1 /*
2 * Copyright (c) 2014, 2017, 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
23 * questions.
24 */
25
26 package java.lang;
27
28 import java.io.IOException;
29 import java.io.InputStream;
30 import java.lang.annotation.Annotation;
31 import java.lang.module.Configuration;
32 import java.lang.module.ModuleReference;
33 import java.lang.module.ModuleDescriptor;
34 import java.lang.module.ModuleDescriptor.Exports;
35 import java.lang.module.ModuleDescriptor.Opens;
36 import java.lang.module.ModuleDescriptor.Version;
37 import java.lang.module.ResolvedModule;
38 import java.lang.reflect.AnnotatedElement;
39 import java.net.URI;
40 import java.net.URL;
41 import java.security.AccessController;
42 import java.security.PrivilegedAction;
43 import java.util.Collections;
44 import java.util.HashMap;
45 import java.util.HashSet;
46 import java.util.List;
47 import java.util.Map;
48 import java.util.Objects;
49 import java.util.Optional;
50 import java.util.Set;
51 import java.util.concurrent.ConcurrentHashMap;
52 import java.util.function.Function;
53 import java.util.stream.Collectors;
54 import java.util.stream.Stream;
55
56 import jdk.internal.loader.BuiltinClassLoader;
57 import jdk.internal.loader.BootLoader;
58 import jdk.internal.misc.JavaLangAccess;
59 import jdk.internal.misc.SharedSecrets;
60 import jdk.internal.module.ServicesCatalog;
61 import jdk.internal.module.Resources;
62 import jdk.internal.org.objectweb.asm.AnnotationVisitor;
63 import jdk.internal.org.objectweb.asm.Attribute;
64 import jdk.internal.org.objectweb.asm.ClassReader;
65 import jdk.internal.org.objectweb.asm.ClassVisitor;
66 import jdk.internal.org.objectweb.asm.ClassWriter;
67 import jdk.internal.org.objectweb.asm.Opcodes;
68 import jdk.internal.reflect.CallerSensitive;
69 import jdk.internal.reflect.Reflection;
70 import sun.security.util.SecurityConstants;
71
72 /**
73 * Represents a run-time module, either {@link #isNamed() named} or unnamed.
74 *
75 * <p> Named modules have a {@link #getName() name} and are constructed by the
76 * Java Virtual Machine when a graph of modules is defined to the Java virtual
77 * machine to create a {@linkplain ModuleLayer module layer}. </p>
78 *
79 * <p> An unnamed module does not have a name. There is an unnamed module for
80 * each {@link ClassLoader ClassLoader}, obtained by invoking its {@link
81 * ClassLoader#getUnnamedModule() getUnnamedModule} method. All types that are
82 * not in a named module are members of their defining class loader's unnamed
83 * module. </p>
84 *
85 * <p> The package names that are parameters or returned by methods defined in
86 * this class are the fully-qualified names of the packages as defined in
87 * section 6.5.3 of <cite>The Java™ Language Specification</cite>, for
88 * example, {@code "java.lang"}. </p>
89 *
90 * <p> Unless otherwise specified, passing a {@code null} argument to a method
91 * in this class causes a {@link NullPointerException NullPointerException} to
92 * be thrown. </p>
93 *
94 * @since 9
95 * @spec JPMS
96 * @see Class#getModule()
97 */
98
99 public final class Module implements AnnotatedElement {
100
101 // the layer that contains this module, can be null
102 private final ModuleLayer layer;
103
104 // module name and loader, these fields are read by VM
105 private final String name;
106 private final ClassLoader loader;
107
108 // the module descriptor
109 private final ModuleDescriptor descriptor;
110
111
112 /**
113 * Creates a new named Module. The resulting Module will be defined to the
114 * VM but will not read any other modules, will not have any exports setup
115 * and will not be registered in the service catalog.
116 */
117 Module(ModuleLayer layer,
118 ClassLoader loader,
119 ModuleDescriptor descriptor,
120 URI uri)
121 {
122 this.layer = layer;
123 this.name = descriptor.name();
124 this.loader = loader;
125 this.descriptor = descriptor;
126
127 // define module to VM
128
129 boolean isOpen = descriptor.isOpen() || descriptor.isAutomatic();
130 Version version = descriptor.version().orElse(null);
131 String vs = Objects.toString(version, null);
132 String loc = Objects.toString(uri, null);
133 String[] packages = descriptor.packages().toArray(new String[0]);
134 defineModule0(this, isOpen, vs, loc, packages);
135 }
136
137
138 /**
139 * Create the unnamed Module for the given ClassLoader.
140 *
141 * @see ClassLoader#getUnnamedModule
142 */
143 Module(ClassLoader loader) {
144 this.layer = null;
145 this.name = null;
146 this.loader = loader;
147 this.descriptor = null;
148 }
149
150
151 /**
152 * Creates a named module but without defining the module to the VM.
153 *
154 * @apiNote This constructor is for VM white-box testing.
155 */
156 Module(ClassLoader loader, ModuleDescriptor descriptor) {
157 this.layer = null;
158 this.name = descriptor.name();
159 this.loader = loader;
160 this.descriptor = descriptor;
161 }
162
163
164
165 /**
166 * Returns {@code true} if this module is a named module.
167 *
168 * @return {@code true} if this is a named module
169 *
170 * @see ClassLoader#getUnnamedModule()
171 */
172 public boolean isNamed() {
173 return name != null;
174 }
175
176 /**
177 * Returns the module name or {@code null} if this module is an unnamed
178 * module.
179 *
180 * @return The module name
181 */
182 public String getName() {
183 return name;
184 }
185
186 /**
187 * Returns the {@code ClassLoader} for this module.
188 *
189 * <p> If there is a security manager then its {@code checkPermission}
190 * method if first called with a {@code RuntimePermission("getClassLoader")}
191 * permission to check that the caller is allowed to get access to the
192 * class loader. </p>
193 *
194 * @return The class loader for this module
195 *
196 * @throws SecurityException
197 * If denied by the security manager
198 */
199 public ClassLoader getClassLoader() {
200 SecurityManager sm = System.getSecurityManager();
201 if (sm != null) {
202 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
203 }
204 return loader;
205 }
206
207 /**
208 * Returns the module descriptor for this module or {@code null} if this
209 * module is an unnamed module.
