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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 final class When implements TagPlugin {
25  
26      public void doTag(TagPluginContext ctxt) {
27          // Get the parent context to determine if this is the first <c:when>
28          TagPluginContext parentContext = ctxt.getParentContext();
29          if (parentContext == null) {
30              ctxt.dontUseTagPlugin();
31              return;
32          }
33  
34          if ("true".equals(parentContext.getPluginAttribute("hasBeenHere"))) {
35              ctxt.generateJavaSource("} else if(");
36              // See comment below for the reason we generate the extra "}" here.
37          } else {
38              ctxt.generateJavaSource("if(");
39              parentContext.setPluginAttribute("hasBeenHere", "true");
40          }
41          ctxt.generateAttribute("test");
42          ctxt.generateJavaSource("){");
43          ctxt.generateBody();
44  
45          // We don't generate the closing "}" for the "if" here because there
46          // may be whitespaces in between <c:when>'s.  Instead we delay
47          // generating it until the next <c:when> or <c:otherwise> or
48          // <c:choose>
49      }
50  }