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1   /*
2    * Copyright 2002,2004 The Apache Software Foundation.
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.apache.commons.jelly.tags.define;
17  
18  import org.apache.commons.jelly.JellyTagException;
19  import org.apache.commons.jelly.MissingAttributeException;
20  import org.apache.commons.jelly.Script;
21  import org.apache.commons.jelly.TagSupport;
22  import org.apache.commons.jelly.XMLOutput;
23  import org.apache.commons.logging.Log;
24  import org.apache.commons.logging.LogFactory;
25  
26  /***
27   * The <invoke> tag will invoke a given Script instance.
28   * It can be used with the <script> tag which defines scripts
29   * as variables that can later be invoked by this <invoke> tag.
30   *
31   * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
32   * @version $Revision: 155420 $
33   */
34  public class InvokeTag extends TagSupport {
35  
36      /*** The Log to which logging calls will be made. */
37      private static final Log log = LogFactory.getLog(InvokeTag.class);
38  
39      private Script script;
40  
41  
42      public InvokeTag() {
43      }
44  
45      /***
46       * Sets the Script to be invoked by this tag, which typically has been previously
47       * defined by the use of the &lt;script&gt; tag.
48       */
49      public void setScript(Script script) {
50          this.script = script;
51      }
52  
53      // Tag interface
54      //-------------------------------------------------------------------------
55      public void doTag(XMLOutput output) throws MissingAttributeException, JellyTagException {
56          if ( script == null ) {
57              throw new MissingAttributeException("script");
58          }
59          script.run(context, output);
60      }
61  }