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Java > Open Source Codes > org > jruby > util > IdUtil


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2  * Version: CPL 1.0/GPL 2.0/LGPL 2.1
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14  * Copyright (C) 2001-2002 Jan Arne Petersen <jpetersen@uni-bonn.de>
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28 package org.jruby.util;
29
30 public final class IdUtil {
31     public static final int CONSTANT = 0;
32     public static final int INSTANCE_VAR = 1;
33     public static final int CLASS_VAR = 2;
34     public static final int GLOBAL_VAR = 4;
35     public static final int LOCAL_VAR = 8;
36     
37     /**
38      * Get type of variable based on Ruby naming conventions. This is useful when you know
39      * you are going to want to know what type it is. It should in theory be cheaper than
40      * calling all the isFoo methods seperately. It also should be faster than isLocal.
41      *
42      * @param id the name to determine its type from
43      * @return value representing the type.
44      */
45     public static int getVarType(String JavaDoc id) {
46         char c = id.charAt(0);
47         
48         switch (c) {
49         case '@':
50             return id.charAt(1) == '@' ? CLASS_VAR : INSTANCE_VAR;
51         case '$':
52             return GLOBAL_VAR;
53         }
54         
55         return Character.isUpperCase(c) ? CONSTANT : LOCAL_VAR;
56     }
57
58     /**
59      * rb_is_const_id and is_const_id
60      */
61     public static boolean isConstant(String JavaDoc id) {
62         return Character.isUpperCase(id.charAt(0));
63     }
64
65     /**
66      * rb_is_class_id and is_class_id
67      */
68     public static boolean isClassVariable(String JavaDoc id) {
69         return id.length()>1 && id.charAt(0) == '@' && id.charAt(1) == '@';
70     }
71
72     /**
73      * rb_is_instance_id and is_instance_id
74      */
75     public static boolean isInstanceVariable(String JavaDoc id) {
76         return id.length()>0 && id.charAt(0) == '@' && (id.length() < 2 || id.charAt(1) != '@');
77     }
78     
79     /**
80      * rb_is_global_id and is_global_id
81      */
82     public static boolean isGlobal(String JavaDoc id) {
83         return id.length()>0 && id.charAt(0) == '$';
84     }
85     
86     /**
87      * rb_is_local_id and is_local_id
88      */
89     public static boolean isLocal(String JavaDoc id) {
90         return !isGlobal(id) && !isClassVariable(id) && !isInstanceVariable(id) && !isConstant(id);
91     }
92
93     public static boolean isAttrSet(String JavaDoc id) {
94         return id.endsWith("=");
95     }
96 }
97
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