210 *
211 * @return The module descriptor for this module
212 */
213 public ModuleDescriptor getDescriptor() {
214 return descriptor;
215 }
216
217 /**
218 * Returns the layer that contains this module or {@code null} if this
219 * module is not in a layer.
220 *
221 * A module layer contains named modules and therefore this method always
222 * returns {@code null} when invoked on an unnamed module.
223 *
224 * <p> <a href="reflect/Proxy.html#dynamicmodule">Dynamic modules</a> are
225 * named modules that are generated at runtime. A dynamic module may or may
226 * not be in a module layer. </p>
227 *
228 * @return The module layer that contains this module
229 *
230 * @see java.lang.reflect.Proxy
231 */
232 public ModuleLayer getLayer() {
233 if (isNamed()) {
234 ModuleLayer layer = this.layer;
235 if (layer != null)
236 return layer;
237
238 // special-case java.base as it is created before the boot layer
239 if (loader == null && name.equals("java.base")) {
240 return ModuleLayer.boot();
241 }
242 }
243 return null;
244 }
245
246
247 // --
248
249 // special Module to mean "all unnamed modules"
250 private static final Module ALL_UNNAMED_MODULE = new Module(null);
251
252 // special Module to mean "everyone"
253 private static final Module EVERYONE_MODULE = new Module(null);
254
255 // set contains EVERYONE_MODULE, used when a package is opened or
256 // exported unconditionally
257 private static final Set<Module> EVERYONE_SET = Set.of(EVERYONE_MODULE);
258
259
260 // -- readability --
261
262 // the modules that this module reads
263 private volatile Set<Module> reads;
264
265 // additional module (2nd key) that some module (1st key) reflectively reads
266 private static final WeakPairMap<Module, Module, Boolean> reflectivelyReads
267 = new WeakPairMap<>();
268
269
270 /**
271 * Indicates if this module reads the given module. This method returns
272 * {@code true} if invoked to test if this module reads itself. It also
273 * returns {@code true} if invoked on an unnamed module (as unnamed
274 * modules read all modules).
275 *
276 * @param other
277 * The other module
278 *
279 * @return {@code true} if this module reads {@code other}
280 *
281 * @see #addReads(Module)
282 */
283 public boolean canRead(Module other) {
284 Objects.requireNonNull(other);
285
286 // an unnamed module reads all modules
287 if (!this.isNamed())
288 return true;
289
290 // all modules read themselves
291 if (other == this)
292 return true;
293
294 // check if this module reads other
295 if (other.isNamed()) {
296 Set<Module> reads = this.reads; // volatile read
297 if (reads != null && reads.contains(other))
298 return true;
299 }
300
301 // check if this module reads the other module reflectively
302 if (reflectivelyReads.containsKeyPair(this, other))
303 return true;
304
305 // if other is an unnamed module then check if this module reads
306 // all unnamed modules
307 if (!other.isNamed()
308 && reflectivelyReads.containsKeyPair(this, ALL_UNNAMED_MODULE))
309 return true;
310
311 return false;
312 }
313
314 /**
315 * If the caller's module is this module then update this module to read
316 * the given module.
317 *
318 * This method is a no-op if {@code other} is this module (all modules read
319 * themselves), this module is an unnamed module (as unnamed modules read
320 * all modules), or this module already reads {@code other}.
321 *
322 * @implNote <em>Read edges</em> added by this method are <em>weak</em> and
323 * do not prevent {@code other} from being GC'ed when this module is
324 * strongly reachable.
325 *
326 * @param other
327 * The other module
328 *
329 * @return this module
330 *
331 * @throws IllegalCallerException
332 * If this is a named module and the caller's module is not this
333 * module
334 *
335 * @see #canRead
336 */
337 @CallerSensitive
338 public Module addReads(Module other) {
339 Objects.requireNonNull(other);
340 if (this.isNamed()) {
341 Module caller = getCallerModule(Reflection.getCallerClass());
342 if (caller != this) {
343 throw new IllegalCallerException(caller + " != " + this);
344 }
345 implAddReads(other, true);
346 }
347 return this;
348 }
349
350 /**
351 * Updates this module to read another module.
352 *
353 * @apiNote Used by the --add-reads command line option.
354 */
355 void implAddReads(Module other) {
356 implAddReads(other, true);
357 }
358
359 /**
360 * Updates this module to read all unnamed modules.
361 *
362 * @apiNote Used by the --add-reads command line option.
363 */
364 void implAddReadsAllUnnamed() {
365 implAddReads(Module.ALL_UNNAMED_MODULE, true);
366 }
367
368 /**
369 * Updates this module to read another module without notifying the VM.
370 *
371 * @apiNote This method is for VM white-box testing.
372 */
373 void implAddReadsNoSync(Module other) {
374 implAddReads(other, false);
375 }
376
377 /**
378 * Makes the given {@code Module} readable to this module.
379 *
380 * If {@code syncVM} is {@code true} then the VM is notified.
381 */
382 private void implAddReads(Module other, boolean syncVM) {
383 Objects.requireNonNull(other);
384 if (!canRead(other)) {
385 // update VM first, just in case it fails
386 if (syncVM) {
387 if (other == ALL_UNNAMED_MODULE) {
388 addReads0(this, null);
389 } else {
390 addReads0(this, other);
391 }
392 }
393
394 // add reflective read
395 reflectivelyReads.putIfAbsent(this, other, Boolean.TRUE);
396 }
397 }
398
399
400 // -- exported and open packages --
401
402 // the packages are open to other modules, can be null
403 // if the value contains EVERYONE_MODULE then the package is open to all
404 private volatile Map<String, Set<Module>> openPackages;
405
406 // the packages that are exported, can be null
407 // if the value contains EVERYONE_MODULE then the package is exported to all
408 private volatile Map<String, Set<Module>> exportedPackages;
409
410 // additional exports or opens added at run-time
411 // this module (1st key), other module (2nd key)
412 // (package name, open?) (value)
413 private static final WeakPairMap<Module, Module, Map<String, Boolean>>
414 reflectivelyExports = new WeakPairMap<>();
415
416
417 /**
418 * Returns {@code true} if this module exports the given package to at
419 * least the given module.
