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.Iterator;
47 import java.util.List;
48 import java.util.Map;
49 import java.util.Objects;
50 import java.util.Optional;
51 import java.util.Set;
52 import java.util.concurrent.ConcurrentHashMap;
53 import java.util.function.Function;
54 import java.util.stream.Collectors;
55 import java.util.stream.Stream;
56
57 import jdk.internal.loader.BuiltinClassLoader;
58 import jdk.internal.loader.BootLoader;
59 import jdk.internal.loader.ClassLoaders;
60 import jdk.internal.module.IllegalAccessLogger;
61 import jdk.internal.module.ModuleLoaderMap;
62 import jdk.internal.module.ServicesCatalog;
63 import jdk.internal.module.Resources;
64 import jdk.internal.org.objectweb.asm.AnnotationVisitor;
65 import jdk.internal.org.objectweb.asm.Attribute;
66 import jdk.internal.org.objectweb.asm.ClassReader;
67 import jdk.internal.org.objectweb.asm.ClassVisitor;
68 import jdk.internal.org.objectweb.asm.ClassWriter;
69 import jdk.internal.org.objectweb.asm.ModuleVisitor;
70 import jdk.internal.org.objectweb.asm.Opcodes;
71 import jdk.internal.reflect.CallerSensitive;
72 import jdk.internal.reflect.Reflection;
73 import sun.security.util.SecurityConstants;
74
75 /**
76 * Represents a run-time module, either {@link #isNamed() named} or unnamed.
77 *
78 * <p> Named modules have a {@link #getName() name} and are constructed by the
79 * Java Virtual Machine when a graph of modules is defined to the Java virtual
80 * machine to create a {@linkplain ModuleLayer module layer}. </p>
81 *
82 * <p> An unnamed module does not have a name. There is an unnamed module for
83 * each {@link ClassLoader ClassLoader}, obtained by invoking its {@link
84 * ClassLoader#getUnnamedModule() getUnnamedModule} method. All types that are
85 * not in a named module are members of their defining class loader's unnamed
86 * module. </p>
87 *
88 * <p> The package names that are parameters or returned by methods defined in
89 * this class are the fully-qualified names of the packages as defined in
90 * section 6.5.3 of <cite>The Java™ Language Specification</cite>, for
91 * example, {@code "java.lang"}. </p>
92 *
93 * <p> Unless otherwise specified, passing a {@code null} argument to a method
94 * in this class causes a {@link NullPointerException NullPointerException} to
95 * be thrown. </p>
96 *
97 * @since 9
98 * @spec JPMS
99 * @see Class#getModule()
100 */
101
102 public final class Module implements AnnotatedElement {
103
104 // the layer that contains this module, can be null
105 private final ModuleLayer layer;
106
107 // module name and loader, these fields are read by VM
108 private final String name;
109 private final ClassLoader loader;
110
111 // the module descriptor
112 private final ModuleDescriptor descriptor;
113
114
115 /**
116 * Creates a new named Module. The resulting Module will be defined to the
117 * VM but will not read any other modules, will not have any exports setup
118 * and will not be registered in the service catalog.
119 */
120 Module(ModuleLayer layer,
121 ClassLoader loader,
122 ModuleDescriptor descriptor,
123 URI uri)
124 {
125 this.layer = layer;
126 this.name = descriptor.name();
127 this.loader = loader;
128 this.descriptor = descriptor;
129
130 // define module to VM
131
132 boolean isOpen = descriptor.isOpen() || descriptor.isAutomatic();
133 Version version = descriptor.version().orElse(null);
134 String vs = Objects.toString(version, null);
135 String loc = Objects.toString(uri, null);
136 String[] packages = descriptor.packages().toArray(new String[0]);
137 defineModule0(this, isOpen, vs, loc, packages);
138 }
139
140
141 /**
142 * Create the unnamed Module for the given ClassLoader.
143 *
144 * @see ClassLoader#getUnnamedModule
145 */
146 Module(ClassLoader loader) {
147 this.layer = null;
148 this.name = null;
149 this.loader = loader;
150 this.descriptor = null;
151 }
152
153
154 /**
155 * Creates a named module but without defining the module to the VM.
156 *
157 * @apiNote This constructor is for VM white-box testing.
158 */
159 Module(ClassLoader loader, ModuleDescriptor descriptor) {
160 this.layer = null;
161 this.name = descriptor.name();
162 this.loader = loader;
163 this.descriptor = descriptor;
164 }
165
166
167 /**
168 * Returns {@code true} if this module is a named module.
169 *
170 * @return {@code true} if this is a named module
171 *
172 * @see ClassLoader#getUnnamedModule()
173 */
174 public boolean isNamed() {
175 return name != null;
176 }
177
178 /**
179 * Returns the module name or {@code null} if this module is an unnamed
180 * module.
181 *
182 * @return The module name
183 */
184 public String getName() {
185 return name;
186 }
187
188 /**
189 * Returns the {@code ClassLoader} for this module.
190 *
191 * <p> If there is a security manager then its {@code checkPermission}
192 * method if first called with a {@code RuntimePermission("getClassLoader")}
193 * permission to check that the caller is allowed to get access to the
194 * class loader. </p>
195 *
196 * @return The class loader for this module
197 *
198 * @throws SecurityException
199 * If denied by the security manager
200 */
201 public ClassLoader getClassLoader() {
202 SecurityManager sm = System.getSecurityManager();
203 if (sm != null) {
204 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
205 }
206 return loader;
207 }
208
209 /**
210 * Returns the module descriptor for this module or {@code null} if this
211 * module is an unnamed module.
212 *
213 * @return The module descriptor for this module
214 */
215 public ModuleDescriptor getDescriptor() {
216 return descriptor;
217 }
218
219 /**
220 * Returns the module layer that contains this module or {@code null} if
221 * this module is not in a module layer.
222 *
223 * A module layer contains named modules and therefore this method always
224 * returns {@code null} when invoked on an unnamed module.
225 *
226 * <p> <a href="reflect/Proxy.html#dynamicmodule">Dynamic modules</a> are
227 * named modules that are generated at runtime. A dynamic module may or may
228 * not be in a module layer. </p>
229 *
230 * @return The module layer that contains this module
231 *
232 * @see java.lang.reflect.Proxy
233 */
234 public ModuleLayer getLayer() {
235 if (isNamed()) {
236 ModuleLayer layer = this.layer;
237 if (layer != null)
238 return layer;
239
240 // special-case java.base as it is created before the boot layer
241 if (loader == null && name.equals("java.base")) {
242 return ModuleLayer.boot();
243 }
244 }
245 return null;
246 }
247
248 // --
249
250 // special Module to mean "all unnamed modules"
251 private static final Module ALL_UNNAMED_MODULE = new Module(null);
252 private static final Set<Module> ALL_UNNAMED_MODULE_SET = Set.of(ALL_UNNAMED_MODULE);
253
254 // special Module to mean "everyone"
255 private static final Module EVERYONE_MODULE = new Module(null);
256 private static final Set<Module> EVERYONE_SET = Set.of(EVERYONE_MODULE);
257
258 /**
259 * The holder of data structures to support readability, exports, and
260 * service use added at runtime with the reflective APIs.
