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    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  import org.apache.commons.jexl.util.Coercion;
    21
    22  /***
    23   * LT : a < b.
    24   *
    25   * Follows A.3.6.1 of the JSTL 1.0 specification
    26   *
    27   * @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
    28   * @author <a href="mailto:proyal@apache.org">Peter Royal</a>
    29   * @version $Id: ASTLTNode.java 398203 2006-04-29 16:44:55Z dion $
    30   */
    31  public class ASTLTNode extends SimpleNode {
    32      /***
    33       * Create the node given an id.
    34       *
    35       * @param id node id.
    36       */
    37      public ASTLTNode(int id) {
    38          super(id);
    39      }
    40
    41      /***
    42       * Create a node with the given parser and id.
    43       *
    44       * @param p a parser.
    45       * @param id node id.
    46       */
    47      public ASTLTNode(Parser p, int id) {
    48          super(p, id);
    49      }
    50
    51      /*** {@inheritDoc} */
    52      public Object jjtAccept(ParserVisitor visitor, Object data) {
    53          return visitor.visit(this, data);
    54      }
    55
    56      /*** {@inheritDoc} */
    57      public Object value(JexlContext jc) throws Exception {
    58          /*
    59           * now get the values
    60           */
    61
    62          Object left = ((SimpleNode) jjtGetChild(0)).value(jc);
    63          Object right = ((SimpleNode) jjtGetChild(1)).value(jc);
    64
    65          if ((left == right) || (left == null) || (right == null)) {
    66              return Boolean.FALSE;
    67          } else if (Coercion.isFloatingPoint(left)
    68                  || Coercion.isFloatingPoint(right)) {
    69              double leftDouble = Coercion.coerceDouble(left).doubleValue();
    70              double rightDouble = Coercion.coerceDouble(right).doubleValue();
    71
    72              return leftDouble < rightDouble ? Boolean.TRUE : Boolean.FALSE;
    73          } else if (Coercion.isNumberable(left) || Coercion.isNumberable(right)) {
    74              long leftLong = Coercion.coerceLong(left).longValue();
    75              long rightLong = Coercion.coerceLong(right).longValue();
    76
    77              return leftLong < rightLong ? Boolean.TRUE : Boolean.FALSE;
    78          } else if (left instanceof String || right instanceof String) {
    79              String leftString = left.toString();
    80              String rightString = right.toString();
    81
    82              return leftString.compareTo(rightString) < 0 ? Boolean.TRUE
    83                      : Boolean.FALSE;
    84          } else if (left instanceof Comparable) {
    85              return ((Comparable) left).compareTo(right) < 0 ? Boolean.TRUE
    86                      : Boolean.FALSE;
    87          } else if (right instanceof Comparable) {
    88              return ((Comparable) right).compareTo(left) > 0 ? Boolean.TRUE
    89                      : Boolean.FALSE;
    90          }
    91
    92          throw new Exception("Invalid comparison : LT ");
    93      }
    94  }