420 *
421 * <p> This method returns {@code true} if invoked to test if a package in
422 * this module is exported to itself. It always returns {@code true} when
423 * invoked on an unnamed module. A package that is {@link #isOpen open} to
424 * the given module is considered exported to that module at run-time and
425 * so this method returns {@code true} if the package is open to the given
426 * module. </p>
427 *
428 * <p> This method does not check if the given module reads this module. </p>
429 *
430 * @param pn
431 * The package name
432 * @param other
433 * The other module
434 *
435 * @return {@code true} if this module exports the package to at least the
436 * given module
437 *
438 * @see ModuleDescriptor#exports()
439 * @see #addExports(String,Module)
440 */
441 public boolean isExported(String pn, Module other) {
442 Objects.requireNonNull(pn);
443 Objects.requireNonNull(other);
444 return implIsExportedOrOpen(pn, other, /*open*/false);
445 }
446
447 /**
448 * Returns {@code true} if this module has <em>opened</em> a package to at
449 * least the given module.
450 *
451 * <p> This method returns {@code true} if invoked to test if a package in
452 * this module is open to itself. It returns {@code true} when invoked on an
453 * {@link ModuleDescriptor#isOpen open} module with a package in the module.
454 * It always returns {@code true} when invoked on an unnamed module. </p>
455 *
456 * <p> This method does not check if the given module reads this module. </p>
457 *
458 * @param pn
459 * The package name
460 * @param other
461 * The other module
462 *
463 * @return {@code true} if this module has <em>opened</em> the package
464 * to at least the given module
465 *
466 * @see ModuleDescriptor#opens()
467 * @see #addOpens(String,Module)
468 * @see AccessibleObject#setAccessible(boolean)
469 * @see java.lang.invoke.MethodHandles#privateLookupIn
470 */
471 public boolean isOpen(String pn, Module other) {
472 Objects.requireNonNull(pn);
473 Objects.requireNonNull(other);
474 return implIsExportedOrOpen(pn, other, /*open*/true);
475 }
476
477 /**
478 * Returns {@code true} if this module exports the given package
479 * unconditionally.
480 *
481 * <p> This method always returns {@code true} when invoked on an unnamed
482 * module. A package that is {@link #isOpen(String) opened} unconditionally
483 * is considered exported unconditionally at run-time and so this method
484 * returns {@code true} if the package is opened unconditionally. </p>
485 *
486 * <p> This method does not check if the given module reads this module. </p>
487 *
488 * @param pn
489 * The package name
490 *
491 * @return {@code true} if this module exports the package unconditionally
492 *
493 * @see ModuleDescriptor#exports()
494 */
495 public boolean isExported(String pn) {
496 Objects.requireNonNull(pn);
497 return implIsExportedOrOpen(pn, EVERYONE_MODULE, /*open*/false);
498 }
499
500 /**
501 * Returns {@code true} if this module has <em>opened</em> a package
502 * unconditionally.
503 *
504 * <p> This method always returns {@code true} when invoked on an unnamed
505 * module. Additionally, it always returns {@code true} when invoked on an
506 * {@link ModuleDescriptor#isOpen open} module with a package in the
507 * module. </p>
508 *
509 * <p> This method does not check if the given module reads this module. </p>
510 *
511 * @param pn
512 * The package name
513 *
514 * @return {@code true} if this module has <em>opened</em> the package
515 * unconditionally
516 *
517 * @see ModuleDescriptor#opens()
518 */
519 public boolean isOpen(String pn) {
520 Objects.requireNonNull(pn);
521 return implIsExportedOrOpen(pn, EVERYONE_MODULE, /*open*/true);
522 }
523
524
525 /**
526 * Returns {@code true} if this module exports or opens the given package
527 * to the given module. If the other module is {@code EVERYONE_MODULE} then
528 * this method tests if the package is exported or opened unconditionally.
529 */
530 private boolean implIsExportedOrOpen(String pn, Module other, boolean open) {
531 // all packages in unnamed modules are open
532 if (!isNamed())
533 return true;
534
535 // all packages are exported/open to self
536 if (other == this && containsPackage(pn))
537 return true;
538
539 // all packages in open and automatic modules are open
540 if (descriptor.isOpen() || descriptor.isAutomatic())
541 return containsPackage(pn);
542
543 // exported/opened via module declaration/descriptor
544 if (isStaticallyExportedOrOpen(pn, other, open))
545 return true;
546
547 // exported via addExports/addOpens
548 if (isReflectivelyExportedOrOpen(pn, other, open))
549 return true;
550
551 // not exported or open to other
552 return false;
553 }
554
555 /**
556 * Returns {@code true} if this module exports or opens a package to
557 * the given module via its module declaration.
558 */
559 private boolean isStaticallyExportedOrOpen(String pn, Module other, boolean open) {
560 // package is open to everyone or <other>
561 Map<String, Set<Module>> openPackages = this.openPackages;
562 if (openPackages != null) {
563 Set<Module> targets = openPackages.get(pn);
564 if (targets != null) {
565 if (targets.contains(EVERYONE_MODULE))
566 return true;
567 if (other != EVERYONE_MODULE && targets.contains(other))
568 return true;
569 }
570 }
571
572 if (!open) {
573 // package is exported to everyone or <other>
574 Map<String, Set<Module>> exportedPackages = this.exportedPackages;
575 if (exportedPackages != null) {
576 Set<Module> targets = exportedPackages.get(pn);
577 if (targets != null) {
578 if (targets.contains(EVERYONE_MODULE))
579 return true;
580 if (other != EVERYONE_MODULE && targets.contains(other))
581 return true;
582 }
583 }
584 }
585
586 return false;
587 }
588
589
590 /**
591 * Returns {@code true} if this module reflectively exports or opens given
592 * package package to the given module.
593 */
594 private boolean isReflectivelyExportedOrOpen(String pn, Module other, boolean open) {
595 // exported or open to all modules
596 Map<String, Boolean> exports = reflectivelyExports.get(this, EVERYONE_MODULE);
597 if (exports != null) {
598 Boolean b = exports.get(pn);
599 if (b != null) {
600 boolean isOpen = b.booleanValue();
601 if (!open || isOpen) return true;
602 }
603 }
604
605 if (other != EVERYONE_MODULE) {
606
607 // exported or open to other
608 exports = reflectivelyExports.get(this, other);
609 if (exports != null) {
610 Boolean b = exports.get(pn);
611 if (b != null) {
612 boolean isOpen = b.booleanValue();
613 if (!open || isOpen) return true;
614 }
615 }
616
617 // other is an unnamed module && exported or open to all unnamed
618 if (!other.isNamed()) {
619 exports = reflectivelyExports.get(this, ALL_UNNAMED_MODULE);
620 if (exports != null) {
621 Boolean b = exports.get(pn);
622 if (b != null) {
623 boolean isOpen = b.booleanValue();
624 if (!open || isOpen) return true;
625 }
626 }
627 }
628
629 }
630
631 return false;
632 }
633
634
635 /**
636 * If the caller's module is this module then update this module to export
637 * the given package to the given module.
