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    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   
   18   
   19   package org.apache.struts2.jasper.tagplugins.jstl.core;
   20   
   21   import org.apache.struts2.jasper.compiler.tagplugin.TagPlugin;
   22   import org.apache.struts2.jasper.compiler.tagplugin.TagPluginContext;
   23   
   24   public class Param implements TagPlugin {
   25   
   26       public void doTag(TagPluginContext ctxt) {
   27   
   28           //don't support the body content
   29   
   30           //define names of all the temp variables
   31           String nameName = ctxt.getTemporaryVariableName();
   32           String valueName = ctxt.getTemporaryVariableName();
   33           String urlName = ctxt.getTemporaryVariableName();
   34           String encName = ctxt.getTemporaryVariableName();
   35           String index = ctxt.getTemporaryVariableName();
   36   
   37           //if the param tag has no parents, throw a exception
   38           TagPluginContext parent = ctxt.getParentContext();
   39           if (parent == null) {
   40               ctxt.generateJavaSource(" throw new JspTagExcption" +
   41                       "(\"<param> outside <import> or <urlEncode>\");");
   42               return;
   43           }
   44   
   45           //get the url string before adding this param
   46           ctxt.generateJavaSource("String " + urlName + " = " +
   47                   "(String)pageContext.getAttribute(\"url_without_param\");");
   48   
   49           //get the value of "name"
   50           ctxt.generateJavaSource("String " + nameName + " = ");
   51           ctxt.generateAttribute("name");
   52           ctxt.generateJavaSource(";");
   53   
   54           //if the "name" is null then do nothing.
   55           //else add such string "name=value" to the url.
   56           //and the url should be encoded
   57           ctxt.generateJavaSource("if(" + nameName + " != null && !" + nameName + ".equals(\"\")){");
   58           ctxt.generateJavaSource("    String " + valueName + " = ");
   59           ctxt.generateAttribute("value");
   60           ctxt.generateJavaSource(";");
   61           ctxt.generateJavaSource("    if(" + valueName + " == null) " + valueName + " = \"\";");
   62           ctxt.generateJavaSource("    String " + encName + " = pageContext.getResponse().getCharacterEncoding();");
   63           ctxt.generateJavaSource("    " + nameName + " = java.net.URLEncoder.encode(" + nameName + ", " + encName + ");");
   64           ctxt.generateJavaSource("    " + valueName + " = java.net.URLEncoder.encode(" + valueName + ", " + encName + ");");
   65           ctxt.generateJavaSource("    int " + index + ";");
   66           ctxt.generateJavaSource("    " + index + " = " + urlName + ".indexOf(\'?\');");
   67           //if the current param is the first one, add a "?" ahead of it
   68           //else add a "&" ahead of it
   69           ctxt.generateJavaSource("    if(" + index + " == -1){");
   70           ctxt.generateJavaSource("        " + urlName + " = " + urlName + " + \"?\" + " + nameName + " + \"=\" + " + valueName + ";");
   71           ctxt.generateJavaSource("    }else{");
   72           ctxt.generateJavaSource("        " + urlName + " = " + urlName + " + \"&\" + " + nameName + " + \"=\" + " + valueName + ";");
   73           ctxt.generateJavaSource("    }");
   74           ctxt.generateJavaSource("    pageContext.setAttribute(\"url_without_param\"," + urlName + ");");
   75           ctxt.generateJavaSource("}");
   76       }
   77   }

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