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 import org.apache.velocity.runtime.directive.Evaluate;
25
26 /**
27 * Stop command for directive Control objects. In an ideal JDK,
28 * this would be able to extend a RuntimeThrowable class, but we
29 * don't have that. So to avoid the interface changes needed by
30 * extending Throwable and the potential errant catches were we
31 * to extend RuntimeException, we'll have to extend Error,
32 * despite the fact that this is never an error.
33 *
34 * @author Nathan Bubna
35 * @version $Id$
36 */
37 public class StopCommand extends Error
38 {
39 private static final long serialVersionUID = 2577683435802825964L;
40 private Object stopMe;
41 private boolean nearest = false;
42
43 public StopCommand()
44 {
45 this.nearest = true;
46 }
47
48 public StopCommand(String message)
49 {
50 super(message);
51 }
52
53 public StopCommand(Object stopMe)
54 {
55 this.stopMe = stopMe;
56 }
57
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
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 that instanceof Evaluate);
88 }
89 }
90 }