261 */
262 private static class ReflectionData {
263 /**
264 * A module (1st key) reads another module (2nd key)
265 */
266 static final WeakPairMap<Module, Module, Boolean> reads =
267 new WeakPairMap<>();
268
269 /**
270 * A module (1st key) exports or opens a package to another module
271 * (2nd key). The map value is a map of package name to a boolean
272 * that indicates if the package is opened.
273 */
274 static final WeakPairMap<Module, Module, Map<String, Boolean>> exports =
275 new WeakPairMap<>();
276
277 /**
278 * A module (1st key) uses a service (2nd key)
279 */
280 static final WeakPairMap<Module, Class<?>, Boolean> uses =
281 new WeakPairMap<>();
282 }
283
284
285 // -- readability --
286
287 // the modules that this module reads
288 private volatile Set<Module> reads;
289
290 /**
291 * Indicates if this module reads the given module. This method returns
292 * {@code true} if invoked to test if this module reads itself. It also
293 * returns {@code true} if invoked on an unnamed module (as unnamed
294 * modules read all modules).
295 *
296 * @param other
297 * The other module
298 *
299 * @return {@code true} if this module reads {@code other}
300 *
301 * @see #addReads(Module)
302 */
303 public boolean canRead(Module other) {
304 Objects.requireNonNull(other);
305
306 // an unnamed module reads all modules
307 if (!this.isNamed())
308 return true;
309
310 // all modules read themselves
311 if (other == this)
312 return true;
313
314 // check if this module reads other
315 if (other.isNamed()) {
316 Set<Module> reads = this.reads; // volatile read
317 if (reads != null && reads.contains(other))
318 return true;
319 }
320
321 // check if this module reads the other module reflectively
322 if (ReflectionData.reads.containsKeyPair(this, other))
323 return true;
324
325 // if other is an unnamed module then check if this module reads
326 // all unnamed modules
327 if (!other.isNamed()
328 && ReflectionData.reads.containsKeyPair(this, ALL_UNNAMED_MODULE))
329 return true;
330
331 return false;
332 }
333
334 /**
335 * If the caller's module is this module then update this module to read
336 * the given module.
337 *
338 * This method is a no-op if {@code other} is this module (all modules read
339 * themselves), this module is an unnamed module (as unnamed modules read
340 * all modules), or this module already reads {@code other}.
341 *
342 * @implNote <em>Read edges</em> added by this method are <em>weak</em> and
343 * do not prevent {@code other} from being GC'ed when this module is
344 * strongly reachable.
345 *
346 * @param other
347 * The other module
348 *
349 * @return this module
350 *
351 * @throws IllegalCallerException
352 * If this is a named module and the caller's module is not this
353 * module
354 *
355 * @see #canRead
356 */
357 @CallerSensitive
358 public Module addReads(Module other) {
359 Objects.requireNonNull(other);
360 if (this.isNamed()) {
361 Module caller = getCallerModule(Reflection.getCallerClass());
362 if (caller != this) {
363 throw new IllegalCallerException(caller + " != " + this);
364 }
365 implAddReads(other, true);
366 }
367 return this;
368 }
369
370 /**
371 * Updates this module to read another module.
372 *
373 * @apiNote Used by the --add-reads command line option.
374 */
375 void implAddReads(Module other) {
376 implAddReads(other, true);
377 }
378
379 /**
380 * Updates this module to read all unnamed modules.
381 *
382 * @apiNote Used by the --add-reads command line option.
383 */
384 void implAddReadsAllUnnamed() {
385 implAddReads(Module.ALL_UNNAMED_MODULE, true);
386 }
387
388 /**
389 * Updates this module to read another module without notifying the VM.
390 *
391 * @apiNote This method is for VM white-box testing.
392 */
393 void implAddReadsNoSync(Module other) {
394 implAddReads(other, false);
395 }
396
397 /**
398 * Makes the given {@code Module} readable to this module.
399 *
400 * If {@code syncVM} is {@code true} then the VM is notified.
401 */
402 private void implAddReads(Module other, boolean syncVM) {
403 Objects.requireNonNull(other);
404 if (!canRead(other)) {
405 // update VM first, just in case it fails
406 if (syncVM) {
407 if (other == ALL_UNNAMED_MODULE) {
408 addReads0(this, null);
409 } else {
410 addReads0(this, other);
411 }
412 }
413
414 // add reflective read
415 ReflectionData.reads.putIfAbsent(this, other, Boolean.TRUE);
416 }
417 }
418
419
420 // -- exported and open packages --
421
422 // the packages are open to other modules, can be null
423 // if the value contains EVERYONE_MODULE then the package is open to all
424 private volatile Map<String, Set<Module>> openPackages;
425
426 // the packages that are exported, can be null
427 // if the value contains EVERYONE_MODULE then the package is exported to all
428 private volatile Map<String, Set<Module>> exportedPackages;
429
430 /**
431 * Returns {@code true} if this module exports the given package to at
432 * least the given module.
433 *
434 * <p> This method returns {@code true} if invoked to test if a package in
435 * this module is exported to itself. It always returns {@code true} when
436 * invoked on an unnamed module. A package that is {@link #isOpen open} to
437 * the given module is considered exported to that module at run-time and
438 * so this method returns {@code true} if the package is open to the given
439 * module. </p>
440 *
441 * <p> This method does not check if the given module reads this module. </p>
442 *
443 * @param pn
444 * The package name
445 * @param other
446 * The other module
447 *
448 * @return {@code true} if this module exports the package to at least the
449 * given module
450 *
451 * @see ModuleDescriptor#exports()
452 * @see #addExports(String,Module)
453 */
454 public boolean isExported(String pn, Module other) {
455 Objects.requireNonNull(pn);
456 Objects.requireNonNull(other);
457 return implIsExportedOrOpen(pn, other, /*open*/false);
458 }
459
460 /**
461 * Returns {@code true} if this module has <em>opened</em> a package to at
462 * least the given module.
