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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  import org.apache.commons.jelly.expression.Expression;
    22  import org.xml.sax.SAXException;
    23
    24  /*** A tag which evaluates an expression
    25    *
    26    * @tag out
    27    * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
    28    * @version $Revision: 155420 $
    29    */
    30  public class ExprTag extends TagSupport {
    31
    32      /*** The expression to evaluate. */
    33      private Expression value;
    34
    35      public ExprTag() {
    36      }
    37
    38      // Tag interface
    39      //-------------------------------------------------------------------------
    40      public void doTag(XMLOutput output) throws JellyTagException {
    41          if (value != null) {
    42              String text = value.evaluateAsString(context);
    43              if (text != null) {
    44
    45                  try {
    46                      output.write(text);
    47                  }
    48                  catch (SAXException e) {
    49                      throw new JellyTagException("could not write the XMLOutput",e);
    50                  }
    51              }
    52          }
    53      }
    54
    55      // Properties
    56      //-------------------------------------------------------------------------
    57
    58      /***
    59       * Sets the Jexl expression to evaluate.
    60       *
    61       * @required true
    62       */
    63      public void setValue(Expression value) {
    64          this.value = value;
    65      }
    66  }