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Tomcat example source code file (BodyContent.java)

This example Tomcat source code file (BodyContent.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Tomcat tags/keywords

bodycontent, bodycontent, error, http, illegal, io, ioexception, ioexception, jspwriter, jspwriter, reader, reader, servlet, string

The Tomcat BodyContent.java source code

/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements.  See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 javax.servlet.jsp.tagext;

import java.io.Reader;
import java.io.Writer;
import java.io.IOException;
import javax.servlet.jsp.*;

/**
 * An encapsulation of the evaluation of the body of an action so it is
 * available to a tag handler.  BodyContent is a subclass of JspWriter.
 *
 * <p>
 * Note that the content of BodyContent is the result of evaluation, so
 * it will not contain actions and the like, but the result of their
 * invocation.
 * 
 * <p>
 * BodyContent has methods to convert its contents into
 * a String, to read its contents, and to clear the contents.
 *
 * <p>
 * The buffer size of a BodyContent object is unbounded.  A
 * BodyContent object cannot be in autoFlush mode.  It is not possible to
 * invoke flush on a BodyContent object, as there is no backing stream.
 *
 * <p>
 * Instances of BodyContent are created by invoking the pushBody and
 * popBody methods of the PageContext class.  A BodyContent is enclosed
 * within another JspWriter (maybe another BodyContent object) following
 * the structure of their associated actions.
 *
 * <p>
 * A BodyContent is made available to a BodyTag through a setBodyContent()
 * call.  The tag handler can use the object until after the call to
 * doEndTag().
 */

public abstract class BodyContent extends JspWriter {
    
    /**
     * Protected constructor.
     *
     * Unbounded buffer, no autoflushing.
     *
     * @param e the enclosing JspWriter
     */

    protected BodyContent(JspWriter e) {
	super(UNBOUNDED_BUFFER , false);
	this.enclosingWriter = e;
    }

    /**
     * Redefined flush() so it is not legal.
     *
     * <p>
     * It is not valid to flush a BodyContent because there is no backing
     * stream behind it.
     *
     * @throws IOException always thrown
     */

    public void flush() throws IOException {
	throw new IOException("Illegal to flush within a custom tag");
    }

    /**
     * Clear the body without throwing any exceptions.
     */
    
    public void clearBody() {
	try {
	    this.clear();
	} catch (IOException ex) {
	    // TODO -- clean this one up.
	    throw new Error("internal error!;");
	}
    }

    /**
     * Return the value of this BodyContent as a Reader.
     *
     * @return the value of this BodyContent as a Reader
     */
    public abstract Reader getReader();


    /**
     * Return the value of the BodyContent as a String.
     *
     * @return the value of the BodyContent as a String
     */
    public abstract String getString();
	

    /**
     * Write the contents of this BodyContent into a Writer.
     * Subclasses may optimize common invocation patterns.
     *
     * @param out The writer into which to place the contents of
     *     this body evaluation
     * @throws IOException if an I/O error occurred while writing the
     *     contents of this BodyContent to the given Writer
     */

    public abstract void writeOut(Writer out) throws IOException;


    /**
     * Get the enclosing JspWriter.
     *
     * @return the enclosing JspWriter passed at construction time
     */

    public JspWriter getEnclosingWriter() {
	return enclosingWriter;
    }


    // private fields

    private JspWriter enclosingWriter;
 }

Other Tomcat examples (source code examples)

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