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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.core;
    17
    18  import java.io.FileOutputStream;
    19  import java.io.IOException;
    20  import java.io.UnsupportedEncodingException;
    21
    22  import org.apache.commons.jelly.JellyContext;
    23  import org.apache.commons.jelly.JellyTagException;
    24  import org.apache.commons.jelly.TagSupport;
    25  import org.apache.commons.jelly.XMLOutput;
    26  import org.apache.commons.logging.Log;
    27  import org.apache.commons.logging.LogFactory;
    28
    29  /*** A tag that spawns the contained script in a separate thread
    30    *
    31    * @author <a href="mailto:vinayc@apache.org">Vinay Chandran</a>
    32    */
    33  public class ThreadTag extends TagSupport  {
    34      /*** Thread Name */
    35      private String name = null;
    36      /*** the destination of output */
    37      private XMLOutput xmlOutput;
    38      /*** Should we close the underlying output */
    39      private boolean closeOutput;
    40      /*** The Log to which logging calls will be made. */
    41      private static final Log log = LogFactory.getLog(ThreadTag.class);
    42
    43      public ThreadTag() {
    44      }
    45
    46      // Tag interface
    47      //-------------------------------------------------------------------------
    48      public void doTag(final XMLOutput output) throws JellyTagException {
    49          if ( xmlOutput == null ) {
    50              // lets default to system.out
    51              try {
    52                  xmlOutput = XMLOutput.createXMLOutput( System.out );
    53              } catch (UnsupportedEncodingException e) {
    54                  throw new JellyTagException(e);
    55              }
    56          }
    57
    58          // lets create a child context
    59          final JellyContext newContext = context.newJellyContext();
    60
    61          Thread thread = new Thread(
    62              new Runnable() {
    63                  public void run() {
    64                      try {
    65                          getBody().run(newContext, xmlOutput);
    66                          if (closeOutput) {
    67                              xmlOutput.close();
    68                          }
    69                          else {
    70                              xmlOutput.flush();
    71                          }
    72                      }
    73                      catch (Exception e) {
    74                          if (log.isErrorEnabled()) log.error("error running thread tag", e);
    75                      }
    76                  }
    77              }
    78          );
    79          if ( name != null ) {
    80              thread.setName( name );
    81          }
    82          thread.start();
    83      }
    84
    85      /***
    86       * Sets the name of the thread.
    87       * @param name The name to set
    88       */
    89      public void setName(String name) {
    90          this.name = name;
    91      }
    92
    93      /***
    94       * Sets the destination of output
    95       */
    96      public void setXmlOutput(XMLOutput xmlOutput) {
    97          this.closeOutput = false;
    98          this.xmlOutput = xmlOutput;
    99      }
    100
    101     /***
    102      * Set the file which is generated from the output
    103      * @param name The output file name
    104      */
    105     public void setFile(String name) throws IOException {
    106         this.closeOutput = true;
    107         setXmlOutput( XMLOutput.createXMLOutput(new FileOutputStream(name)) );
    108     }
    109 }