463 *
464 * <p> This method returns {@code true} if invoked to test if a package in
465 * this module is open to itself. It returns {@code true} when invoked on an
466 * {@link ModuleDescriptor#isOpen open} module with a package in the module.
467 * It always returns {@code true} when invoked on an unnamed module. </p>
468 *
469 * <p> This method does not check if the given module reads this module. </p>
470 *
471 * @param pn
472 * The package name
473 * @param other
474 * The other module
475 *
476 * @return {@code true} if this module has <em>opened</em> the package
477 * to at least the given module
478 *
479 * @see ModuleDescriptor#opens()
480 * @see #addOpens(String,Module)
481 * @see AccessibleObject#setAccessible(boolean)
482 * @see java.lang.invoke.MethodHandles#privateLookupIn
483 */
484 public boolean isOpen(String pn, Module other) {
485 Objects.requireNonNull(pn);
486 Objects.requireNonNull(other);
487 return implIsExportedOrOpen(pn, other, /*open*/true);
488 }
489
490 /**
491 * Returns {@code true} if this module exports the given package
492 * unconditionally.
493 *
494 * <p> This method always returns {@code true} when invoked on an unnamed
495 * module. A package that is {@link #isOpen(String) opened} unconditionally
496 * is considered exported unconditionally at run-time and so this method
497 * returns {@code true} if the package is opened unconditionally. </p>
498 *
499 * <p> This method does not check if the given module reads this module. </p>
500 *
501 * @param pn
502 * The package name
503 *
504 * @return {@code true} if this module exports the package unconditionally
505 *
506 * @see ModuleDescriptor#exports()
507 */
508 public boolean isExported(String pn) {
509 Objects.requireNonNull(pn);
510 return implIsExportedOrOpen(pn, EVERYONE_MODULE, /*open*/false);
511 }
512
513 /**
514 * Returns {@code true} if this module has <em>opened</em> a package
515 * unconditionally.
516 *
517 * <p> This method always returns {@code true} when invoked on an unnamed
518 * module. Additionally, it always returns {@code true} when invoked on an
519 * {@link ModuleDescriptor#isOpen open} module with a package in the
520 * module. </p>
521 *
522 * <p> This method does not check if the given module reads this module. </p>
523 *
524 * @param pn
525 * The package name
526 *
527 * @return {@code true} if this module has <em>opened</em> the package
528 * unconditionally
529 *
530 * @see ModuleDescriptor#opens()
531 */
532 public boolean isOpen(String pn) {
533 Objects.requireNonNull(pn);
534 return implIsExportedOrOpen(pn, EVERYONE_MODULE, /*open*/true);
535 }
536
537
538 /**
539 * Returns {@code true} if this module exports or opens the given package
540 * to the given module. If the other module is {@code EVERYONE_MODULE} then
541 * this method tests if the package is exported or opened unconditionally.
542 */
543 private boolean implIsExportedOrOpen(String pn, Module other, boolean open) {
544 // all packages in unnamed modules are open
545 if (!isNamed())
546 return true;
547
548 // all packages are exported/open to self
549 if (other == this && descriptor.packages().contains(pn))
550 return true;
551
552 // all packages in open and automatic modules are open
553 if (descriptor.isOpen() || descriptor.isAutomatic())
554 return descriptor.packages().contains(pn);
555
556 // exported/opened via module declaration/descriptor
557 if (isStaticallyExportedOrOpen(pn, other, open))
558 return true;
559
560 // exported via addExports/addOpens
561 if (isReflectivelyExportedOrOpen(pn, other, open))
562 return true;
563
564 // not exported or open to other
565 return false;
566 }
567
568 /**
569 * Returns {@code true} if this module exports or opens a package to
570 * the given module via its module declaration or CLI options.
571 */
572 private boolean isStaticallyExportedOrOpen(String pn, Module other, boolean open) {
573 // test if package is open to everyone or <other>
574 Map<String, Set<Module>> openPackages = this.openPackages;
575 if (openPackages != null && allows(openPackages.get(pn), other)) {
576 return true;
577 }
578
579 if (!open) {
580 // test package is exported to everyone or <other>
581 Map<String, Set<Module>> exportedPackages = this.exportedPackages;
582 if (exportedPackages != null && allows(exportedPackages.get(pn), other)) {
583 return true;
584 }
585 }
586
587 return false;
588 }
589
590 /**
591 * Returns {@code true} if targets is non-null and contains EVERYONE_MODULE
592 * or the given module. Also returns true if the given module is an unnamed
593 * module and targets contains ALL_UNNAMED_MODULE.
594 */
595 private boolean allows(Set<Module> targets, Module module) {
596 if (targets != null) {
597 if (targets.contains(EVERYONE_MODULE))
598 return true;
599 if (module != EVERYONE_MODULE) {
600 if (targets.contains(module))
601 return true;
602 if (!module.isNamed() && targets.contains(ALL_UNNAMED_MODULE))
603 return true;
604 }
605 }
606 return false;
607 }
608
609 /**
610 * Returns {@code true} if this module reflectively exports or opens the
611 * given package to the given module.
612 */
613 private boolean isReflectivelyExportedOrOpen(String pn, Module other, boolean open) {
614 // exported or open to all modules
615 Map<String, Boolean> exports = ReflectionData.exports.get(this, EVERYONE_MODULE);
616 if (exports != null) {
617 Boolean b = exports.get(pn);
618 if (b != null) {
619 boolean isOpen = b.booleanValue();
620 if (!open || isOpen) return true;
621 }
622 }
623
624 if (other != EVERYONE_MODULE) {
625
626 // exported or open to other
627 exports = ReflectionData.exports.get(this, other);
628 if (exports != null) {
629 Boolean b = exports.get(pn);
630 if (b != null) {
631 boolean isOpen = b.booleanValue();
632 if (!open || isOpen) return true;
633 }
634 }
635
636 // other is an unnamed module && exported or open to all unnamed
637 if (!other.isNamed()) {
638 exports = ReflectionData.exports.get(this, ALL_UNNAMED_MODULE);
639 if (exports != null) {
640 Boolean b = exports.get(pn);
641 if (b != null) {
642 boolean isOpen = b.booleanValue();
643 if (!open || isOpen) return true;
644 }
645 }
646 }
647
648 }
649
650 return false;
651 }
652
653 /**
654 * Returns {@code true} if this module reflectively exports the
655 * given package to the given module.
656 */
657 boolean isReflectivelyExported(String pn, Module other) {
658 return isReflectivelyExportedOrOpen(pn, other, false);
659 }
660
661 /**
662 * Returns {@code true} if this module reflectively opens the
663 * given package to the given module.