638 *
639 * <p> This method has no effect if the package is already exported (or
640 * <em>open</em>) to the given module. </p>
641 *
642 * @apiNote As specified in section 5.4.3 of the <cite>The Java™
643 * Virtual Machine Specification </cite>, if an attempt to resolve a
644 * symbolic reference fails because of a linkage error, then subsequent
645 * attempts to resolve the reference always fail with the same error that
646 * was thrown as a result of the initial resolution attempt.
647 *
648 * @param pn
649 * The package name
650 * @param other
651 * The module
652 *
653 * @return this module
654 *
655 * @throws IllegalArgumentException
656 * If {@code pn} is {@code null}, or this is a named module and the
657 * package {@code pn} is not a package in this module
658 * @throws IllegalCallerException
659 * If this is a named module and the caller's module is not this
660 * module
661 *
662 * @jvms 5.4.3 Resolution
663 * @see #isExported(String,Module)
664 */
665 @CallerSensitive
666 public Module addExports(String pn, Module other) {
667 if (pn == null)
668 throw new IllegalArgumentException("package is null");
669 Objects.requireNonNull(other);
670
671 if (isNamed()) {
672 Module caller = getCallerModule(Reflection.getCallerClass());
673 if (caller != this) {
674 throw new IllegalCallerException(caller + " != " + this);
675 }
676 implAddExportsOrOpens(pn, other, /*open*/false, /*syncVM*/true);
677 }
678
679 return this;
680 }
681
682 /**
683 * If this module has <em>opened</em> a package to at least the caller
684 * module then update this module to open the package to the given module.
685 * Opening a package with this method allows all types in the package,
686 * and all their members, not just public types and their public members,
687 * to be reflected on by the given module when using APIs that support
688 * private access or a way to bypass or suppress default Java language
689 * access control checks.
690 *
691 * <p> This method has no effect if the package is already <em>open</em>
692 * to the given module. </p>
693 *
694 * @param pn
695 * The package name
696 * @param other
697 * The module
698 *
699 * @return this module
700 *
701 * @throws IllegalArgumentException
702 * If {@code pn} is {@code null}, or this is a named module and the
703 * package {@code pn} is not a package in this module
704 * @throws IllegalCallerException
705 * If this is a named module and this module has not opened the
706 * package to at least the caller's module
707 *
708 * @see #isOpen(String,Module)
709 * @see AccessibleObject#setAccessible(boolean)
710 * @see java.lang.invoke.MethodHandles#privateLookupIn
711 */
712 @CallerSensitive
713 public Module addOpens(String pn, Module other) {
714 if (pn == null)
715 throw new IllegalArgumentException("package is null");
716 Objects.requireNonNull(other);
717
718 if (isNamed()) {
719 Module caller = getCallerModule(Reflection.getCallerClass());
720 if (caller != this && (caller == null || !isOpen(pn, caller)))
721 throw new IllegalCallerException(pn + " is not open to " + caller);
722 implAddExportsOrOpens(pn, other, /*open*/true, /*syncVM*/true);
723 }
724
725 return this;
726 }
727
728
729 /**
730 * Updates this module to export a package unconditionally.
731 *
732 * @apiNote This method is for JDK tests only.
733 */
734 void implAddExports(String pn) {
735 implAddExportsOrOpens(pn, Module.EVERYONE_MODULE, false, true);
736 }
737
738 /**
739 * Updates this module to export a package to another module.
740 *
741 * @apiNote Used by Instrumentation::redefineModule and --add-exports
742 */
743 void implAddExports(String pn, Module other) {
744 implAddExportsOrOpens(pn, other, false, true);
745 }
746
747 /**
748 * Updates this module to export a package to all unnamed modules.
749 *
750 * @apiNote Used by the --add-exports command line option.
751 */
752 void implAddExportsToAllUnnamed(String pn) {
753 implAddExportsOrOpens(pn, Module.ALL_UNNAMED_MODULE, false, true);
754 }
755
756 /**
757 * Updates this export to export a package unconditionally without
758 * notifying the VM.
759 *
760 * @apiNote This method is for VM white-box testing.
761 */
762 void implAddExportsNoSync(String pn) {
763 implAddExportsOrOpens(pn.replace('/', '.'), Module.EVERYONE_MODULE, false, false);
764 }
765
766 /**
767 * Updates a module to export a package to another module without
768 * notifying the VM.
769 *
770 * @apiNote This method is for VM white-box testing.
771 */
772 void implAddExportsNoSync(String pn, Module other) {
773 implAddExportsOrOpens(pn.replace('/', '.'), other, false, false);
774 }
775
776 /**
777 * Updates this module to open a package unconditionally.
778 *
779 * @apiNote This method is for JDK tests only.
780 */
781 void implAddOpens(String pn) {
782 implAddExportsOrOpens(pn, Module.EVERYONE_MODULE, true, true);
783 }
784
785 /**
786 * Updates this module to open a package to another module.
787 *
788 * @apiNote Used by Instrumentation::redefineModule and --add-opens
789 */
790 void implAddOpens(String pn, Module other) {
791 implAddExportsOrOpens(pn, other, true, true);
792 }
793
794 /**
795 * Updates this module to export a package to all unnamed modules.
796 *
797 * @apiNote Used by the --add-opens command line option.
798 */
799 void implAddOpensToAllUnnamed(String pn) {
800 implAddExportsOrOpens(pn, Module.ALL_UNNAMED_MODULE, true, true);
801 }
802
803
804 /**
805 * Updates a module to export or open a module to another module.
806 *
807 * If {@code syncVM} is {@code true} then the VM is notified.
