1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.jxpath.ri.compiler;
19
20 import org.apache.commons.jxpath.ri.EvalContext;
21 import org.apache.commons.jxpath.ri.InfoSetUtil;
22
23 /**
24 * Implementation of {@link Expression} for the operation unary "-".
25 */
26 public class CoreOperationNegate extends CoreOperation {
27
28 /**
29 * Constructs a new CoreOperationNegate.
30 *
31 * @param arg the Expression to negate
32 */
33 public CoreOperationNegate(final Expression arg) {
34 super(new Expression[] { arg });
35 }
36
37 @Override
38 public Object computeValue(final EvalContext context) {
39 final double a = InfoSetUtil.doubleValue(args[0].computeValue(context));
40 return Double.valueOf(-a);
41 }
42
43 @Override
44 protected int getPrecedence() {
45 return NEGATE_PRECEDENCE;
46 }
47
48 @Override
49 public String getSymbol() {
50 return "-";
51 }
52
53 @Override
54 protected boolean isSymmetric() {
55 return false;
56 }
57 }