664 */
665 boolean isReflectivelyOpened(String pn, Module other) {
666 return isReflectivelyExportedOrOpen(pn, other, true);
667 }
668
669
670 /**
671 * If the caller's module is this module then update this module to export
672 * the given package to the given module.
673 *
674 * <p> This method has no effect if the package is already exported (or
675 * <em>open</em>) to the given module. </p>
676 *
677 * @apiNote As specified in section 5.4.3 of the <cite>The Java™
678 * Virtual Machine Specification </cite>, if an attempt to resolve a
679 * symbolic reference fails because of a linkage error, then subsequent
680 * attempts to resolve the reference always fail with the same error that
681 * was thrown as a result of the initial resolution attempt.
682 *
683 * @param pn
684 * The package name
685 * @param other
686 * The module
687 *
688 * @return this module
689 *
690 * @throws IllegalArgumentException
691 * If {@code pn} is {@code null}, or this is a named module and the
692 * package {@code pn} is not a package in this module
693 * @throws IllegalCallerException
694 * If this is a named module and the caller's module is not this
695 * module
696 *
697 * @jvms 5.4.3 Resolution
698 * @see #isExported(String,Module)
699 */
700 @CallerSensitive
701 public Module addExports(String pn, Module other) {
702 if (pn == null)
703 throw new IllegalArgumentException("package is null");
704 Objects.requireNonNull(other);
705
706 if (isNamed()) {
707 Module caller = getCallerModule(Reflection.getCallerClass());
708 if (caller != this) {
709 throw new IllegalCallerException(caller + " != " + this);
710 }
711 implAddExportsOrOpens(pn, other, /*open*/false, /*syncVM*/true);
712 }
713
714 return this;
715 }
716
717 /**
718 * If this module has <em>opened</em> a package to at least the caller
719 * module then update this module to open the package to the given module.
720 * Opening a package with this method allows all types in the package,
721 * and all their members, not just public types and their public members,
722 * to be reflected on by the given module when using APIs that support
723 * private access or a way to bypass or suppress default Java language
724 * access control checks.
725 *
726 * <p> This method has no effect if the package is already <em>open</em>
727 * to the given module. </p>
728 *
729 * @apiNote This method can be used for cases where a <em>consumer
730 * module</em> uses a qualified opens to open a package to an <em>API
731 * module</em> but where the reflective access to the members of classes in
732 * the consumer module is delegated to code in another module. Code in the
733 * API module can use this method to open the package in the consumer module
734 * to the other module.
735 *
736 * @param pn
737 * The package name
738 * @param other
739 * The module
740 *
741 * @return this module
742 *
743 * @throws IllegalArgumentException
744 * If {@code pn} is {@code null}, or this is a named module and the
745 * package {@code pn} is not a package in this module
746 * @throws IllegalCallerException
747 * If this is a named module and this module has not opened the
748 * package to at least the caller's module
749 *
750 * @see #isOpen(String,Module)
751 * @see AccessibleObject#setAccessible(boolean)
752 * @see java.lang.invoke.MethodHandles#privateLookupIn
753 */
754 @CallerSensitive
755 public Module addOpens(String pn, Module other) {
756 if (pn == null)
757 throw new IllegalArgumentException("package is null");
758 Objects.requireNonNull(other);
759
760 if (isNamed()) {
761 Module caller = getCallerModule(Reflection.getCallerClass());
762 if (caller != this && (caller == null || !isOpen(pn, caller)))
763 throw new IllegalCallerException(pn + " is not open to " + caller);
764 implAddExportsOrOpens(pn, other, /*open*/true, /*syncVM*/true);
765 }
766
767 return this;
768 }
769
770
771 /**
772 * Updates this module to export a package unconditionally.
773 *
774 * @apiNote This method is for JDK tests only.
775 */
776 void implAddExports(String pn) {
777 implAddExportsOrOpens(pn, Module.EVERYONE_MODULE, false, true);
778 }
779
780 /**
781 * Updates this module to export a package to another module.
782 *
783 * @apiNote Used by Instrumentation::redefineModule and --add-exports
784 */
785 void implAddExports(String pn, Module other) {
786 implAddExportsOrOpens(pn, other, false, true);
787 }
788
789 /**
790 * Updates this module to export a package to all unnamed modules.
791 *
792 * @apiNote Used by the --add-exports command line option.
793 */
794 void implAddExportsToAllUnnamed(String pn) {
795 implAddExportsOrOpens(pn, Module.ALL_UNNAMED_MODULE, false, true);
796 }
797
798 /**
799 * Updates this export to export a package unconditionally without
800 * notifying the VM.
801 *
802 * @apiNote This method is for VM white-box testing.
803 */
804 void implAddExportsNoSync(String pn) {
805 implAddExportsOrOpens(pn.replace('/', '.'), Module.EVERYONE_MODULE, false, false);
806 }
807
808 /**
809 * Updates a module to export a package to another module without
810 * notifying the VM.
811 *
812 * @apiNote This method is for VM white-box testing.
813 */
814 void implAddExportsNoSync(String pn, Module other) {
815 implAddExportsOrOpens(pn.replace('/', '.'), other, false, false);
816 }
817
818 /**
819 * Updates this module to open a package unconditionally.
820 *
821 * @apiNote This method is for JDK tests only.
822 */
823 void implAddOpens(String pn) {
824 implAddExportsOrOpens(pn, Module.EVERYONE_MODULE, true, true);
825 }
826
827 /**
828 * Updates this module to open a package to another module.
829 *
830 * @apiNote Used by Instrumentation::redefineModule and --add-opens
831 */
832 void implAddOpens(String pn, Module other) {
833 implAddExportsOrOpens(pn, other, true, true);
834 }
835
836 /**
837 * Updates this module to open a package to all unnamed modules.
838 *
839 * @apiNote Used by the --add-opens command line option.
840 */
841 void implAddOpensToAllUnnamed(String pn) {
842 implAddExportsOrOpens(pn, Module.ALL_UNNAMED_MODULE, true, true);
843 }
844
845 /**
846 * Updates a module to export or open a module to another module.
847 *
848 * If {@code syncVM} is {@code true} then the VM is notified.
849 */
850 private void implAddExportsOrOpens(String pn,
851 Module other,
852 boolean open,
853 boolean syncVM) {
854 Objects.requireNonNull(other);
855 Objects.requireNonNull(pn);
856
857 // all packages are open in unnamed, open, and automatic modules
858 if (!isNamed() || descriptor.isOpen() || descriptor.isAutomatic())
859 return;
860
861 // check if the package is already exported/open to other
862 if (implIsExportedOrOpen(pn, other, open)) {
863
864 // if the package is exported/open for illegal access then we need
865 // to record that it has also been exported/opened reflectively so
866 // that the IllegalAccessLogger doesn't emit a warning.