808 */
809 private void implAddExportsOrOpens(String pn,
810 Module other,
811 boolean open,
812 boolean syncVM) {
813 Objects.requireNonNull(other);
814 Objects.requireNonNull(pn);
815
816 // all packages are open in unnamed, open, and automatic modules
817 if (!isNamed() || descriptor.isOpen() || descriptor.isAutomatic())
818 return;
819
820 // nothing to do if already exported/open to other
821 if (implIsExportedOrOpen(pn, other, open))
822 return;
823
824 // can only export a package in the module
825 if (!containsPackage(pn)) {
826 throw new IllegalArgumentException("package " + pn
827 + " not in contents");
828 }
829
830 // update VM first, just in case it fails
831 if (syncVM) {
832 if (other == EVERYONE_MODULE) {
833 addExportsToAll0(this, pn);
834 } else if (other == ALL_UNNAMED_MODULE) {
835 addExportsToAllUnnamed0(this, pn);
836 } else {
837 addExports0(this, pn, other);
838 }
839 }
840
841 // add package name to reflectivelyExports if absent
842 Map<String, Boolean> map = reflectivelyExports
843 .computeIfAbsent(this, other,
844 (m1, m2) -> new ConcurrentHashMap<>());
845
846 if (open) {
847 map.put(pn, Boolean.TRUE); // may need to promote from FALSE to TRUE
848 } else {
849 map.putIfAbsent(pn, Boolean.FALSE);
850 }
851 }
852
853
854 // -- services --
855
856 // additional service type (2nd key) that some module (1st key) uses
857 private static final WeakPairMap<Module, Class<?>, Boolean> reflectivelyUses
858 = new WeakPairMap<>();
859
860 /**
861 * If the caller's module is this module then update this module to add a
862 * service dependence on the given service type. This method is intended
863 * for use by frameworks that invoke {@link java.util.ServiceLoader
864 * ServiceLoader} on behalf of other modules or where the framework is
865 * passed a reference to the service type by other code. This method is
866 * a no-op when invoked on an unnamed module or an automatic module.
867 *
868 * <p> This method does not cause {@link Configuration#resolveAndBind
869 * resolveAndBind} to be re-run. </p>
870 *
871 * @param service
872 * The service type
873 *
874 * @return this module
875 *
876 * @throws IllegalCallerException
877 * If this is a named module and the caller's module is not this
878 * module
879 *
880 * @see #canUse(Class)
881 * @see ModuleDescriptor#uses()
882 */
883 @CallerSensitive
884 public Module addUses(Class<?> service) {
885 Objects.requireNonNull(service);
886
887 if (isNamed() && !descriptor.isAutomatic()) {
888 Module caller = getCallerModule(Reflection.getCallerClass());
889 if (caller != this) {
890 throw new IllegalCallerException(caller + " != " + this);
891 }
892 implAddUses(service);
893 }
894
895 return this;
896 }
897
898 /**
899 * Update this module to add a service dependence on the given service
900 * type.
901 */
902 void implAddUses(Class<?> service) {
903 if (!canUse(service)) {
904 reflectivelyUses.putIfAbsent(this, service, Boolean.TRUE);
905 }
906 }
907
908
909 /**
910 * Indicates if this module has a service dependence on the given service
911 * type. This method always returns {@code true} when invoked on an unnamed
912 * module or an automatic module.
913 *
914 * @param service
915 * The service type
916 *
917 * @return {@code true} if this module uses service type {@code st}
918 *
919 * @see #addUses(Class)
920 */
921 public boolean canUse(Class<?> service) {
922 Objects.requireNonNull(service);
923
924 if (!isNamed())
925 return true;
926
927 if (descriptor.isAutomatic())
928 return true;
929
930 // uses was declared
931 if (descriptor.uses().contains(service.getName()))
932 return true;
933
934 // uses added via addUses
935 return reflectivelyUses.containsKeyPair(this, service);
936 }
937
938
939
940 // -- packages --
941
942 // Additional packages that are added to the module at run-time.
943 private volatile Map<String, Boolean> extraPackages;
944
945 private boolean containsPackage(String pn) {
946 if (descriptor.packages().contains(pn))
947 return true;
948 Map<String, Boolean> extraPackages = this.extraPackages;
949 if (extraPackages != null && extraPackages.containsKey(pn))
950 return true;
951 return false;
952 }
953
954
955 /**
956 * Returns the set of package names for the packages in this module.
957 *
958 * <p> For named modules, the returned set contains an element for each
959 * package in the module. </p>
960 *
961 * <p> For unnamed modules, this method is the equivalent to invoking the
962 * {@link ClassLoader#getDefinedPackages() getDefinedPackages} method of
963 * this module's class loader and returning the set of package names. </p>
964 *
965 * @return the set of the package names of the packages in this module
966 */
967 public Set<String> getPackages() {
968 if (isNamed()) {
969
970 Set<String> packages = descriptor.packages();
971 Map<String, Boolean> extraPackages = this.extraPackages;
972 if (extraPackages == null) {
973 return packages;
974 } else {
975 return Stream.concat(packages.stream(),
976 extraPackages.keySet().stream())
977 .collect(Collectors.toSet());
978 }
979
980 } else {
981 // unnamed module
982 Stream<Package> packages;
983 if (loader == null) {
984 packages = BootLoader.packages();
985 } else {
986 packages = SharedSecrets.getJavaLangAccess().packages(loader);
987 }
988 return packages.map(Package::getName).collect(Collectors.toSet());
989 }
990 }
991
992 /**
993 * Add a package to this module without notifying the VM.
994 *
995 * @apiNote This method is VM white-box testing.
996 */
997 void implAddPackageNoSync(String pn) {
998 implAddPackage(pn.replace('/', '.'), false);
999 }
1000
1001 /**
1002 * Add a package to this module.
1003 *
1004 * If {@code syncVM} is {@code true} then the VM is notified. This method is
1005 * a no-op if this is an unnamed module or the module already contains the
1006 * package.
1007 *
1008 * @throws IllegalArgumentException if the package name is not legal
1009 * @throws IllegalStateException if the package is defined to another module
1010 */
1011 private void implAddPackage(String pn, boolean syncVM) {
1012 // no-op if unnamed module
1013 if (!isNamed())
1014 return;
1015
1016 // no-op if module contains the package
1017 if (containsPackage(pn))
1018 return;
1019
1020 // check package name is legal for named modules
1021 if (pn.isEmpty())
1022 throw new IllegalArgumentException("Cannot add <unnamed> package");
1023 for (int i=0; i<pn.length(); i++) {
1024 char c = pn.charAt(i);
1025 if (c == '/' || c == ';' || c == '[') {
1026 throw new IllegalArgumentException("Illegal character: " + c);
1027 }
1028 }
1029
1030 // create extraPackages if needed
1031 Map<String, Boolean> extraPackages = this.extraPackages;
1032 if (extraPackages == null) {
1033 synchronized (this) {
1034 extraPackages = this.extraPackages;
1035 if (extraPackages == null)
1036 this.extraPackages = extraPackages = new ConcurrentHashMap<>();
1037 }
1038 }
1039
1040 // update VM first in case it fails. This is a no-op if another thread
1041 // beats us to add the package first
1042 if (syncVM) {
1043 // throws IllegalStateException if defined to another module
1044 addPackage0(this, pn);
1045 }
1046 extraPackages.putIfAbsent(pn, Boolean.TRUE);
1047 }
1048
1049
1050 // -- creating Module objects --
1051
1052 /**
1053 * Defines all module in a configuration to the runtime.
