023 *
024 * Most of the methods are related to render phases; see the corresponding annotations and component rendering
025 * documentation to see how they relate to each other.
026 *
027 * Starting in 5.3 this interface no longer implements {@link PageLifecycleListener}. Normally, this would be an incompatible
028 * change, but Component is not supposed to be directly implemented by user code.
029 */
030public interface Component extends ComponentResourcesAware
031{
032
033    /**
034     * Lifecycle method invoked at the end of the {@link org.apache.tapestry5.annotations.CleanupRender} render phase.
035     * There is no annotation for this method, it is part of CleanupRender, but is always invoked. Its specific use is
036     * to allow components to clean up cached parameter values.
037     */
038    void postRenderCleanup();
039
040    /**
041     * Invoked before rendering a component (or its template).
042     */
043    void setupRender(MarkupWriter writer, Event event);
044
045    /**
046     * Invoked to allow a component to render its tag (start tag and attributes).
047     */
048    void beginRender(MarkupWriter writer, Event event);
049
050    /**
051     * This phase is only invoked for components with templates.
052     */
053    void beforeRenderTemplate(MarkupWriter writer, Event event);
054
055    /**
056     * Invoked after rendering the template for a component (only for components with a template).
057     */
058    void afterRenderTemplate(MarkupWriter writer, Event event);
059
060    /**
061     * Invoked just before rendering the body of component.
062     */
063    void beforeRenderBody(MarkupWriter writer, Event event);
064
065    /**
066     * Invoked just after rendering the body of the component.
067     */
068    void afterRenderBody(MarkupWriter writer, Event event);
069
070    /**
071     * Generally used to write the close tag matching any open tag written by {@link
072     * #beginRender(org.apache.tapestry5.MarkupWriter, Event)}.
073     */
074    void afterRender(MarkupWriter writer, Event event);
075
076    /**
077     * Generally used to perform final cleanup of the component after rendering.
078     */
079    void cleanupRender(MarkupWriter writer, Event event);
080
081    /**
082     * Invoked to handle a component event. Methods with the {@link OnEvent} annotation (or the matching naming
083     * convention) will be invoked until one returns a non-null value.
084     *
085     * @param event
086     * @return true if any handler was found (and invoked), false otherwise
087     * @throws RuntimeException wrapping any checked exceptions that are thrown by individual event handler methods
088     */
089    boolean dispatchComponentEvent(ComponentEvent event);
090}