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Java > Open Source Codes > org > apache > tapestry > script > InputSymbolToken


1 // Copyright 2004, 2005 The Apache Software Foundation
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 package org.apache.tapestry.script;
16
17 import org.apache.hivemind.ApplicationRuntimeException;
18 import org.apache.hivemind.Location;
19 import org.apache.tapestry.Tapestry;
20
21 /**
22  * A token that validates that an input symbol exists or is of a
23  * declared type.
24  *
25  *
26  * @author Howard Lewis Ship
27  * @since 2.2
28  *
29  **/
30
31 class InputSymbolToken extends AbstractToken
32 {
33     private String JavaDoc _key;
34     private Class JavaDoc _class;
35     private boolean _required;
36
37     InputSymbolToken(String JavaDoc key, Class JavaDoc clazz, boolean required, Location location)
38     {
39         super(location);
40
41         _key = key;
42         _class = clazz;
43         _required = required;
44     }
45
46     public void write(StringBuffer JavaDoc buffer, ScriptSession session)
47     {
48         Object JavaDoc value = session.getSymbols().get(_key);
49
50         if (_required && value == null)
51             throw new ApplicationRuntimeException(
52                 Tapestry.format("InputSymbolToken.required", _key),
53                 getLocation(),
54                 null);
55
56         if (value != null && _class != null && !_class.isAssignableFrom(value.getClass()))
57             throw new ApplicationRuntimeException(
58                 Tapestry.format(
59                     "InputSymbolToken.wrong-type",
60                     _key,
61                     value.getClass().getName(),
62                     _class.getName()),
63                 getLocation(),
64                 null);
65     }
66
67 }
68
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