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    1   /*
    2    * $Id: StrutsBodyTagSupport.java 540552 2007-05-22 12:13:00Z mrdon $
    3    *
    4    * Licensed to the Apache Software Foundation (ASF) under one
    5    * or more contributor license agreements.  See the NOTICE file
    6    * distributed with this work for additional information
    7    * regarding copyright ownership.  The ASF licenses this file
    8    * to you under the Apache License, Version 2.0 (the
    9    * "License"); you may not use this file except in compliance
   10    * with the License.  You may obtain a copy of the License at
   11    *
   12    *  http://www.apache.org/licenses/LICENSE-2.0
   13    *
   14    * Unless required by applicable law or agreed to in writing,
   15    * software distributed under the License is distributed on an
   16    * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   17    * KIND, either express or implied.  See the License for the
   18    * specific language governing permissions and limitations
   19    * under the License.
   20    */
   21   package org.apache.struts2.views.jsp;
   22   
   23   import java.io.PrintWriter;
   24   
   25   import javax.servlet.jsp.tagext.BodyTagSupport;
   26   
   27   import org.apache.struts2.util.FastByteArrayOutputStream;
   28   import org.apache.struts2.views.annotations.StrutsTagAttribute;
   29   import org.apache.struts2.views.util.ContextUtil;
   30   
   31   import com.opensymphony.xwork2.util.ValueStack;
   32   
   33   
   34   /**
   35    * Contains common functonalities for Struts JSP Tags.
   36    *
   37    */
   38   public class StrutsBodyTagSupport extends BodyTagSupport {
   39   
   40       private static final long serialVersionUID = -1201668454354226175L;
   41   
   42       @StrutsTagAttribute(required=false,description="The id of the tag element")
   43       public void setId(String string) {
   44           super.setId(string);
   45       }
   46   
   47       protected boolean altSyntax() {
   48           return ContextUtil.isUseAltSyntax(getStack().getContext());
   49       }
   50   
   51       protected ValueStack getStack() {
   52           return TagUtils.getStack(pageContext);
   53       }
   54   
   55       protected String findString(String expr) {
   56           return (String) findValue(expr, String.class);
   57       }
   58   
   59       protected Object findValue(String expr) {
   60           if (altSyntax()) {
   61               // does the expression start with %{ and end with }? if so, just cut it off!
   62               if (expr.startsWith("%{") && expr.endsWith("}")) {
   63                   expr = expr.substring(2, expr.length() - 1);
   64               }
   65           }
   66   
   67           return getStack().findValue(expr);
   68       }
   69   
   70       protected Object findValue(String expr, Class toType) {
   71           if (altSyntax() && toType == String.class) {
   72               return translateVariables(expr, getStack());
   73           } else {
   74               if (altSyntax()) {
   75                   // does the expression start with %{ and end with }? if so, just cut it off!
   76                   if (expr.startsWith("%{") && expr.endsWith("}")) {
   77                       expr = expr.substring(2, expr.length() - 1);
   78                   }
   79               }
   80   
   81               return getStack().findValue(expr, toType);
   82           }
   83       }
   84   
   85       protected String toString(Throwable t) {
   86           FastByteArrayOutputStream bout = new FastByteArrayOutputStream();
   87           PrintWriter wrt = new PrintWriter(bout);
   88           t.printStackTrace(wrt);
   89           wrt.close();
   90   
   91           return bout.toString();
   92       }
   93   
   94       protected String getBody() {
   95           if (bodyContent == null) {
   96               return "";
   97           } else {
   98               return bodyContent.getString().trim();
   99           }
  100       }
  101   
  102       public static String translateVariables(String expression, ValueStack stack) {
  103           while (true) {
  104               int x = expression.indexOf("%{");
  105               int y = expression.indexOf("}", x);
  106   
  107               if ((x != -1) && (y != -1)) {
  108                   String var = expression.substring(x + 2, y);
  109   
  110                   Object o = stack.findValue(var, String.class);
  111   
  112                   if (o != null) {
  113                       expression = expression.substring(0, x) + o + expression.substring(y + 1);
  114                   } else {
  115                       // the variable doesn't exist, so don't display anything
  116                       expression = expression.substring(0, x) + expression.substring(y + 1);
  117                   }
  118               } else {
  119                   break;
  120               }
  121           }
  122   
  123           return expression;
  124       }
  125   }

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