bodytagsupport.java

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/*
 * The Apache Software License, Version 1.1
 *
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 * reserved.
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 *    any, must include the following acknowlegement:  
 *       "This product includes software developed by the 
 *        Apache Software Foundation (http://www.apache.org/)."
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package javax.servlet.jsp.tagext;

import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;

import javax.servlet.*;

import java.io.Writer;

import java.util.Hashtable;

/**
 * Actions in a Tag Library are defined through subclasses of Tag.
 */

public class BodyTagSupport extends TagSupport implements BodyTag {

    /**
     * Default constructor, all subclasses are required to only define
     * a public constructor with the same signature, and to call the
     * superclass constructor.
     *
     * This constructor is called by the code generated by the JSP
     * translator.
     *
     */

    public BodyTagSupport() {
	super();
    }

    /**
     * Process the start tag for this instance.
     *
     * The doStartTag() method assumes that all setter methods have been
     * invoked before.
     *
     * When this method is invoked, the body has not yet been invoked.
     *
     * @returns EVAL_BODY_TAG if the tag wants to process body, SKIP_BODY if it
     * does ont want to process it.
     */
 
    public int doStartTag() throws JspException {
        return EVAL_BODY_TAG;
    }


    /**
     * Process the end tag. This method will be called on all Tag objects.
     *
     * All instance state associated with this instance must be reset.
     * The release() method should be called after this invocation.
     */

    public int doEndTag() throws JspException {
	return super.doEndTag();
    }


    // Actions related to body evaluation

    /**
     * Prepare for evaluation of the body
     * It will be invoked at most once per action invocation.
     * Will not be invoked if there is no body evaluation.
     *
     * Frequently it is not redefined by Tag author.
     *
     * @param b the BodyContent
     * @seealso #doAfterBody
     */

    public void setBodyContent(BodyContent b) {
	this.bodyContent = b;
    }

    /**
     * Prepare for evaluation of the body
     * It will be invoked at most once per action invocation.
     * Will not be invoked if there is no body evaluation.
     *
     * Frequently it is not redefined by Tag author.
     *
     * @seealso #doAfterBody
     */

    public void doInitBody() throws JspException {
    }

    /**
     * Actions after some body has been evaluated.
     *
     * Not invoked in empty tags or in tags returning SKIP_BODY in doStartTag()
     * This method is invoked after every body evaluation.
     * The pair "BODY -- doAfterBody()" is invoked initially if doStartTag()
     * returned EVAL_BODY_TAG, and it is repeated as long
     * as the doAfterBody() evaluation returns EVAL_BODY_TAG
     * <p>
     * The method re-invocations may be lead to different actions because
     * there might have been some changes to shared state, or because
     * of external computation.
     *
     * @returns whether additional evaluations of the body are desired
     * @seealso #doInitBody
     */

    public int doAfterBody() throws JspException {
 	return SKIP_BODY;
    }

    /**
     * reset the state of the Tag
     */

    public void release() {
	bodyContent = null;

	super.release();
    }

    /**
     * Get current bodyContent
     */
    
    public BodyContent getBodyContent() {
	return bodyContent;
    }


    /**
     * Get surrounding out
     */

    public JspWriter getPreviousOut() {
	return bodyContent.getEnclosingWriter();
    }

    // protected fields

    protected BodyContent   bodyContent;
}