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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  }