867 boolean needToAdd = false;
868 if (!other.isNamed()) {
869 IllegalAccessLogger l = IllegalAccessLogger.illegalAccessLogger();
870 if (l != null) {
871 if (open) {
872 needToAdd = l.isOpenForIllegalAccess(this, pn);
873 } else {
874 needToAdd = l.isExportedForIllegalAccess(this, pn);
875 }
876 }
877 }
878 if (!needToAdd) {
879 // nothing to do
880 return;
881 }
882 }
883
884 // can only export a package in the module
885 if (!descriptor.packages().contains(pn)) {
886 throw new IllegalArgumentException("package " + pn
887 + " not in contents");
888 }
889
890 // update VM first, just in case it fails
891 if (syncVM) {
892 if (other == EVERYONE_MODULE) {
893 addExportsToAll0(this, pn);
894 } else if (other == ALL_UNNAMED_MODULE) {
895 addExportsToAllUnnamed0(this, pn);
896 } else {
897 addExports0(this, pn, other);
898 }
899 }
900
901 // add package name to exports if absent
902 Map<String, Boolean> map = ReflectionData.exports
903 .computeIfAbsent(this, other,
904 (m1, m2) -> new ConcurrentHashMap<>());
905 if (open) {
906 map.put(pn, Boolean.TRUE); // may need to promote from FALSE to TRUE
907 } else {
908 map.putIfAbsent(pn, Boolean.FALSE);
909 }
910 }
911
912 /**
913 * Updates a module to open all packages returned by the given iterator to
914 * all unnamed modules.
915 *
916 * @apiNote Used during startup to open packages for illegal access.
917 */
918 void implAddOpensToAllUnnamed(Iterator<String> iterator) {
919 if (jdk.internal.misc.VM.isModuleSystemInited()) {
920 throw new IllegalStateException("Module system already initialized");
921 }
922
923 // replace this module's openPackages map with a new map that opens
924 // the packages to all unnamed modules.
925 Map<String, Set<Module>> openPackages = this.openPackages;
926 if (openPackages == null) {
927 openPackages = new HashMap<>();
928 } else {
929 openPackages = new HashMap<>(openPackages);
930 }
931 while (iterator.hasNext()) {
932 String pn = iterator.next();
933 Set<Module> prev = openPackages.putIfAbsent(pn, ALL_UNNAMED_MODULE_SET);
934 if (prev != null) {
935 prev.add(ALL_UNNAMED_MODULE);
936 }
937
938 // update VM to export the package
939 addExportsToAllUnnamed0(this, pn);
940 }
941 this.openPackages = openPackages;
942 }
943
944
945 // -- services --
946
947 /**
948 * If the caller's module is this module then update this module to add a
949 * service dependence on the given service type. This method is intended
950 * for use by frameworks that invoke {@link java.util.ServiceLoader
951 * ServiceLoader} on behalf of other modules or where the framework is
952 * passed a reference to the service type by other code. This method is
953 * a no-op when invoked on an unnamed module or an automatic module.
954 *
955 * <p> This method does not cause {@link Configuration#resolveAndBind
956 * resolveAndBind} to be re-run. </p>
957 *
958 * @param service
959 * The service type
960 *
961 * @return this module
962 *
963 * @throws IllegalCallerException
964 * If this is a named module and the caller's module is not this
965 * module
966 *
967 * @see #canUse(Class)
968 * @see ModuleDescriptor#uses()
969 */
970 @CallerSensitive
971 public Module addUses(Class<?> service) {
972 Objects.requireNonNull(service);
973
974 if (isNamed() && !descriptor.isAutomatic()) {
975 Module caller = getCallerModule(Reflection.getCallerClass());
976 if (caller != this) {
977 throw new IllegalCallerException(caller + " != " + this);
978 }
979 implAddUses(service);
980 }
981
982 return this;
983 }
984
985 /**
986 * Update this module to add a service dependence on the given service
987 * type.
988 */
989 void implAddUses(Class<?> service) {
990 if (!canUse(service)) {
991 ReflectionData.uses.putIfAbsent(this, service, Boolean.TRUE);
992 }
993 }
994
995
996 /**
997 * Indicates if this module has a service dependence on the given service
998 * type. This method always returns {@code true} when invoked on an unnamed
999 * module or an automatic module.
1000 *
1001 * @param service
1002 * The service type
1003 *
1004 * @return {@code true} if this module uses service type {@code st}
1005 *
1006 * @see #addUses(Class)
1007 */
1008 public boolean canUse(Class<?> service) {
1009 Objects.requireNonNull(service);
1010
1011 if (!isNamed())
1012 return true;
1013
1014 if (descriptor.isAutomatic())
1015 return true;
1016
1017 // uses was declared
1018 if (descriptor.uses().contains(service.getName()))
1019 return true;
1020
1021 // uses added via addUses
1022 return ReflectionData.uses.containsKeyPair(this, service);
1023 }
1024
1025
1026
1027 // -- packages --
1028
1029 /**
1030 * Returns the set of package names for the packages in this module.
1031 *
1032 * <p> For named modules, the returned set contains an element for each
1033 * package in the module. </p>
1034 *
1035 * <p> For unnamed modules, this method is the equivalent to invoking the
1036 * {@link ClassLoader#getDefinedPackages() getDefinedPackages} method of
1037 * this module's class loader and returning the set of package names. </p>
1038 *
1039 * @return the set of the package names of the packages in this module
1040 */
1041 public Set<String> getPackages() {
1042 if (isNamed()) {
1043 return descriptor.packages();
1044 } else {
1045 // unnamed module
1046 Stream<Package> packages;
1047 if (loader == null) {
1048 packages = BootLoader.packages();
1049 } else {
1050 packages = loader.packages();
1051 }
1052 return packages.map(Package::getName).collect(Collectors.toSet());
1053 }
1054 }
1055
1056
1057 // -- creating Module objects --
1058
1059 /**
1060 * Defines all module in a configuration to the runtime.
