001    // Copyright 2006, 2007, 2009 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.annotations;
016    
017    import java.lang.annotation.Documented;
018    import java.lang.annotation.ElementType;
019    import java.lang.annotation.Retention;
020    import static java.lang.annotation.RetentionPolicy.RUNTIME;
021    import java.lang.annotation.Target;
022    
023    import static org.apache.tapestry5.ioc.annotations.AnnotationUseContext.*;
024    import org.apache.tapestry5.ioc.annotations.UseWith;
025    
026    /**
027     * Marker annotation for methods that should be executed at the start of rendering the component. This usually includes
028     * rendering of the component's start tag.
029     * <p/>
030     * Such methods may optionally take a {@link org.apache.tapestry5.MarkupWriter} parameter, and may return void or
031     * boolean. Returning true or void will allow the component to advance into the render template / render body phase. If
032     * a body is present, the {@link org.apache.tapestry5.annotations.BeforeRenderBody} phase will execute. If a component
033     * has a template, the {@link BeforeRenderTemplate} phase will execute (and the render body will only occur if the
034     * template directs so).
035     * <p/>
036     * Either way, the {@link org.apache.tapestry5.annotations.AfterRender} phase will execute after the template and/or
037     * body have rendered. A component with a body but without a template will still see the {@link
038     * org.apache.tapestry5.annotations.BeforeRenderBody} phase execute.
039     * <p/>
040     * Returning false will skip rendering of the template and/or body, and jump directly to the {@link AfterRender} phase.
041     */
042    @Target(ElementType.METHOD)
043    @Retention(RUNTIME)
044    @Documented
045    @UseWith({COMPONENT,MIXIN,PAGE})
046    public @interface BeginRender
047    {
048    
049    }