Flags.java revision 2839:592d64800143 
1/*
2 * Copyright (c) 1999, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
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24 */
25
26package com.sun.tools.javac.code;
27
28import java.util.Collections;
29import java.util.EnumSet;
30import java.util.Map;
31import java.util.Set;
32import java.util.concurrent.ConcurrentHashMap;
33
34import javax.lang.model.element.Modifier;
35
36import com.sun.tools.javac.util.Assert;
37import com.sun.tools.javac.util.StringUtils;
38
39/** Access flags and other modifiers for Java classes and members.
40 *
41 *  <p><b>This is NOT part of any supported API.
42 *  If you write code that depends on this, you do so at your own risk.
43 *  This code and its internal interfaces are subject to change or
44 *  deletion without notice.</b>
45 */
46public class Flags {
47
48    private Flags() {} // uninstantiable
49
50    public static String toString(long flags) {
51        StringBuilder buf = new StringBuilder();
52        String sep = "";
53        for (Flag flag : asFlagSet(flags)) {
54            buf.append(sep);
55            buf.append(flag);
56            sep = " ";
57        }
58        return buf.toString();
59    }
60
61    public static EnumSet<Flag> asFlagSet(long flags) {
62        EnumSet<Flag> flagSet = EnumSet.noneOf(Flag.class);
63        for (Flag flag : Flag.values()) {
64            if ((flags & flag.value) != 0) {
65                flagSet.add(flag);
66                flags &= ~flag.value;
67            }
68        }
69        Assert.check(flags == 0);
70        return flagSet;
71    }
72
73    /* Standard Java flags.
74     */
75    public static final int PUBLIC       = 1;
76    public static final int PRIVATE      = 1<<1;
77    public static final int PROTECTED    = 1<<2;
78    public static final int STATIC       = 1<<3;
79    public static final int FINAL        = 1<<4;
80    public static final int SYNCHRONIZED = 1<<5;
81    public static final int VOLATILE     = 1<<6;
82    public static final int TRANSIENT    = 1<<7;
83    public static final int NATIVE       = 1<<8;
84    public static final int INTERFACE    = 1<<9;
85    public static final int ABSTRACT     = 1<<10;
86    public static final int STRICTFP     = 1<<11;
87
88    /* Flag that marks a symbol synthetic, added in classfile v49.0. */
89    public static final int SYNTHETIC    = 1<<12;
90
91    /** Flag that marks attribute interfaces, added in classfile v49.0. */
92    public static final int ANNOTATION   = 1<<13;
93
94    /** An enumeration type or an enumeration constant, added in
95     *  classfile v49.0. */
96    public static final int ENUM         = 1<<14;
97
98    /** Added in SE8, represents constructs implicitly declared in source. */
99    public static final int MANDATED     = 1<<15;
100
101    public static final int StandardFlags = 0x0fff;
102
103    // Because the following access flags are overloaded with other
104    // bit positions, we translate them when reading and writing class
105    // files into unique bits positions: ACC_SYNTHETIC <-> SYNTHETIC,
106    // for example.
107    public static final int ACC_SUPER    = 0x0020;
108    public static final int ACC_BRIDGE   = 0x0040;
109    public static final int ACC_VARARGS  = 0x0080;
110
111    /*****************************************
112     * Internal compiler flags (no bits in the lower 16).
113     *****************************************/
114
115    /** Flag is set if symbol is deprecated.
116     */
117    public static final int DEPRECATED   = 1<<17;
118
119    /** Flag is set for a variable symbol if the variable's definition
120     *  has an initializer part.
121     */
122    public static final int HASINIT          = 1<<18;
123
124    /** Flag is set for compiler-generated anonymous method symbols
125     *  that `own' an initializer block.
126     */
127    public static final int BLOCK            = 1<<20;
128
129    /** Flag is set for compiler-generated abstract methods that implement
130     *  an interface method (Miranda methods).