1054 *
1055 * @return a map of module name to runtime {@code Module}
1056 *
1057 * @throws IllegalArgumentException
1058 * If defining any of the modules to the VM fails
1059 */
1060 static Map<String, Module> defineModules(Configuration cf,
1061 Function<String, ClassLoader> clf,
1062 ModuleLayer layer)
1063 {
1064 Map<String, Module> nameToModule = new HashMap<>();
1065 Map<String, ClassLoader> moduleToLoader = new HashMap<>();
1066
1067 boolean isBootLayer = (ModuleLayer.boot() == null);
1068 Set<ClassLoader> loaders = new HashSet<>();
1069
1070 // map each module to a class loader
1071 for (ResolvedModule resolvedModule : cf.modules()) {
1072 String name = resolvedModule.name();
1073 ClassLoader loader = clf.apply(name);
1074 if (loader != null) {
1075 moduleToLoader.put(name, loader);
1076 loaders.add(loader);
1077 } else if (!isBootLayer) {
1078 throw new IllegalArgumentException("loader can't be 'null'");
1079 }
1080 }
1081
1082 // define each module in the configuration to the VM
1083 for (ResolvedModule resolvedModule : cf.modules()) {
1084 ModuleReference mref = resolvedModule.reference();
1085 ModuleDescriptor descriptor = mref.descriptor();
1086 String name = descriptor.name();
1087 URI uri = mref.location().orElse(null);
1088 ClassLoader loader = moduleToLoader.get(resolvedModule.name());
1089 Module m;
1090 if (loader == null && isBootLayer && name.equals("java.base")) {
1091 // java.base is already defined to the VM
1092 m = Object.class.getModule();
1093 } else {
1094 m = new Module(layer, loader, descriptor, uri);
1095 }
1096 nameToModule.put(name, m);
1097 moduleToLoader.put(name, loader);
1098 }
1099
1100 // setup readability and exports
1101 for (ResolvedModule resolvedModule : cf.modules()) {
1102 ModuleReference mref = resolvedModule.reference();
1103 ModuleDescriptor descriptor = mref.descriptor();
1104
1105 String mn = descriptor.name();
1106 Module m = nameToModule.get(mn);
1107 assert m != null;
1108
1109 // reads
1110 Set<Module> reads = new HashSet<>();
1111
1112 // name -> source Module when in parent layer
1113 Map<String, Module> nameToSource = Collections.emptyMap();
1114
1115 for (ResolvedModule other : resolvedModule.reads()) {
1116 Module m2 = null;
1117 if (other.configuration() == cf) {
1118 // this configuration
1119 m2 = nameToModule.get(other.name());
1120 assert m2 != null;
1121 } else {
1122 // parent layer
1123 for (ModuleLayer parent: layer.parents()) {
1124 m2 = findModule(parent, other);
1125 if (m2 != null)
1126 break;
1127 }
1128 assert m2 != null;
1129 if (nameToSource.isEmpty())
1130 nameToSource = new HashMap<>();
1131 nameToSource.put(other.name(), m2);
1132 }
1133 reads.add(m2);
1134
1135 // update VM view
1136 addReads0(m, m2);
1137 }
1138 m.reads = reads;
1139
1140 // automatic modules read all unnamed modules
1141 if (descriptor.isAutomatic()) {
1142 m.implAddReads(ALL_UNNAMED_MODULE, true);
1143 }
1144
1145 // exports and opens
1146 initExportsAndOpens(m, nameToSource, nameToModule, layer.parents());
1147 }
1148
1149 // register the modules in the boot layer
1150 if (isBootLayer) {
1151 for (ResolvedModule resolvedModule : cf.modules()) {
1152 ModuleReference mref = resolvedModule.reference();
1153 ModuleDescriptor descriptor = mref.descriptor();
1154 if (!descriptor.provides().isEmpty()) {
1155 String name = descriptor.name();
1156 Module m = nameToModule.get(name);
1157 ClassLoader loader = moduleToLoader.get(name);
1158 ServicesCatalog catalog;
1159 if (loader == null) {
1160 catalog = BootLoader.getServicesCatalog();
1161 } else {
1162 catalog = ServicesCatalog.getServicesCatalog(loader);
1163 }
1164 catalog.register(m);
1165 }
1166 }
1167 }
1168
1169 // record that there is a layer with modules defined to the class loader
1170 for (ClassLoader loader : loaders) {
1171 layer.bindToLoader(loader);
1172 }
1173
1174 return nameToModule;
1175 }
1176
1177
1178 /**
1179 * Find the runtime Module corresponding to the given ResolvedModule
1180 * in the given parent layer (or its parents).
1181 */
1182 private static Module findModule(ModuleLayer parent,
1183 ResolvedModule resolvedModule) {
1184 Configuration cf = resolvedModule.configuration();
1185 String dn = resolvedModule.name();
1186 return parent.layers()
1187 .filter(l -> l.configuration() == cf)
1188 .findAny()
1189 .map(layer -> {
1190 Optional<Module> om = layer.findModule(dn);
1191 assert om.isPresent() : dn + " not found in layer";
1192 Module m = om.get();
1193 assert m.getLayer() == layer : m + " not in expected layer";
1194 return m;
1195 })
1196 .orElse(null);
1197 }
1198
1199
1200 /**
1201 * Initialize the maps of exported and open packages for module m.