1061 *
1062 * @return a map of module name to runtime {@code Module}
1063 *
1064 * @throws IllegalArgumentException
1065 * If defining any of the modules to the VM fails
1066 */
1067 static Map<String, Module> defineModules(Configuration cf,
1068 Function<String, ClassLoader> clf,
1069 ModuleLayer layer)
1070 {
1071 boolean isBootLayer = (ModuleLayer.boot() == null);
1072
1073 int cap = (int)(cf.modules().size() / 0.75f + 1.0f);
1074 Map<String, Module> nameToModule = new HashMap<>(cap);
1075 Map<String, ClassLoader> nameToLoader = new HashMap<>(cap);
1076
1077 Set<ClassLoader> loaders = new HashSet<>();
1078 boolean hasPlatformModules = false;
1079
1080 // map each module to a class loader
1081 for (ResolvedModule resolvedModule : cf.modules()) {
1082 String name = resolvedModule.name();
1083 ClassLoader loader = clf.apply(name);
1084 nameToLoader.put(name, loader);
1085 if (loader == null || loader == ClassLoaders.platformClassLoader()) {
1086 if (!(clf instanceof ModuleLoaderMap.Mapper)) {
1087 throw new IllegalArgumentException("loader can't be 'null'"
1088 + " or the platform class loader");
1089 }
1090 hasPlatformModules = true;
1091 } else {
1092 loaders.add(loader);
1093 }
1094 }
1095
1096 // define each module in the configuration to the VM
1097 for (ResolvedModule resolvedModule : cf.modules()) {
1098 ModuleReference mref = resolvedModule.reference();
1099 ModuleDescriptor descriptor = mref.descriptor();
1100 String name = descriptor.name();
1101 ClassLoader loader = nameToLoader.get(name);
1102 Module m;
1103 if (loader == null && name.equals("java.base")) {
1104 // java.base is already defined to the VM
1105 m = Object.class.getModule();
1106 } else {
1107 URI uri = mref.location().orElse(null);
1108 m = new Module(layer, loader, descriptor, uri);
1109 }
1110 nameToModule.put(name, m);
1111 }
1112
1113 // setup readability and exports/opens
1114 for (ResolvedModule resolvedModule : cf.modules()) {
1115 ModuleReference mref = resolvedModule.reference();
1116 ModuleDescriptor descriptor = mref.descriptor();
1117
1118 String mn = descriptor.name();
1119 Module m = nameToModule.get(mn);
1120 assert m != null;
1121
1122 // reads
1123 Set<Module> reads = new HashSet<>();
1124
1125 // name -> source Module when in parent layer
1126 Map<String, Module> nameToSource = Collections.emptyMap();
1127
1128 for (ResolvedModule other : resolvedModule.reads()) {
1129 Module m2 = null;
1130 if (other.configuration() == cf) {
1131 // this configuration
1132 m2 = nameToModule.get(other.name());
1133 assert m2 != null;
1134 } else {
1135 // parent layer
1136 for (ModuleLayer parent: layer.parents()) {
1137 m2 = findModule(parent, other);
1138 if (m2 != null)
1139 break;
1140 }
1141 assert m2 != null;
1142 if (nameToSource.isEmpty())
1143 nameToSource = new HashMap<>();
1144 nameToSource.put(other.name(), m2);
1145 }
1146 reads.add(m2);
1147
1148 // update VM view
1149 addReads0(m, m2);
1150 }
1151 m.reads = reads;
1152
1153 // automatic modules read all unnamed modules
1154 if (descriptor.isAutomatic()) {
1155 m.implAddReads(ALL_UNNAMED_MODULE, true);
1156 }
1157
1158 // exports and opens, skipped for open and automatic
1159 if (!descriptor.isOpen() && !descriptor.isAutomatic()) {
1160 if (isBootLayer && descriptor.opens().isEmpty()) {
1161 // no open packages, no qualified exports to modules in parent layers
1162 initExports(m, nameToModule);
1163 } else {
1164 initExportsAndOpens(m, nameToSource, nameToModule, layer.parents());
1165 }
1166 }
1167 }
1168
1169 // if there are modules defined to the boot or platform class loaders
1170 // then register the modules in the class loader's services catalog
1171 if (hasPlatformModules) {
1172 ClassLoader pcl = ClassLoaders.platformClassLoader();
1173 ServicesCatalog bootCatalog = BootLoader.getServicesCatalog();
1174 ServicesCatalog pclCatalog = ServicesCatalog.getServicesCatalog(pcl);
1175 for (ResolvedModule resolvedModule : cf.modules()) {
1176 ModuleReference mref = resolvedModule.reference();
1177 ModuleDescriptor descriptor = mref.descriptor();
1178 if (!descriptor.provides().isEmpty()) {
1179 String name = descriptor.name();
1180 Module m = nameToModule.get(name);
1181 ClassLoader loader = nameToLoader.get(name);
1182 if (loader == null) {
1183 bootCatalog.register(m);
1184 } else if (loader == pcl) {
1185 pclCatalog.register(m);
1186 }
1187 }
1188 }
1189 }
1190
1191 // record that there is a layer with modules defined to the class loader
1192 for (ClassLoader loader : loaders) {
1193 layer.bindToLoader(loader);
1194 }
1195
1196 return nameToModule;
1197 }
1198
1199 /**
1200 * Find the runtime Module corresponding to the given ResolvedModule
1201 * in the given parent layer (or its parents).
1202 */
1203 private static Module findModule(ModuleLayer parent,
1204 ResolvedModule resolvedModule) {
1205 Configuration cf = resolvedModule.configuration();
1206 String dn = resolvedModule.name();
1207 return parent.layers()
1208 .filter(l -> l.configuration() == cf)
1209 .findAny()
1210 .map(layer -> {
1211 Optional<Module> om = layer.findModule(dn);
1212 assert om.isPresent() : dn + " not found in layer";
1213 Module m = om.get();
1214 assert m.getLayer() == layer : m + " not in expected layer";
1215 return m;
1216 })
1217 .orElse(null);
1218 }
1219
1220 /**
1221 * Initialize/setup a module's exports.
1222 *
1223 * @param m the module
1224 * @param nameToModule map of module name to Module (for qualified exports)
1225 */
1226 private static void initExports(Module m, Map<String, Module> nameToModule) {
1227 Map<String, Set<Module>> exportedPackages = new HashMap<>();
1228
1229 for (Exports exports : m.getDescriptor().exports()) {
1230 String source = exports.source();
1231 if (exports.isQualified()) {
1232 // qualified exports
1233 Set<Module> targets = new HashSet<>();
1234 for (String target : exports.targets()) {
1235 Module m2 = nameToModule.get(target);
1236 if (m2 != null) {
1237 addExports0(m, source, m2);
1238 targets.add(m2);
1239 }
1240 }
1241 if (!targets.isEmpty()) {
1242 exportedPackages.put(source, targets);
1243 }
1244 } else {
1245 // unqualified exports
1246 addExportsToAll0(m, source);
1247 exportedPackages.put(source, EVERYONE_SET);
1248 }
1249 }
1250
1251 if (!exportedPackages.isEmpty())
1252 m.exportedPackages = exportedPackages;
1253 }
1254
1255 /**
1256 * Initialize/setup a module's exports.
