framework/src/net/sf/tapestry/wml/WMLWriter.java

/*
 *  ====================================================================
 *  The Apache Software License, Version 1.1
 *
 *  Copyright (c) 2002 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 Tapestry" 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 Tapestry", 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/>.
 */
package net.sf.tapestry.wml;

import java.io.OutputStream;

import net.sf.tapestry.AbstractMarkupWriter;
import net.sf.tapestry.IMarkupWriter;

/**
 *  This class is used to create WML output.
 *
 *  <p>The <code>WMLResponseWriter</code> handles the necessary escaping 
 *  of invalid characters.
 *  Specifically, the '$', '&lt;', '&gt;' and '&amp;' characters are properly
 *  converted to their WML entities by the <code>print()</code> methods.
 *  Similar measures are taken by the {@link #attribute(String, String)} method.
 *  Other invalid characters are converted to their numeric entity equivalent.
 *
 *  <p>This class makes it easy to generate trivial and non-trivial WML pages.
 *  It is also useful to generate WML snippets. It's ability to do simple
 *  formatting is very useful. A JSP may create an instance of the class
 *  and use it as an alternative to the simple-minded <b>&lt;%= ... %&gt;</b>
 *  construct, espcially because it can handle null more cleanly.
 *
 *  @version $Id$
 *  @author David Solis
 *  @since 0.2.9
 * 
 **/

public class WMLWriter extends AbstractMarkupWriter
{

    private static final String[] entities = new String[64];
    private static final boolean[] safe = new boolean[128];
    private static final String SAFE_CHARACTERS =
        "01234567890"
            + "abcdefghijklmnopqrstuvwxyz"
            + "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
            + "\t\n\r !\"#%'()*+,-./:;=?@[\\]^_`{|}~";

    static {
        entities['"'] = "&quot;";
        entities['<'] = "&lt;";
        entities['>'] = "&gt;";
        entities['&'] = "&amp;";
        entities['$'] = "$$";

        int length = SAFE_CHARACTERS.length();
        for (int i = 0; i < length; i++)
            safe[SAFE_CHARACTERS.charAt(i)] = true;
    }

    /**
     *  Creates a response writer for content type "text/vnd.wap.wml".
     * 
     **/

    public WMLWriter(OutputStream stream)
    {
        this("text/vnd.wap.wml", stream);
    }

    public WMLWriter(String contentType, OutputStream stream)
    {
        super(safe, entities, contentType, stream);
    }

    protected WMLWriter(String contentType)
    {
        super(safe, entities, contentType);
    }

    public IMarkupWriter getNestedWriter()
    {
        return new NestedWMLWriter(this);
    }

    public String getContentType()
    {
        return "";
    }
}