1202 */
1203 private static void initExportsAndOpens(Module m,
1204 Map<String, Module> nameToSource,
1205 Map<String, Module> nameToModule,
1206 List<ModuleLayer> parents) {
1207 // The VM special cases open and automatic modules so don't need to
1208 // export their packages
1209 ModuleDescriptor descriptor = m.getDescriptor();
1210 if (descriptor.isOpen() || descriptor.isAutomatic()) {
1211 return;
1212 }
1213
1214 Map<String, Set<Module>> openPackages = new HashMap<>();
1215 Map<String, Set<Module>> exportedPackages = new HashMap<>();
1216
1217 // process the open packages first
1218 for (Opens opens : descriptor.opens()) {
1219 String source = opens.source();
1220
1221 if (opens.isQualified()) {
1222 // qualified opens
1223 Set<Module> targets = new HashSet<>();
1224 for (String target : opens.targets()) {
1225 Module m2 = findModule(target, nameToSource, nameToModule, parents);
1226 if (m2 != null) {
1227 addExports0(m, source, m2);
1228 targets.add(m2);
1229 }
1230 }
1231 if (!targets.isEmpty()) {
1232 openPackages.put(source, targets);
1233 }
1234 } else {
1235 // unqualified opens
1236 addExportsToAll0(m, source);
1237 openPackages.put(source, EVERYONE_SET);
1238 }
1239 }
1240
1241 // next the exports, skipping exports when the package is open
1242 for (Exports exports : descriptor.exports()) {
1243 String source = exports.source();
1244
1245 // skip export if package is already open to everyone
1246 Set<Module> openToTargets = openPackages.get(source);
1247 if (openToTargets != null && openToTargets.contains(EVERYONE_MODULE))
1248 continue;
1249
1250 if (exports.isQualified()) {
1251 // qualified exports
1252 Set<Module> targets = new HashSet<>();
1253 for (String target : exports.targets()) {
1254 Module m2 = findModule(target, nameToSource, nameToModule, parents);
1255 if (m2 != null) {
1256 // skip qualified export if already open to m2
1257 if (openToTargets == null || !openToTargets.contains(m2)) {
1258 addExports0(m, source, m2);
1259 targets.add(m2);
1260 }
1261 }
1262 }
1263 if (!targets.isEmpty()) {
1264 exportedPackages.put(source, targets);
1265 }
1266
1267 } else {
1268 // unqualified exports
1269 addExportsToAll0(m, source);
1270 exportedPackages.put(source, EVERYONE_SET);
1271 }
1272 }
1273
1274 if (!openPackages.isEmpty())
1275 m.openPackages = openPackages;
1276 if (!exportedPackages.isEmpty())
1277 m.exportedPackages = exportedPackages;
1278 }
1279
1280 /**
1281 * Find the runtime Module with the given name. The module name is the
1282 * name of a target module in a qualified exports or opens directive.
1283 *
1284 * @param target The target module to find
1285 * @param nameToSource The modules in parent layers that are read
1286 * @param nameToModule The modules in the layer under construction
1287 * @param parents The parent layers
1288 */
1289 private static Module findModule(String target,
1290 Map<String, Module> nameToSource,
1291 Map<String, Module> nameToModule,
1292 List<ModuleLayer> parents) {
1293 Module m = nameToSource.get(target);
1294 if (m == null) {
1295 m = nameToModule.get(target);
1296 if (m == null) {
1297 for (ModuleLayer parent : parents) {
1298 m = parent.findModule(target).orElse(null);
1299 if (m != null) break;
1300 }
1301 }
1302 }
1303 return m;
1304 }
1305
1306
1307 // -- annotations --
1308
1309 /**
1310 * {@inheritDoc}
1311 * This method returns {@code null} when invoked on an unnamed module.
1312 */
1313 @Override
1314 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
1315 return moduleInfoClass().getDeclaredAnnotation(annotationClass);
1316 }
1317
1318 /**
1319 * {@inheritDoc}
1320 * This method returns an empty array when invoked on an unnamed module.
1321 */
1322 @Override
1323 public Annotation[] getAnnotations() {
1324 return moduleInfoClass().getAnnotations();
1325 }
1326
1327 /**
1328 * {@inheritDoc}
1329 * This method returns an empty array when invoked on an unnamed module.
1330 */
1331 @Override
1332 public Annotation[] getDeclaredAnnotations() {
1333 return moduleInfoClass().getDeclaredAnnotations();
1334 }
1335
1336 // cached class file with annotations
1337 private volatile Class<?> moduleInfoClass;
1338
1339 private Class<?> moduleInfoClass() {
1340 Class<?> clazz = this.moduleInfoClass;
1341 if (clazz != null)
1342 return clazz;
1343
1344 synchronized (this) {
1345 clazz = this.moduleInfoClass;
1346 if (clazz == null) {
1347 if (isNamed()) {
1348 PrivilegedAction<Class<?>> pa = this::loadModuleInfoClass;
1349 clazz = AccessController.doPrivileged(pa);
1350 }
1351 if (clazz == null) {
1352 class DummyModuleInfo { }
1353 clazz = DummyModuleInfo.class;
1354 }
1355 this.moduleInfoClass = clazz;
1356 }
1357 return clazz;
1358 }
1359 }
1360
1361 private Class<?> loadModuleInfoClass() {
1362 Class<?> clazz = null;
1363 try (InputStream in = getResourceAsStream("module-info.class")) {
1364 if (in != null)
1365 clazz = loadModuleInfoClass(in);
1366 } catch (Exception ignore) { }
1367 return clazz;
1368 }
1369
1370 /**
1371 * Loads module-info.class as a package-private interface in a class loader
1372 * that is a child of this module's class loader.
1373 */
1374 private Class<?> loadModuleInfoClass(InputStream in) throws IOException {
1375 final String MODULE_INFO = "module-info";
1376
1377 ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS
1378 + ClassWriter.COMPUTE_FRAMES);
1379
1380 ClassVisitor cv = new ClassVisitor(Opcodes.ASM5, cw) {
1381 @Override
1382 public void visit(int version,
1383 int access,
1384 String name,
1385 String signature,
1386 String superName,
1387 String[] interfaces) {
1388 cw.visit(version,
1389 Opcodes.ACC_INTERFACE
1390 + Opcodes.ACC_ABSTRACT
1391 + Opcodes.ACC_SYNTHETIC,
1392 MODULE_INFO,
1393 null,
1394 "java/lang/Object",
1395 null);
1396 }
1397 @Override
1398 public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
1399 // keep annotations
1400 return super.visitAnnotation(desc, visible);
1401 }
1402 @Override
1403 public void visitAttribute(Attribute attr) {
1404 // drop non-annotation attributes
1405 }
1406 };
1407
1408 ClassReader cr = new ClassReader(in);
1409 cr.accept(cv, 0);
1410 byte[] bytes = cw.toByteArray();
1411
1412 ClassLoader cl = new ClassLoader(loader) {
1413 @Override
1414 protected Class<?> findClass(String cn)throws ClassNotFoundException {
1415 if (cn.equals(MODULE_INFO)) {
1416 return super.defineClass(cn, bytes, 0, bytes.length);
1417 } else {
1418 throw new ClassNotFoundException(cn);
1419 }
1420 }
1421 };
1422
1423 try {
1424 return cl.loadClass(MODULE_INFO);
1425 } catch (ClassNotFoundException e) {
1426 throw new InternalError(e);
1427 }
1428 }
1429
1430
1431 // -- misc --
1432
1433
1434 /**
1435 * Returns an input stream for reading a resource in this module.