1257 *
1258 * @param m the module
1259 * @param nameToSource map of module name to Module for modules that m reads
1260 * @param nameToModule map of module name to Module for modules in the layer
1261 * under construction
1262 * @param parents the parent layers
1263 */
1264 private static void initExportsAndOpens(Module m,
1265 Map<String, Module> nameToSource,
1266 Map<String, Module> nameToModule,
1267 List<ModuleLayer> parents) {
1268 ModuleDescriptor descriptor = m.getDescriptor();
1269 Map<String, Set<Module>> openPackages = new HashMap<>();
1270 Map<String, Set<Module>> exportedPackages = new HashMap<>();
1271
1272 // process the open packages first
1273 for (Opens opens : descriptor.opens()) {
1274 String source = opens.source();
1275
1276 if (opens.isQualified()) {
1277 // qualified opens
1278 Set<Module> targets = new HashSet<>();
1279 for (String target : opens.targets()) {
1280 Module m2 = findModule(target, nameToSource, nameToModule, parents);
1281 if (m2 != null) {
1282 addExports0(m, source, m2);
1283 targets.add(m2);
1284 }
1285 }
1286 if (!targets.isEmpty()) {
1287 openPackages.put(source, targets);
1288 }
1289 } else {
1290 // unqualified opens
1291 addExportsToAll0(m, source);
1292 openPackages.put(source, EVERYONE_SET);
1293 }
1294 }
1295
1296 // next the exports, skipping exports when the package is open
1297 for (Exports exports : descriptor.exports()) {
1298 String source = exports.source();
1299
1300 // skip export if package is already open to everyone
1301 Set<Module> openToTargets = openPackages.get(source);
1302 if (openToTargets != null && openToTargets.contains(EVERYONE_MODULE))
1303 continue;
1304
1305 if (exports.isQualified()) {
1306 // qualified exports
1307 Set<Module> targets = new HashSet<>();
1308 for (String target : exports.targets()) {
1309 Module m2 = findModule(target, nameToSource, nameToModule, parents);
1310 if (m2 != null) {
1311 // skip qualified export if already open to m2
1312 if (openToTargets == null || !openToTargets.contains(m2)) {
1313 addExports0(m, source, m2);
1314 targets.add(m2);
1315 }
1316 }
1317 }
1318 if (!targets.isEmpty()) {
1319 exportedPackages.put(source, targets);
1320 }
1321 } else {
1322 // unqualified exports
1323 addExportsToAll0(m, source);
1324 exportedPackages.put(source, EVERYONE_SET);
1325 }
1326 }
1327
1328 if (!openPackages.isEmpty())
1329 m.openPackages = openPackages;
1330 if (!exportedPackages.isEmpty())
1331 m.exportedPackages = exportedPackages;
1332 }
1333
1334 /**
1335 * Find the runtime Module with the given name. The module name is the
1336 * name of a target module in a qualified exports or opens directive.
1337 *
1338 * @param target The target module to find
1339 * @param nameToSource The modules in parent layers that are read
1340 * @param nameToModule The modules in the layer under construction
1341 * @param parents The parent layers
1342 */
1343 private static Module findModule(String target,
1344 Map<String, Module> nameToSource,
1345 Map<String, Module> nameToModule,
1346 List<ModuleLayer> parents) {
1347 Module m = nameToSource.get(target);
1348 if (m == null) {
1349 m = nameToModule.get(target);
1350 if (m == null) {
1351 for (ModuleLayer parent : parents) {
1352 m = parent.findModule(target).orElse(null);
1353 if (m != null) break;
1354 }
1355 }
1356 }
1357 return m;
1358 }
1359
1360
1361 // -- annotations --
1362
1363 /**
1364 * {@inheritDoc}
1365 * This method returns {@code null} when invoked on an unnamed module.
1366 */
1367 @Override
1368 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
1369 return moduleInfoClass().getDeclaredAnnotation(annotationClass);
1370 }
1371
1372 /**
1373 * {@inheritDoc}
1374 * This method returns an empty array when invoked on an unnamed module.
1375 */
1376 @Override
1377 public Annotation[] getAnnotations() {
1378 return moduleInfoClass().getAnnotations();
1379 }
1380
1381 /**
1382 * {@inheritDoc}
1383 * This method returns an empty array when invoked on an unnamed module.
1384 */
1385 @Override
1386 public Annotation[] getDeclaredAnnotations() {
1387 return moduleInfoClass().getDeclaredAnnotations();
1388 }
1389
1390 // cached class file with annotations
1391 private volatile Class<?> moduleInfoClass;
1392
1393 private Class<?> moduleInfoClass() {
1394 Class<?> clazz = this.moduleInfoClass;
1395 if (clazz != null)
1396 return clazz;
1397
1398 synchronized (this) {
1399 clazz = this.moduleInfoClass;
1400 if (clazz == null) {
1401 if (isNamed()) {
1402 PrivilegedAction<Class<?>> pa = this::loadModuleInfoClass;
1403 clazz = AccessController.doPrivileged(pa);
1404 }
1405 if (clazz == null) {
1406 class DummyModuleInfo { }
1407 clazz = DummyModuleInfo.class;
1408 }
1409 this.moduleInfoClass = clazz;
1410 }
1411 return clazz;
1412 }
1413 }
1414
1415 private Class<?> loadModuleInfoClass() {
1416 Class<?> clazz = null;
1417 try (InputStream in = getResourceAsStream("module-info.class")) {
1418 if (in != null)
1419 clazz = loadModuleInfoClass(in);
1420 } catch (Exception ignore) { }
1421 return clazz;
1422 }
1423
1424 /**
1425 * Loads module-info.class as a package-private interface in a class loader
1426 * that is a child of this module's class loader.