131     */
132    public static final int IPROXY           = 1<<21;
133
134    /** Flag is set for nested classes that do not access instance members
135     *  or `this' of an outer class and therefore don't need to be passed
136     *  a this$n reference.  This value is currently set only for anonymous
137     *  classes in superclass constructor calls and only for pre 1.4 targets.
138     *  todo: use this value for optimizing away this$n parameters in
139     *  other cases.
140     */
141    public static final int NOOUTERTHIS  = 1<<22;
142
143    /** Flag is set for package symbols if a package has a member or
144     *  directory and therefore exists.
145     */
146    public static final int EXISTS           = 1<<23;
147
148    /** Flag is set for compiler-generated compound classes
149     *  representing multiple variable bounds
150     */
151    public static final int COMPOUND     = 1<<24;
152
153    /** Flag is set for class symbols if a class file was found for this class.
154     */
155    public static final int CLASS_SEEN   = 1<<25;
156
157    /** Flag is set for class symbols if a source file was found for this
158     *  class.
159     */
160    public static final int SOURCE_SEEN  = 1<<26;
161
162    /* State flags (are reset during compilation).
163     */
164
165    /** Flag for class symbols is set and later re-set as a lock in
166     *  Enter to detect cycles in the superclass/superinterface
167     *  relations.  Similarly for constructor call cycle detection in
168     *  Attr.
169     */
170    public static final int LOCKED           = 1<<27;
171
172    /** Flag for class symbols is set and later re-set to indicate that a class
173     *  has been entered but has not yet been attributed.
174     */
175    public static final int UNATTRIBUTED = 1<<28;
176
177    /** Flag for synthesized default constructors of anonymous classes.
178     */
179    public static final int ANONCONSTR   = 1<<29;
180
181    /** Flag for class symbols to indicate it has been checked and found
182     *  acyclic.
183     */
184    public static final int ACYCLIC          = 1<<30;
185
186    /** Flag that marks bridge methods.
187     */
188    public static final long BRIDGE          = 1L<<31;
189
190    /** Flag that marks formal parameters.
191     */
192    public static final long PARAMETER   = 1L<<33;
193
194    /** Flag that marks varargs methods.
195     */
196    public static final long VARARGS   = 1L<<34;
197
198    /** Flag for annotation type symbols to indicate it has been
199     *  checked and found acyclic.
200     */
201    public static final long ACYCLIC_ANN      = 1L<<35;
202
203    /** Flag that marks a generated default constructor.
204     */
205    public static final long GENERATEDCONSTR   = 1L<<36;
206
207    /** Flag that marks a hypothetical method that need not really be
208     *  generated in the binary, but is present in the symbol table to
209     *  simplify checking for erasure clashes - also used for 292 poly sig methods.
210     */
211    public static final long HYPOTHETICAL   = 1L<<37;
212
213    /**
214     * Flag that marks an internal proprietary class.
215     */
216    public static final long PROPRIETARY = 1L<<38;
217
218    /**
219     * Flag that marks a multi-catch parameter.
220     */
221    public static final long UNION = 1L<<39;
222
223    /**
224     * Flag that marks a special kind of bridge method (the ones that
225     * come from restricted supertype bounds).
226     */
227    public static final long OVERRIDE_BRIDGE = 1L<<40;
228
229    /**
230     * Flag that marks an 'effectively final' local variable.
231     */
232    public static final long EFFECTIVELY_FINAL = 1L<<41;
233
234    /**
235     * Flag that marks non-override equivalent methods with the same signature.
236     */
237    public static final long CLASH = 1L<<42;
238
239    /**
240     * Flag that marks either a default method or an interface containing default methods.
241     */
242    public static final long DEFAULT = 1L<<43;
243
244    /**
245     * Flag that marks class as auxiliary, ie a non-public class following
246     * the public class in a source file, that could block implicit compilation.
