001    // Copyright 2006, 2009, 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    
015    package org.apache.tapestry5.runtime;
016    
017    import org.apache.tapestry5.MarkupWriter;
018    import org.apache.tapestry5.annotations.OnEvent;
019    
020    /**
021     * Interface that defines the lifecycle of a component, within a page, allowing for callbacks into the component for
022     * many different events. This interface is part of the public API for Tapestry, but is <em>not</em> expected to be
023     * directly implemented by component classes; it should only be implemented as part of the component class
024     * transformation process.
025     * <p/>
026     * Most of the methods are related to render phases; see the corresponding annotations and component rendering
027     * documentation to see how they relate to each other.
028     * <p/>
029     * Starting in 5.3 this interface no longer implements {@link PageLifecycleListener}. Normally, this would be an incompatible
030     * change, but Component is not supposed to be directly implemented by user code.
031     */
032    public interface Component extends ComponentResourcesAware
033    {
034    
035        /**
036         * Lifecycle method invoked at the end of the {@link org.apache.tapestry5.annotations.CleanupRender} render phase.
037         * There is no annotation for this method, it is part of CleanupRender, but is always invoked. Its specific use is
038         * to allow components to clean up cached parameter values.
039         */
040        void postRenderCleanup();
041    
042        /**
043         * Invoked before rendering a component (or its template).
044         */
045        void setupRender(MarkupWriter writer, Event event);
046    
047        /**
048         * Invoked to allow a component to render its tag (start tag and attributes).
049         */
050        void beginRender(MarkupWriter writer, Event event);
051    
052        /**
053         * This phase is only invoked for components with templates.
054         */
055        void beforeRenderTemplate(MarkupWriter writer, Event event);
056    
057        /**
058         * Invoked after rendering the template for a component (only for components with a template).
059         */
060        void afterRenderTemplate(MarkupWriter writer, Event event);
061    
062        /**
063         * Invoked just before rendering the body of component.
064         */
065        void beforeRenderBody(MarkupWriter writer, Event event);
066    
067        /**
068         * Invoked just after rendering the body of the component.
069         */
070        void afterRenderBody(MarkupWriter writer, Event event);
071    
072        /**
073         * Generally used to write the close tag matching any open tag written by {@link
074         * #beginRender(org.apache.tapestry5.MarkupWriter, Event)}.
075         */
076        void afterRender(MarkupWriter writer, Event event);
077    
078        /**
079         * Generally used to perform final cleanup of the component after rendering.
080         */
081        void cleanupRender(MarkupWriter writer, Event event);
082    
083        /**
084         * Invoked to handle a component event. Methods with the {@link OnEvent} annotation (or the matching naming
085         * convention) will be invoked until one returns a non-null value.
086         *
087         * @param event
088         * @return true if any handler was found (and invoked), false otherwise
089         * @throws RuntimeException wrapping any checked exceptions that are thrown by individual event handler methods
090         */
091        boolean dispatchComponentEvent(ComponentEvent event);
092    }