1427 */
1428 private Class<?> loadModuleInfoClass(InputStream in) throws IOException {
1429 final String MODULE_INFO = "module-info";
1430
1431 ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS
1432 + ClassWriter.COMPUTE_FRAMES);
1433
1434 ClassVisitor cv = new ClassVisitor(Opcodes.ASM6, cw) {
1435 @Override
1436 public void visit(int version,
1437 int access,
1438 String name,
1439 String signature,
1440 String superName,
1441 String[] interfaces) {
1442 cw.visit(version,
1443 Opcodes.ACC_INTERFACE
1444 + Opcodes.ACC_ABSTRACT
1445 + Opcodes.ACC_SYNTHETIC,
1446 MODULE_INFO,
1447 null,
1448 "java/lang/Object",
1449 null);
1450 }
1451 @Override
1452 public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
1453 // keep annotations
1454 return super.visitAnnotation(desc, visible);
1455 }
1456 @Override
1457 public void visitAttribute(Attribute attr) {
1458 // drop non-annotation attributes
1459 }
1460 @Override
1461 public ModuleVisitor visitModule(String name, int flags, String version) {
1462 // drop Module attribute
1463 return null;
1464 }
1465 };
1466
1467 ClassReader cr = new ClassReader(in);
1468 cr.accept(cv, 0);
1469 byte[] bytes = cw.toByteArray();
1470
1471 ClassLoader cl = new ClassLoader(loader) {
1472 @Override
1473 protected Class<?> findClass(String cn)throws ClassNotFoundException {
1474 if (cn.equals(MODULE_INFO)) {
1475 return super.defineClass(cn, bytes, 0, bytes.length);
1476 } else {
1477 throw new ClassNotFoundException(cn);
1478 }
1479 }
1480 };
1481
1482 try {
1483 return cl.loadClass(MODULE_INFO);
1484 } catch (ClassNotFoundException e) {
1485 throw new InternalError(e);
1486 }
1487 }
1488
1489
1490 // -- misc --
1491
1492
1493 /**
1494 * Returns an input stream for reading a resource in this module.
1495 * The {@code name} parameter is a {@code '/'}-separated path name that
1496 * identifies the resource. As with {@link Class#getResourceAsStream
1497 * Class.getResourceAsStream}, this method delegates to the module's class
1498 * loader {@link ClassLoader#findResource(String,String)
1499 * findResource(String,String)} method, invoking it with the module name
1500 * (or {@code null} when the module is unnamed) and the name of the
1501 * resource. If the resource name has a leading slash then it is dropped
1502 * before delegation.
1503 *
1504 * <p> A resource in a named module may be <em>encapsulated</em> so that
1505 * it cannot be located by code in other modules. Whether a resource can be
1506 * located or not is determined as follows: </p>
1507 *
1508 * <ul>
1509 * <li> If the resource name ends with "{@code .class}" then it is not
1510 * encapsulated. </li>
1511 *
1512 * <li> A <em>package name</em> is derived from the resource name. If
1513 * the package name is a {@linkplain #getPackages() package} in the
1514 * module then the resource can only be located by the caller of this
1515 * method when the package is {@linkplain #isOpen(String,Module) open}
1516 * to at least the caller's module. If the resource is not in a
1517 * package in the module then the resource is not encapsulated. </li>
1518 * </ul>
1519 *
1520 * <p> In the above, the <em>package name</em> for a resource is derived
1521 * from the subsequence of characters that precedes the last {@code '/'} in
1522 * the name and then replacing each {@code '/'} character in the subsequence
1523 * with {@code '.'}. A leading slash is ignored when deriving the package
1524 * name. As an example, the package name derived for a resource named
1525 * "{@code a/b/c/foo.properties}" is "{@code a.b.c}". A resource name
1526 * with the name "{@code META-INF/MANIFEST.MF}" is never encapsulated
1527 * because "{@code META-INF}" is not a legal package name. </p>
1528 *
1529 * <p> This method returns {@code null} if the resource is not in this
1530 * module, the resource is encapsulated and cannot be located by the caller,
1531 * or access to the resource is denied by the security manager. </p>
1532 *
1533 * @param name
1534 * The resource name
1535 *
1536 * @return An input stream for reading the resource or {@code null}
1537 *
1538 * @throws IOException
1539 * If an I/O error occurs
1540 *
1541 * @see Class#getResourceAsStream(String)
1542 */
1543 @CallerSensitive
1544 public InputStream getResourceAsStream(String name) throws IOException {
1545 if (name.startsWith("/")) {
1546 name = name.substring(1);
1547 }
1548
1549 if (isNamed() && Resources.canEncapsulate(name)) {
1550 Module caller = getCallerModule(Reflection.getCallerClass());
1551 if (caller != this && caller != Object.class.getModule()) {
1552 String pn = Resources.toPackageName(name);
1553 if (getPackages().contains(pn)) {
1554 if (caller == null && !isOpen(pn)) {
1555 // no caller, package not open
1556 return null;
1557 }
1558 if (!isOpen(pn, caller)) {
1559 // package not open to caller
1560 return null;
1561 }
1562 }
1563 }
1564 }
1565
1566 String mn = this.name;
1567
1568 // special-case built-in class loaders to avoid URL connection
1569 if (loader == null) {
1570 return BootLoader.findResourceAsStream(mn, name);
1571 } else if (loader instanceof BuiltinClassLoader) {
1572 return ((BuiltinClassLoader) loader).findResourceAsStream(mn, name);
1573 }
1574
1575 // locate resource in module
1576 URL url = loader.findResource(mn, name);
1577 if (url != null) {
1578 try {
1579 return url.openStream();
1580 } catch (SecurityException e) { }
1581 }
1582
1583 return null;
1584 }
1585
1586 /**
1587 * Returns the string representation of this module. For a named module,
1588 * the representation is the string {@code "module"}, followed by a space,
1589 * and then the module name. For an unnamed module, the representation is
1590 * the string {@code "unnamed module"}, followed by a space, and then an
1591 * implementation specific string that identifies the unnamed module.
1592 *
1593 * @return The string representation of this module
1594 */
1595 @Override
1596 public String toString() {
1597 if (isNamed()) {
1598 return "module " + name;
1599 } else {
1600 String id = Integer.toHexString(System.identityHashCode(this));
1601 return "unnamed module @" + id;
1602 }
1603 }
1604
1605 /**
1606 * Returns the module that a given caller class is a member of. Returns
1607 * {@code null} if the caller is {@code null}.
1608 */
1609 private Module getCallerModule(Class<?> caller) {
1610 return (caller != null) ? caller.getModule() : null;
1611 }
1612
1613
1614 // -- native methods --
1615
1616 // JVM_DefineModule
1617 private static native void defineModule0(Module module,
1618 boolean isOpen,
1619 String version,
1620 String location,
1621 String[] pns);
1622
1623 // JVM_AddReadsModule
1624 private static native void addReads0(Module from, Module to);
1625
1626 // JVM_AddModuleExports
1627 private static native void addExports0(Module from, String pn, Module to);
1628
1629 // JVM_AddModuleExportsToAll
1630 private static native void addExportsToAll0(Module from, String pn);
1631
1632 // JVM_AddModuleExportsToAllUnnamed
1633 private static native void addExportsToAllUnnamed0(Module from, String pn);
1634 }