247     */
248    public static final long AUXILIARY = 1L<<44;
249
250    /**
251     * Flag that marks that a symbol is not available in the current profile
252     */
253    public static final long NOT_IN_PROFILE = 1L<<45;
254
255    /**
256     * Flag that indicates that an override error has been detected by Check.
257     */
258    public static final long BAD_OVERRIDE = 1L<<45;
259
260    /**
261     * Flag that indicates a signature polymorphic method (292).
262     */
263    public static final long SIGNATURE_POLYMORPHIC = 1L<<46;
264
265    /**
266     * Flag that indicates that an inference variable is used in a 'throws' clause.
267     */
268    public static final long THROWS = 1L<<47;
269
270    /**
271     * Flag that marks potentially ambiguous overloads
272     */
273    public static final long POTENTIALLY_AMBIGUOUS = 1L<<48;
274
275    /**
276     * Flag that marks a synthetic method body for a lambda expression
277     */
278    public static final long LAMBDA_METHOD = 1L<<49;
279
280    /**
281     * Flag to control recursion in TransTypes
282     */
283    public static final long TYPE_TRANSLATED = 1L<<50;
284
285    /** Modifier masks.
286     */
287    public static final int
288        AccessFlags           = PUBLIC | PROTECTED | PRIVATE,
289        LocalClassFlags       = FINAL | ABSTRACT | STRICTFP | ENUM | SYNTHETIC,
290        MemberClassFlags      = LocalClassFlags | INTERFACE | AccessFlags,
291        ClassFlags            = LocalClassFlags | INTERFACE | PUBLIC | ANNOTATION,
292        InterfaceVarFlags     = FINAL | STATIC | PUBLIC,
293        VarFlags              = AccessFlags | FINAL | STATIC |
294                                VOLATILE | TRANSIENT | ENUM,
295        ConstructorFlags      = AccessFlags,
296        InterfaceMethodFlags  = ABSTRACT | PUBLIC,
297        MethodFlags           = AccessFlags | ABSTRACT | STATIC | NATIVE |
298                                SYNCHRONIZED | FINAL | STRICTFP;
299    public static final long
300        ExtendedStandardFlags       = (long)StandardFlags | DEFAULT,
301        ModifierFlags               = ((long)StandardFlags & ~INTERFACE) | DEFAULT,
302        InterfaceMethodMask         = ABSTRACT | PRIVATE | STATIC | PUBLIC | STRICTFP | DEFAULT,
303        AnnotationTypeElementMask   = ABSTRACT | PUBLIC,
304        LocalVarFlags               = FINAL | PARAMETER,
305        ReceiverParamFlags          = PARAMETER;
306
307
308    public static Set<Modifier> asModifierSet(long flags) {
309        Set<Modifier> modifiers = modifierSets.get(flags);
310        if (modifiers == null) {
311            modifiers = java.util.EnumSet.noneOf(Modifier.class);
312            if (0 != (flags & PUBLIC))    modifiers.add(Modifier.PUBLIC);
313            if (0 != (flags & PROTECTED)) modifiers.add(Modifier.PROTECTED);
314            if (0 != (flags & PRIVATE))   modifiers.add(Modifier.PRIVATE);
315            if (0 != (flags & ABSTRACT))  modifiers.add(Modifier.ABSTRACT);
316            if (0 != (flags & STATIC))    modifiers.add(Modifier.STATIC);
317            if (0 != (flags & FINAL))     modifiers.add(Modifier.FINAL);
318            if (0 != (flags & TRANSIENT)) modifiers.add(Modifier.TRANSIENT);
319            if (0 != (flags & VOLATILE))  modifiers.add(Modifier.VOLATILE);
320            if (0 != (flags & SYNCHRONIZED))
321                                          modifiers.add(Modifier.SYNCHRONIZED);
322            if (0 != (flags & NATIVE))    modifiers.add(Modifier.NATIVE);
323            if (0 != (flags & STRICTFP))  modifiers.add(Modifier.STRICTFP);
324            if (0 != (flags & DEFAULT))   modifiers.add(Modifier.DEFAULT);
325            modifiers = Collections.unmodifiableSet(modifiers);
326            modifierSets.put(flags, modifiers);
327        }
328        return modifiers;
329    }
330
331    // Cache of modifier sets.
