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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 org.apache.commons.jelly.JellyTagException;
    19  import org.apache.commons.jelly.TagSupport;
    20  import org.apache.commons.jelly.XMLOutput;
    21
    22  /***
    23   * A tag which catches exceptions thrown by its body.
    24   * This allows conditional logic to be performed based on if exceptions
    25   * are thrown or to do some kind of custom exception logging logic.
    26   *
    27   * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
    28   * @version $Revision: 155420 $
    29   */
    30  public class CatchTag extends TagSupport {
    31
    32      private String var;
    33
    34      public CatchTag() {
    35      }
    36
    37      // Tag interface
    38      //-------------------------------------------------------------------------
    39      public void doTag(XMLOutput output) throws JellyTagException {
    40          if (var != null) {
    41              context.removeVariable(var);
    42          }
    43          try {
    44              invokeBody(output);
    45          }
    46          catch (Throwable t) {
    47              if (var != null) {
    48                  context.setVariable(var, t);
    49              }
    50          }
    51      }
    52
    53      // Properties
    54      //-------------------------------------------------------------------------
    55
    56      /***
    57       * Sets the name of the variable which is exposed with the Exception that gets
    58       * thrown by evaluating the body of this tag or which is set to null if there is
    59       * no exception thrown.
    60       */
    61      public void setVar(String var) {
    62          this.var = var;
    63      }
    64  }