    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
    015package org.apache.tapestry5.corelib.components;
    016
    017import org.apache.tapestry5.BindingConstants;
    018import org.apache.tapestry5.ComponentResources;
    019import org.apache.tapestry5.MarkupWriter;
    020import org.apache.tapestry5.annotations.Parameter;
    021import org.apache.tapestry5.ioc.annotations.Inject;
    022import 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 */
    031public 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}