/*
 * Copyright 1999,2004 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.taglibs.response;

import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;

/**
 * JSP Tag <b>encodeUrl</b>, used to encode a URL with the session id
 * if necessary.
 * <p>
 * The <b>encodeUrl</b> tag gets the URL to encode from the body of the tag,
 * and outputs it after encoding it.
 * <p>
 * JSP Tag Lib Descriptor
 * <p><pre>
 * &lt;name&gt;encodeUrl&lt;/name&gt;
 * &lt;tagclass&gt;org.apache.taglibs.response.EncodeURLTag&lt;/tagclass&gt;
 * &lt;bodycontent&gt;JSP&lt;/bodycontent&gt;
 * &lt;info&gt;Encode a URL with the JSESSIONID if necessary.&lt;/info&gt;
 * </pre>
 *
 * @author Glenn Nielsen
 */

public class EncodeURLTag extends BodyTagSupport
{
    private String encoded_url = null;

    /**
     * Method called at start of tag, just returns EVAL_BODY_TAG
     *
     * @return EVAL_BODY_TAG
     */
    public final int doStartTag() throws JspException
    {
	return EVAL_BODY_TAG;
    }

    /**
     * Read the body of the encodeUrl tag to obtain the URL to encode,
     * then encode the URL and output it back to the page.
     *
     * @return SKIP_BODY
     */
    public final int doAfterBody() throws JspException
    {
        // Use the body of the tag as header value
        BodyContent body = getBodyContent();
        String s = body.getString().trim();
        // Clear the body since we only used it as input for the header
        // value
        body.clearBody();

	encoded_url =
	    ((HttpServletResponse)pageContext.getResponse()).encodeURL(s);

        return SKIP_BODY;
    }

    /**     
     * Output the result of the calculation
     *      
     * @return EVAL_PAGE
     */     
    public final int doEndTag() throws JspException
    {         
	try {       
	    pageContext.getOut().write(encoded_url);
	} catch(Exception e) {
	    throw new JspException("IO Error: " + e.getMessage());
	}
	return EVAL_PAGE;
    }

}