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    1   /*
    2    * Copyright 1999-2004 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.jxpath.ri.compiler;
    17
    18  import org.apache.commons.jxpath.ri.EvalContext;
    19
    20  /***
    21   * A compile tree element containing a constant number or string.
    22   *
    23   * @author Dmitri Plotnikov
    24   * @version $Revision: 1.8 $ $Date: 2004/02/29 14:17:39 $
    25   */
    26  public class Constant extends Expression {
    27
    28      private Object value;
    29
    30      public Constant(Number number) {
    31          this.value = number;
    32      }
    33
    34      public Constant(String string) {
    35          this.value = string;
    36      }
    37
    38      public Object compute(EvalContext context) {
    39          return value;
    40      }
    41
    42      /***
    43       * Returns the value of the constant.
    44       */
    45      public Object computeValue(EvalContext context) {
    46          return value;
    47      }
    48
    49      /***
    50       * Returns false
    51       */
    52      public boolean isContextDependent() {
    53          return false;
    54      }
    55
    56      /***
    57       * Returns false
    58       */
    59      public boolean computeContextDependent() {
    60          return false;
    61      }
    62
    63      public String toString() {
    64          if (value instanceof Number) {
    65              double doubleValue = ((Number) value).doubleValue();
    66              long longValue = ((Number) value).longValue();
    67              if (doubleValue == longValue) {
    68                  return String.valueOf(longValue);
    69              }
    70              else {
    71                  return String.valueOf(doubleValue);
    72              }
    73          }
    74          else {
    75              return "'" + value + "'";
    76          }
    77      }
    78  }