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Java > Open Source Codes > org > apache > jasper > tagplugins > jstl > core > When


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.jasper.tagplugins.jstl.core;
20
21 import org.apache.jasper.compiler.tagplugin.*;
22
23 public final class When implements TagPlugin {
24     
25     public void doTag(TagPluginContext ctxt) {
26         // Get the parent context to determine if this is the first <c:when>
27 TagPluginContext parentContext = ctxt.getParentContext();
28         if (parentContext == null) {
29             ctxt.dontUseTagPlugin();
30             return;
31         }
32         
33         if ("true".equals(parentContext.getPluginAttribute("hasBeenHere"))) {
34             ctxt.generateJavaSource("} else if(");
35             // See comment below for the reason we generate the extra "}" here.
36 }
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 }
51
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