KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > com > google > gwt > dev > js > ast > JsOperator


1 /*
2  * Copyright 2007 Google Inc.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License"); you may not
5  * use this file except in compliance with the License. You may obtain a copy of
6  * 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, WITHOUT
12  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13  * License for the specific language governing permissions and limitations under
14  * the License.
15  */
16 package com.google.gwt.dev.js.ast;
17
18 /**
19  * A JavaScript operator.
20  */
21 public abstract class JsOperator {
22
23   protected static final int LEFT = 0x01;
24   protected static final int INFIX = 0x02;
25   protected static final int POSTFIX = 0x04;
26   protected static final int PREFIX = 0x08;
27
28   private final int mask;
29
30   private final int precedence;
31
32   private final String JavaDoc symbol;
33
34   protected JsOperator(String JavaDoc symbol, int precedence, int mask) {
35     this.symbol = symbol;
36     this.precedence = precedence;
37     this.mask = mask;
38   }
39
40   public int getPrecedence() {
41     return precedence;
42   }
43
44   public String JavaDoc getSymbol() {
45     return symbol;
46   }
47
48   public abstract boolean isKeyword();
49
50   public boolean isLeftAssociative() {
51     return (mask & LEFT) != 0;
52   }
53
54   public boolean isPrecedenceLessThan(JsOperator other) {
55     return precedence < other.precedence;
56   }
57
58   public boolean isValidInfix() {
59     return (mask & INFIX) != 0;
60   }
61
62   public boolean isValidPostfix() {
63     return (mask & POSTFIX) != 0;
64   }
65
66   public boolean isValidPrefix() {
67     return (mask & PREFIX) != 0;
68   }
69
70   public String JavaDoc toString() {
71     return symbol;
72   }
73 }
74
Popular Tags