1   /*
    2   * Licensed to the Apache Software Foundation (ASF) under one or more
    3   * contributor license agreements.  See the NOTICE file distributed with
    4   * this work for additional information regarding copyright ownership.
    5   * The ASF licenses this file to You under the Apache License, Version 2.0
    6   * (the "License"); you may not use this file except in compliance with
    7   * the License.  You may obtain a copy of the License at
    8   *
    9   *     http://www.apache.org/licenses/LICENSE-2.0
   10   *
   11   * Unless required by applicable law or agreed to in writing, software
   12   * distributed under the License is distributed on an "AS IS" BASIS,
   13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   14   * See the License for the specific language governing permissions and
   15   * limitations under the License.
   16   */
   17   package javax.servlet.jsp.tagext;
   18   
   19   import javax.servlet.jsp.JspException;
   20   import javax.servlet.jsp.JspWriter;
   21   
   22   /**
   23    * A base class for defining tag handlers implementing BodyTag.
   24    *
   25    * <p>
   26    * The BodyTagSupport class implements the BodyTag interface and adds
   27    * additional convenience methods including getter methods for the
   28    * bodyContent property and methods to get at the previous out JspWriter.
   29    *
   30    * <p>
   31    * Many tag handlers will extend BodyTagSupport and only redefine a
   32    * few methods.
   33    */
   34   
   35   public class BodyTagSupport extends TagSupport implements BodyTag {
   36   
   37       /**
   38        * Default constructor, all subclasses are required to only define
   39        * a public constructor with the same signature, and to call the
   40        * superclass constructor.
   41        *
   42        * This constructor is called by the code generated by the JSP
   43        * translator.
   44        */
   45   
   46       public BodyTagSupport() {
   47   	super();
   48       }
   49   
   50       /**
   51        * Default processing of the start tag returning EVAL_BODY_BUFFERED.
   52        *
   53        * @return EVAL_BODY_BUFFERED
   54        * @throws JspException if an error occurred while processing this tag
   55        * @see BodyTag#doStartTag
   56        */
   57    
   58       public int doStartTag() throws JspException {
   59           return EVAL_BODY_BUFFERED;
   60       }
   61   
   62   
   63       /**
   64        * Default processing of the end tag returning EVAL_PAGE.
   65        *
   66        * @return EVAL_PAGE
   67        * @throws JspException if an error occurred while processing this tag
   68        * @see Tag#doEndTag
   69        */
   70   
   71       public int doEndTag() throws JspException {
   72   	return super.doEndTag();
   73       }
   74   
   75   
   76       // Actions related to body evaluation
   77   
   78       /**
   79        * Prepare for evaluation of the body: stash the bodyContent away.
   80        *
   81        * @param b the BodyContent
   82        * @see #doAfterBody
   83        * @see #doInitBody()
   84        * @see BodyTag#setBodyContent
   85        */
   86   
   87       public void setBodyContent(BodyContent b) {
   88   	this.bodyContent = b;
   89       }
   90   
   91   
   92       /**
   93        * Prepare for evaluation of the body just before the first body evaluation:
   94        * no action.
   95        *
   96        * @throws JspException if an error occurred while processing this tag
   97        * @see #setBodyContent
   98        * @see #doAfterBody
   99        * @see BodyTag#doInitBody
  100        */
  101   
  102       public void doInitBody() throws JspException {
  103       }
  104   
  105   
  106       /**
  107        * After the body evaluation: do not reevaluate and continue with the page.
  108        * By default nothing is done with the bodyContent data (if any).
  109        *
  110        * @return SKIP_BODY
  111        * @throws JspException if an error occurred while processing this tag
  112        * @see #doInitBody
  113        * @see BodyTag#doAfterBody
  114        */
  115   
  116       public int doAfterBody() throws JspException {
  117    	return SKIP_BODY;
  118       }
  119   
  120   
  121       /**
  122        * Release state.
  123        *
  124        * @see Tag#release
  125        */
  126   
  127       public void release() {
  128   	bodyContent = null;
  129   
  130   	super.release();
  131       }
  132   
  133       /**
  134        * Get current bodyContent.
  135        *
  136        * @return the body content.
  137        */
  138       
  139       public BodyContent getBodyContent() {
  140   	return bodyContent;
  141       }
  142   
  143   
  144       /**
  145        * Get surrounding out JspWriter.
  146        *
  147        * @return the enclosing JspWriter, from the bodyContent.
  148        */
  149   
  150       public JspWriter getPreviousOut() {
  151   	return bodyContent.getEnclosingWriter();
  152       }
  153   
  154       // protected fields
  155   
  156       /**
  157        * The current BodyContent for this BodyTag.
  158        */
  159       protected BodyContent   bodyContent;
  160   }