    001    // Copyright 2009, 2010, 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.corelib.components;
    016
    017    import org.apache.tapestry5.BindingConstants;
    018    import org.apache.tapestry5.ComponentResources;
    019    import org.apache.tapestry5.MarkupWriter;
    020    import org.apache.tapestry5.annotations.Parameter;
    021    import org.apache.tapestry5.ioc.annotations.Inject;
    022    import org.apache.tapestry5.services.javascript.JavaScriptSupport;
    023
    024    /**
    025     * Triggers an arbitrary event during rendering. This is often useful to add JavaScript
    026     * to a page or a component (via calls to the {@link JavaScriptSupport} environmental).
    027     *
    028     * @since 5.2.0
    029     * @tapestrydoc
    030     */
    031    public class Trigger
    032    {
    033        @Parameter(defaultPrefix = BindingConstants.LITERAL)
    034        private String event;
    035
    036        @Inject
    037        private ComponentResources resources;
    038
    039        String defaultEvent()
    040        {
    041            return this.resources.getId();
    042        }
    043
    044        boolean beginRender(MarkupWriter writer)
    045        {
    046            this.resources.triggerEvent(this.event, new Object[]
    047            { writer }, null);
    048            return false;
    049        }
    050
    051    }