setdateheadertag.java

来自「jakarta-taglibs」· Java 代码 · 共 92 行

/*
 * 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>setDateHeader</b>, used to add a header for the HTTP Response.
 * <p>
 * The header value is set to the content of the body of the <b>setDateHeader</b> tag.
 * <p>
 * JSP Tag Lib Descriptor
 * <p><pre>
 * &lt;name&gt;setDateHeader&lt;/name&gt;
 * &lt;tagclass&gt;org.apache.taglibs.response.SetDateHeaderTag&lt;/tagclass&gt;
 * &lt;bodycontent&gt;JSP&lt;/bodycontent&gt;
 * &lt;info&gt;Set a single HTTP date header.&lt;/info&gt;
 * </pre>
 *
 * @author Glenn Nielsen
 */

public class SetDateHeaderTag extends BodyTagSupport
{
    private String name = 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 setDateHeader tag to obtain the header value.
     *
     * @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();

	long value = 0;
	try {
	    value = Long.valueOf(s).longValue();
	} catch(NumberFormatException e) {
	    throw new JspException("Response tag setDateHeader: " +
		e.getMessage());
	}

	((HttpServletResponse)pageContext.getResponse()).setDateHeader(name,value);
        return SKIP_BODY;
    }

    /**   
     * Required attribute, name of the header.
     *
     * @param String name
     */
    public final void setName(String nam)
    {
	name = nam;
    }

}