BufferAppendTag.java :  » Development » ivatamasks » com » ivata » mask » web » tag » util » Java Open Source

/*
 * Copyright (c) 2001 - 2005 ivata limited.
 * All rights reserved.
 * -----------------------------------------------------------------------------
 * ivata masks may be redistributed under the GNU General Public
 * License as published by the Free Software Foundation;
 * version 2 of the License.
 *
 * These programs are free software; you can redistribute them and/or
 * modify them under the terms of the GNU General Public License
 * as published by the Free Software Foundation; version 2 of the License.
 *
 * These programs are distributed in the hope that they will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * See the GNU General Public License in the file LICENSE.txt for more
 * details.
 *
 * If you would like a copy of the GNU General Public License write to
 *
 * Free Software Foundation, Inc.
 * 59 Temple Place - Suite 330
 * Boston, MA 02111-1307, USA.
 *
 *
 * To arrange commercial support and licensing, contact ivata at
 *                  http://www.ivata.com/contact.jsp
 * -----------------------------------------------------------------------------
 * $Log: BufferAppendTag.java,v $
 * Revision 1.5  2005/10/11 18:54:06  colinmacleod
 * Fixed some checkstyle and javadoc issues.
 *
 * Revision 1.4  2005/10/03 10:17:25  colinmacleod
 * Fixed some style and javadoc issues.
 *
 * Revision 1.3  2005/10/02 14:06:34  colinmacleod
 * Added/improved log4j logging.
 *
 * Revision 1.2  2005/09/14 13:23:58  colinmacleod
 * Added serialVersionUID.
 *
 * Revision 1.1  2005/04/26 15:05:32  colinmacleod
 * Added string buffer append tag.
 *
 * -----------------------------------------------------------------------------
 */
package com.ivata.mask.web.tag.util;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.BodyTagSupport;

import org.apache.log4j.Logger;


/**
 * Appends the JSP contents to a <code>StringBuffer</code>.
 *
 * @since ivata masks 0.6 (2005-04-26)
 * @author Colin MacLeod
 * <a href='mailto:colin.macleod@ivata.com'>colin.macleod@ivata.com</a>
 * @version $Revision: 1.5 $
 */
public class BufferAppendTag extends BodyTagSupport {
    /**
     * Serialization version (for <code>Serializable</code> interface).
     */
    private static final long serialVersionUID = 1L;

    /**
     * Logger for this class.
     */
    private static final Logger logger = Logger
            .getLogger(BufferAppendTag.class);

    /**
     * <copyDoc>Refer to {@link #getBufferName}.</copyDoc>
     */
    private String bufferName = null;
    /**
     * Stores the value of the current page.
     */
    private String value = null;

    /**
     * <p>This method is called after the JSP engine processes the body
     * content of the tag.</p>
     * @exception JspException encapsulates any exception when calling
     * {@link #writeTagBodyContent writeTagBodyContent}.
     * @return <code>SKIP_BODY</code> since we only ever want to evaluate
     * this tag once.
     * @see #writeTagBodyContent
     * )
     *
     */
    public int doAfterBody() throws JspException {
        if (logger.isDebugEnabled()) {
            logger.debug("doAfterBody() - start");
        }

        if (getBodyContent() != null) {
            value = getBodyContent().getString();
        } else {
            value = null;
        }

        if (logger.isDebugEnabled()) {
            logger.debug("doAfterBody() - end - return value = " + SKIP_BODY);
        }
        return SKIP_BODY;
    }

    /**
     * <p>This method is called after the JSP engine finished processing
     * the tag.</p>
     *
     * @exception JspException encapsulates any exception when calling
     * <code>out.println</code>
     * @return <code>EVAL_PAGE</code> since we always want to evaluate
     * the page after this tag.
     */
    public int doEndTag() throws JspException {
        if (logger.isDebugEnabled()) {
            logger.debug("doEndTag() - start");
        }

        StringBuffer buffer = (StringBuffer) pageContext
            .findAttribute(bufferName);
        if (buffer == null) {
            throw new JspException("Cannot find buffer called '"
                    + bufferName
                    + "' at any scope.");
        }

        if (value != null) {
            buffer.append(value);
        }

        if (logger.isDebugEnabled()) {
            logger.debug("doEndTag() - end - return value = " + EVAL_PAGE);
        }
        return EVAL_PAGE;
    }

    /**
     * <p>
     * Use this attribute to specify a <code>java.lang.StringBuffer</code>
     * instance in the current page context.
     * </p>
     *
     * @return the current value of mapName.
     */
    public final String getBufferName() {
        if (logger.isDebugEnabled()) {
            logger.debug("getBufferName() - start");
        }

        if (logger.isDebugEnabled()) {
            logger
                    .debug("getBufferName() - end - return value = "
                            + bufferName);
        }
        return bufferName;
    }
    /**
     * <copyDoc>Refer to {@link #getBufferName}.</copyDoc>
     * @param bufferNameParam
     * <copyDoc>Refer to {@link #getBufferName}.</copyDoc>
     */
    public void setBufferName(final String bufferNameParam) {
        if (logger.isDebugEnabled()) {
            logger.debug("Setting bufferName. Before '" + bufferName
                    + "', after '" + bufferNameParam + "'");
        }
        bufferName = bufferNameParam;

        if (logger.isDebugEnabled()) {
            logger.debug("setBufferName(String) - end");
        }
    }
}