BodyTag.java
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上传日期:2013-06-23
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- /*
- * The Apache Software License, Version 1.1
- *
- * Copyright (c) 1999 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 acknowlegement:
- * "This product includes software developed by the
- * Apache Software Foundation (http://www.apache.org/)."
- * Alternately, this acknowlegement may appear in the software itself,
- * if and wherever such third-party acknowlegements normally appear.
- *
- * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
- * Foundation" 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"
- * nor may "Apache" appear in their names without prior written
- * permission of the Apache Group.
- *
- * 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 javax.servlet.jsp.tagext;
- import javax.servlet.jsp.*;
- /**
- * The BodyTag interface extends Tag by defining additional methods that let
- * a Tag handler access its body.
- * <p>
- * The interface provides two new methods: one is to be invoked with the BodyContent
- * for the evaluation of the body, the other is to be reevaluated after every body
- * evaluation.
- * <p>
- * Without repeating the portions described in Tag.java, a typical invocation sequence is:
- *
- * <pre>
- * <code>
- *
- * -- we are picking up after all the setters have been done
- * t.doStartTag();
- * out = pageContext.pushBody();
- * -- prepare for body
- * t.setBodyContent(out);
- * -- preamble
- * t.doBodyInit();
- * -- BODY evaluation into out
- * t.doAfterBody();
- * -- while doAfterBody returns EVAL_BODY_TAG we iterate
- * -- BODY evaluation into out
- * t.doAfterBody()
- * -- done
- * t.doEndTag()
- *
- * </code>
- * </pre>
- */
- public interface BodyTag extends Tag {
- /**
- * Request the creation of new BodyContent on which to evaluate the
- * body of this tag.
- * Returned from doStartTag and doAfterBody.
- * This is an illegal return value for doStartTag when the class does not
- * implement BodyTag, since BodyTag is needed to manipulate the new Writer.
- */
-
- public final static int EVAL_BODY_TAG = 2;
- /**
- * Setter method for the bodyContent property.
- * <p>
- * This method will not be invoked if there is no body evaluation.
- *
- * @param b the BodyContent
- * @seealso #doInitBody
- * @seealso #doAfterBody
- */
- void setBodyContent(BodyContent b);
- /**
- * Prepare for evaluation of the body.
- * <p>
- * The method will be invoked once per action invocation by the page implementation
- * after a new BodyContent has been obtained and set on the tag handler
- * via the setBodyContent() method and before the evaluation
- * of the tag's body into that BodyContent.
- * <p>
- * This method will not be invoked if there is no body evaluation.
- *
- * @seealso #doAfterBody
- */
- void doInitBody() throws JspException;
- /**
- * Actions after some body has been evaluated.
- * <p>
- * 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
- */
- int doAfterBody() throws JspException;
- }