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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 java.io.Writer;
23  
24  import org.apache.velocity.context.InternalContextAdapter;
25  import org.apache.velocity.exception.VelocityException;
26  import org.apache.velocity.runtime.RuntimeServices;
27  import org.apache.velocity.runtime.log.Log;
28  import org.apache.velocity.runtime.parser.node.Node;
29  
30  /**
31   * This class implements the #stop directive which allows
32   * a user to stop the merging and rendering process. The #stop directive
33   * will accept a single message argument with info about the reason for
34   * stopping.
35   */
36  public class Stop extends Directive
37  {  
38      private static final StopCommand STOP_ALL = new StopCommand("StopCommand to exit merging");
39  
40      private boolean hasMessage = false;
41  
42      /**
43       * Return name of this directive.
44       * @return The name of this directive.
45       */
46      public String getName()
47      {
48          return "stop";
49      }
50  
51      /**
52       * Return type of this directive.
53       * @return The type of this directive.
54       */
55      public int getType()
56      {
57          return LINE;
58      }
59  
60      /**
61       * Since there is no processing of content,
62       * there is never a need for an internal scope.
63       */
64      public boolean isScopeProvided()
65      {
66          return false;
67      }
68  
69      public void init(RuntimeServices rs, InternalContextAdapter context, Node node)
70      {
71          super.init(rs, context, node);
72  
73          int kids = node.jjtGetNumChildren();
74          if (kids > 1)
75          {  
76              throw new VelocityException("The #stop directive only accepts a single message parameter at "
77                   + Log.formatFileString(this));
78          }
79          else
80          {
81              hasMessage = (kids == 1);
82          }
83      }
84  
85      public boolean render(InternalContextAdapter context, Writer writer, Node node)
86      {
87          if (!hasMessage)
88          {
89              throw STOP_ALL;
90          }
91  
92          Object argument = node.jjtGetChild(0).value(context);
93  
94          // stop all and use specified message
95          throw new StopCommand(String.valueOf(argument));
96      }
97  
98  }
99