View Javadoc

    1   /*
    2    * Copyright 2002-2006 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
    17  package org.apache.commons.jexl.parser;
    18
    19  import org.apache.commons.jexl.JexlContext;
    20
    21  /***
    22   * x = y, assigns a value to a variable in the context.
    23   *
    24   * @author Dion Gillard
    25   *
    26   */
    27  public class ASTAssignment extends SimpleNode {
    28      /***
    29       * Create the node given an id.
    30       *
    31       * @param id node id.
    32       */
    33      public ASTAssignment(int id) {
    34          super(id);
    35      }
    36
    37      /***
    38       * Create a node with the given parser and id.
    39       *
    40       * @param p a parser.
    41       * @param id node id.
    42       */
    43      public ASTAssignment(Parser p, int id) {
    44          super(p, id);
    45      }
    46
    47      /*** {@inheritDoc} */
    48      public Object jjtAccept(ParserVisitor visitor, Object data) {
    49          return visitor.visit(this, data);
    50      }
    51
    52      /*** {@inheritDoc} */
    53      public Object value(JexlContext context) throws Exception {
    54          // left should be the variable (reference) to assign to
    55          SimpleNode left = (SimpleNode) jjtGetChild(0);
    56          // right should be the expression to evaluate
    57          Object right = ((SimpleNode) jjtGetChild(1)).value(context);
    58          if (left instanceof ASTReference) {
    59              ASTReference reference = (ASTReference) left;
    60              left = (SimpleNode) reference.jjtGetChild(0);
    61              if (left instanceof ASTIdentifier) {
    62                  String identifier = ((ASTIdentifier) left)
    63                          .getIdentifierString();
    64                  context.getVars().put(identifier, right);
    65              }
    66          }
    67          return right;
    68      }
    69  }