src/java/org/apache/turbine/services/jsp/util/JspScreenPlaceholder.java

package org.apache.turbine.services.jsp.util;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001-2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache Turbine" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache Turbine", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.apache.turbine.modules.ScreenLoader;
import org.apache.turbine.services.template.TurbineTemplate;
import org.apache.turbine.util.RunData;

/**
 * Returns output of a Screen module. An instance of this is placed in the
 * request by the JspLayout. This allows template authors to
 * place the screen template within the layout.<br>
 * Here's how it's used in a JSP template:<br>
 * <code>
 * <%useBean id="screen_placeholder" class="JspScreenPlaceholder" scope="request"/%>
 * ...
 * <%= screen_placeholder %>
 *</code>
 *
 * @author <a href="john.mcnally@clearink.com">John D. McNally</a>
 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
 * @version $Id$
 */
public class JspScreenPlaceholder
{
    /** Logging */
    private static Log log = LogFactory.getLog(JspNavigation.class);

    /* The RunData object */
    private RunData data;

    /**
     * Constructor
     *
     * @param data A Rundata Object
     */
    public JspScreenPlaceholder(RunData data)
    {
        this.data = data;
    }

    /**
     * builds the output of the navigation template
     */
    public void exec()
    {
        String template = null;
        String module = null;
        try
        {
            template = data.getTemplateInfo().getScreenTemplate();
            module = TurbineTemplate.getScreenName(template);
            ScreenLoader.getInstance().exec(data, module);
        }
        catch (Exception e)
        {
            String message = "Error processing navigation template:" +
                    template + " using module: " + module;
            log.error(message, e);
            try
            {
                data.getOut().print("Error processing navigation template: "
                        + template + " using module: " + module);
            }
            catch (java.io.IOException ioe)
            {
            }
        }
    }
}