1436 * The {@code name} parameter is a {@code '/'}-separated path name that
1437 * identifies the resource. As with {@link Class#getResourceAsStream
1438 * Class.getResourceAsStream}, this method delegates to the module's class
1439 * loader {@link ClassLoader#findResource(String,String)
1440 * findResource(String,String)} method, invoking it with the module name
1441 * (or {@code null} when the module is unnamed) and the name of the
1442 * resource. If the resource name has a leading slash then it is dropped
1443 * before delegation.
1444 *
1445 * <p> A resource in a named module may be <em>encapsulated</em> so that
1446 * it cannot be located by code in other modules. Whether a resource can be
1447 * located or not is determined as follows: </p>
1448 *
1449 * <ul>
1450 * <li> If the resource name ends with "{@code .class}" then it is not
1451 * encapsulated. </li>
1452 *
1453 * <li> A <em>package name</em> is derived from the resource name. If
1454 * the package name is a {@link #getPackages() package} in the module
1455 * then the resource can only be located by the caller of this method
1456 * when the package is {@link #isOpen(String,Module) open} to at least
1457 * the caller's module. If the resource is not in a package in the module
1458 * then the resource is not encapsulated. </li>
1459 * </ul>
1460 *
1461 * <p> In the above, the <em>package name</em> for a resource is derived
1462 * from the subsequence of characters that precedes the last {@code '/'} in
1463 * the name and then replacing each {@code '/'} character in the subsequence
1464 * with {@code '.'}. A leading slash is ignored when deriving the package
1465 * name. As an example, the package name derived for a resource named
1466 * "{@code a/b/c/foo.properties}" is "{@code a.b.c}". A resource name
1467 * with the name "{@code META-INF/MANIFEST.MF}" is never encapsulated
1468 * because "{@code META-INF}" is not a legal package name. </p>
1469 *
1470 * <p> This method returns {@code null} if the resource is not in this
1471 * module, the resource is encapsulated and cannot be located by the caller,
1472 * or access to the resource is denied by the security manager. </p>
1473 *
1474 * @param name
1475 * The resource name
1476 *
1477 * @return An input stream for reading the resource or {@code null}
1478 *
1479 * @throws IOException
1480 * If an I/O error occurs
1481 *
1482 * @see Class#getResourceAsStream(String)
1483 */
1484 @CallerSensitive
1485 public InputStream getResourceAsStream(String name) throws IOException {
1486 if (name.startsWith("/")) {
1487 name = name.substring(1);
1488 }
1489
1490 if (isNamed() && Resources.canEncapsulate(name)) {
1491 Module caller = getCallerModule(Reflection.getCallerClass());
1492 if (caller != this && caller != Object.class.getModule()) {
1493 String pn = Resources.toPackageName(name);
1494 if (getPackages().contains(pn)) {
1495 if (caller == null && !isOpen(pn)) {
1496 // no caller, package not open
1497 return null;
1498 }
1499 if (!isOpen(pn, caller)) {
1500 // package not open to caller
1501 return null;
1502 }
1503 }
1504 }
1505 }
1506
1507 String mn = this.name;
1508
1509 // special-case built-in class loaders to avoid URL connection
1510 if (loader == null) {
1511 return BootLoader.findResourceAsStream(mn, name);
1512 } else if (loader instanceof BuiltinClassLoader) {
1513 return ((BuiltinClassLoader) loader).findResourceAsStream(mn, name);
1514 }
1515
1516 // locate resource in module
1517 JavaLangAccess jla = SharedSecrets.getJavaLangAccess();
1518 URL url = jla.findResource(loader, mn, name);
1519 if (url != null) {
1520 try {
1521 return url.openStream();
1522 } catch (SecurityException e) { }
1523 }
1524
1525 return null;
1526 }
1527
1528 /**
1529 * Returns the string representation of this module. For a named module,
1530 * the representation is the string {@code "module"}, followed by a space,
1531 * and then the module name. For an unnamed module, the representation is
1532 * the string {@code "unnamed module"}, followed by a space, and then an
1533 * implementation specific string that identifies the unnamed module.
1534 *
1535 * @return The string representation of this module
1536 */
1537 @Override
1538 public String toString() {
1539 if (isNamed()) {
1540 return "module " + name;
1541 } else {
1542 String id = Integer.toHexString(System.identityHashCode(this));
1543 return "unnamed module @" + id;
1544 }
1545 }
1546
1547 /**
1548 * Returns the module that a given caller class is a member of. Returns
1549 * {@code null} if the caller is {@code null}.
1550 */
1551 private Module getCallerModule(Class<?> caller) {
1552 return (caller != null) ? caller.getModule() : null;
1553 }
1554
1555
1556 // -- native methods --
1557
1558 // JVM_DefineModule
1559 private static native void defineModule0(Module module,
1560 boolean isOpen,
1561 String version,
1562 String location,
1563 String[] pns);
1564
1565 // JVM_AddReadsModule
1566 private static native void addReads0(Module from, Module to);
1567
1568 // JVM_AddModuleExports
1569 private static native void addExports0(Module from, String pn, Module to);
1570
1571 // JVM_AddModuleExportsToAll
1572 private static native void addExportsToAll0(Module from, String pn);
1573
1574 // JVM_AddModuleExportsToAllUnnamed
1575 private static native void addExportsToAllUnnamed0(Module from, String pn);
1576
1577 // JVM_AddModulePackage
1578 private static native void addPackage0(Module m, String pn);
1579 }