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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.impl;
    17
    18  import org.apache.commons.jelly.JellyContext;
    19  import org.apache.commons.jelly.JellyTagException;
    20  import org.apache.commons.jelly.Script;
    21  import org.apache.commons.jelly.XMLOutput;
    22  import org.apache.commons.jelly.expression.Expression;
    23
    24  import org.xml.sax.SAXException;
    25
    26  /***
    27   * <p><code>ExpressionScript</code> outputs the value of an expression as text.</p>
    28   *
    29   * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
    30   * @version $Revision: 155420 $
    31   */
    32  public class ExpressionScript implements Script {
    33
    34      /*** the expression evaluated as a String and output by this script */
    35      private Expression expression;
    36
    37      public ExpressionScript() {
    38      }
    39
    40      public ExpressionScript(Expression expression) {
    41          this.expression = expression;
    42      }
    43
    44      public String toString() {
    45          return super.toString() + "[expression=" + expression + "]";
    46      }
    47
    48      /*** @return the expression evaluated as a String and output by this script */
    49      public Expression getExpression() {
    50          return expression;
    51      }
    52
    53      /*** Sets the expression evaluated as a String and output by this script */
    54      public void setExpression(Expression expression) {
    55          this.expression = expression;
    56      }
    57
    58      // Script interface
    59      //-------------------------------------------------------------------------
    60      public Script compile() {
    61          return this;
    62      }
    63
    64      /*** Evaluates the body of a tag */
    65      public void run(JellyContext context, XMLOutput output) throws JellyTagException {
    66          Object result = expression.evaluate(context);
    67          if ( result != null ) {
    68
    69              try {
    70                output.objectData(result);
    71              } catch (SAXException e) {
    72                  throw new JellyTagException("Could not write to XMLOutput",e);
    73              }
    74
    75          }
    76      }
    77  }