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1 package org.apache.velocity.runtime.directive;
2 
3 /*
4  * Licensed to the Apache Software Foundation (ASF) under one
5  * or more contributor license agreements.  See the NOTICE file
6  * distributed with this work for additional information
7  * regarding copyright ownership.  The ASF licenses this file
8  * to you under the Apache License, Version 2.0 (the
9  * "License"); you may not use this file except in compliance
10  * with the License.  You may obtain a copy of the License at
11  *
12  *   http://www.apache.org/licenses/LICENSE-2.0
13  *
14  * Unless required by applicable law or agreed to in writing,
15  * software distributed under the License is distributed on an
16  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17  * KIND, either express or implied.  See the License for the
18  * specific language governing permissions and limitations
19  * under the License.
20  */
21 
22 import org.apache.velocity.Template;
23 import org.apache.velocity.runtime.RuntimeInstance;
24 
25 /**
26  * Stop command for directive Control objects.  In an ideal JDK,
27  * this would be able to extend a RuntimeThrowable class, but we
28  * don't have that. So to avoid the interface changes needed by
29  * extending Throwable and the potential errant catches were we
30  * to extend RuntimeException, we'll have to extend Error,
31  * despite the fact that this is never an error.
32  *
33  * @author Nathan Bubna
34  * @version $Id$
35  */
36 public class StopCommand extends Error
37 {
38     private static final long serialVersionUID = 2577683435802825964L;
39     private Object stopMe;
40     private boolean nearest = false;
41 
StopCommand()42     public StopCommand()
43     {
44         this.nearest = true;
45     }
46 
StopCommand(String message)47     public StopCommand(String message)
48     {
49         super(message);
50     }
51 
StopCommand(Object stopMe)52     public StopCommand(Object stopMe)
53     {
54         this.stopMe = stopMe;
55     }
56 
57     @Override
getMessage()58     public String getMessage()
59     {
60         if (stopMe != null)
61         {
62             // only create a useful message if requested (which is unlikely)
63             return "StopCommand: "+stopMe;
64         }
65         else
66         {
67             return "StopCommand: "+super.getMessage();
68         }
69     }
70 
isFor(Object that)71     public boolean isFor(Object that)
72     {
73         if (nearest) // if we're stopping at the first chance
74         {
75             // save that for message
76             stopMe = that;
77             return true;
78         }
79         else if (stopMe != null) // if we have a specified stopping point
80         {
81             return (that == stopMe);
82         }
83         else // only stop for the top :)
84         {
85             return (that instanceof Template ||
86                     that instanceof RuntimeInstance);
87         }
88     }
89 }
90