332    private static final Map<Long, Set<Modifier>> modifierSets = new ConcurrentHashMap<>(64);
333
334    public static boolean isStatic(Symbol symbol) {
335        return (symbol.flags() & STATIC) != 0;
336    }
337
338    public static boolean isEnum(Symbol symbol) {
339        return (symbol.flags() & ENUM) != 0;
340    }
341
342    public static boolean isConstant(Symbol.VarSymbol symbol) {
343        return symbol.getConstValue() != null;
344    }
345
346
347    public enum Flag {
348        PUBLIC(Flags.PUBLIC),
349        PRIVATE(Flags.PRIVATE),
350        PROTECTED(Flags.PROTECTED),
351        STATIC(Flags.STATIC),
352        FINAL(Flags.FINAL),
353        SYNCHRONIZED(Flags.SYNCHRONIZED),
354        VOLATILE(Flags.VOLATILE),
355        TRANSIENT(Flags.TRANSIENT),
356        NATIVE(Flags.NATIVE),
357        INTERFACE(Flags.INTERFACE),
358        ABSTRACT(Flags.ABSTRACT),
359        DEFAULT(Flags.DEFAULT),
360        STRICTFP(Flags.STRICTFP),
361        BRIDGE(Flags.BRIDGE),
362        SYNTHETIC(Flags.SYNTHETIC),
363        ANNOTATION(Flags.ANNOTATION),
364        DEPRECATED(Flags.DEPRECATED),
365        HASINIT(Flags.HASINIT),
366        BLOCK(Flags.BLOCK),
367        ENUM(Flags.ENUM),
368        MANDATED(Flags.MANDATED),
369        IPROXY(Flags.IPROXY),
370        NOOUTERTHIS(Flags.NOOUTERTHIS),
371        EXISTS(Flags.EXISTS),
372        COMPOUND(Flags.COMPOUND),
373        CLASS_SEEN(Flags.CLASS_SEEN),
374        SOURCE_SEEN(Flags.SOURCE_SEEN),
375        LOCKED(Flags.LOCKED),
376        UNATTRIBUTED(Flags.UNATTRIBUTED),
377        ANONCONSTR(Flags.ANONCONSTR),
378        ACYCLIC(Flags.ACYCLIC),
379        PARAMETER(Flags.PARAMETER),
380        VARARGS(Flags.VARARGS),
381        ACYCLIC_ANN(Flags.ACYCLIC_ANN),
382        GENERATEDCONSTR(Flags.GENERATEDCONSTR),
383        HYPOTHETICAL(Flags.HYPOTHETICAL),
384        PROPRIETARY(Flags.PROPRIETARY),
385        UNION(Flags.UNION),
386        OVERRIDE_BRIDGE(Flags.OVERRIDE_BRIDGE),
387        EFFECTIVELY_FINAL(Flags.EFFECTIVELY_FINAL),
388        CLASH(Flags.CLASH),
389        AUXILIARY(Flags.AUXILIARY),
390        NOT_IN_PROFILE(Flags.NOT_IN_PROFILE),
391        BAD_OVERRIDE(Flags.BAD_OVERRIDE),
392        SIGNATURE_POLYMORPHIC(Flags.SIGNATURE_POLYMORPHIC),
393        THROWS(Flags.THROWS),
394        LAMBDA_METHOD(Flags.LAMBDA_METHOD),
395        TYPE_TRANSLATED(Flags.TYPE_TRANSLATED);
396
397        Flag(long flag) {
398            this.value = flag;
399            this.lowercaseName = StringUtils.toLowerCase(name());
400        }
401
402        @Override
403        public String toString() {
404            return lowercaseName;
405        }
406
407        final long value;
408        final String lowercaseName;
409    }
410
411}
412