1 /*
2 * Copyright (c) 2013, 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.module;
27
28 import java.io.PrintStream;
29 import java.lang.module.ModuleDescriptor.Provides;
30 import java.lang.module.ModuleDescriptor.Requires.Modifier;
31 import java.lang.reflect.Layer;
32 import java.util.ArrayDeque;
33 import java.util.ArrayList;
34 import java.util.Arrays;
35 import java.util.Collection;
36 import java.util.Deque;
37 import java.util.HashMap;
38 import java.util.HashSet;
39 import java.util.LinkedHashSet;
40 import java.util.List;
41 import java.util.Map;
42 import java.util.Objects;
43 import java.util.Optional;
44 import java.util.Set;
45 import java.util.StringJoiner;
46 import java.util.stream.Collectors;
47
48 import jdk.internal.module.ModuleHashes;
49 import jdk.internal.module.ModuleReferenceImpl;
50
51 /**
52 * The resolver used by {@link Configuration#resolve} and {@link
53 * Configuration#resolveAndBind}.
54 *
55 * @implNote The resolver is used at VM startup and so deliberately avoids
56 * using lambda and stream usages in code paths used during startup.
57 */
58
59 final class Resolver {
60
61 private final ModuleFinder beforeFinder;
62 private final List<Configuration> parents;
63 private final ModuleFinder afterFinder;
64 private final PrintStream traceOutput;
65
66 // maps module name to module reference
67 private final Map<String, ModuleReference> nameToReference = new HashMap<>();
68
69 // module constraints on target platform
70 private String osName;
71 private String osArch;
72 private String osVersion;
73
74 String osName() { return osName; }
75 String osArch() { return osArch; }
76 String osVersion() { return osVersion; }
77
78 /**
79 * @throws IllegalArgumentException if there are more than one parent and
80 * the constraints on the target platform conflict
81 */
82 Resolver(ModuleFinder beforeFinder,
83 List<Configuration> parents,
84 ModuleFinder afterFinder,
85 PrintStream traceOutput) {
86 this.beforeFinder = beforeFinder;
87 this.parents = parents;
88 this.afterFinder = afterFinder;
89 this.traceOutput = traceOutput;
90
91 // record constraints on target platform, checking that they don't conflict
92 for (Configuration parent : parents) {
93 String value = parent.osName();
94 if (value != null) {
95 if (osName == null) {
96 osName = value;
97 } else {
98 if (!value.equals(osName)) {
99 failParentConflict("Operating System", osName, value);
100 }
101 }
102 }
103 value = parent.osArch();
104 if (value != null) {
105 if (osArch == null) {
106 osArch = value;
107 } else {
108 if (!value.equals(osArch)) {
109 failParentConflict("OS architecture", osArch, value);
110 }
111 }
112 }
113 value = parent.osVersion();
114 if (value != null) {
115 if (osVersion == null) {
116 osVersion = value;
117 } else {
118 if (!value.equals(osVersion)) {
119 failParentConflict("OS version", osVersion, value);
120 }
121 }
122 }
123 }
124 }
125
126 private void failParentConflict(String constraint, String s1, String s2) {
127 String msg = "Parents have conflicting constraints on target "
128 + constraint + ": " + s1 + ", " + s2;
129 throw new IllegalArgumentException(msg);
130 }
131
132 /**
133 * Resolves the given named modules.
134 *
135 * @throws ResolutionException
136 */
137 Resolver resolve(Collection<String> roots) {
138
139 // create the visit stack to get us started
140 Deque<ModuleDescriptor> q = new ArrayDeque<>();
141 for (String root : roots) {
142
143 // find root module
144 ModuleReference mref = findWithBeforeFinder(root);
145 if (mref == null) {
146
147 if (findInParent(root) != null) {
148 // in parent, nothing to do
149 continue;
150 }
151
152 mref = findWithAfterFinder(root);
153 if (mref == null) {
154 findFail("Module %s not found", root);
155 }
156 }
157
158 if (isTracing()) {
159 trace("Root module %s located", root);
160 mref.location().ifPresent(uri -> trace(" (%s)", uri));
161 }
162
163 addFoundModule(mref);
164 q.push(mref.descriptor());
165 }
166
167 resolve(q);
168
169 return this;
170 }
171
172 /**
173 * Resolve all modules in the given queue. On completion the queue will be
174 * empty and any resolved modules will be added to {@code nameToReference}.
175 *
176 * @return The set of module resolved by this invocation of resolve
177 */
178 private Set<ModuleDescriptor> resolve(Deque<ModuleDescriptor> q) {
179 Set<ModuleDescriptor> resolved = new HashSet<>();
180
181 while (!q.isEmpty()) {
182 ModuleDescriptor descriptor = q.poll();
183 assert nameToReference.containsKey(descriptor.name());
184
185 // process dependences
186 for (ModuleDescriptor.Requires requires : descriptor.requires()) {
187
188 // only required at compile-time
189 if (requires.modifiers().contains(Modifier.STATIC))
190 continue;
191
192 String dn = requires.name();
193
194 // find dependence
195 ModuleReference mref = findWithBeforeFinder(dn);
196 if (mref == null) {
197
198 if (findInParent(dn) != null) {
199 // dependence is in parent
200 continue;
201 }
202
203 mref = findWithAfterFinder(dn);
204 if (mref == null) {
205 findFail("Module %s not found, required by %s",
206 dn, descriptor.name());
207 }
208 }
209
210 if (!nameToReference.containsKey(dn)) {
211 addFoundModule(mref);
212 q.offer(mref.descriptor());
213 resolved.add(mref.descriptor());
214
215 if (isTracing()) {
216 trace("Module %s located, required by %s",
217 dn, descriptor.name());
218 mref.location().ifPresent(uri -> trace(" (%s)", uri));
219 }
220 }
221
222 }
223
224 resolved.add(descriptor);
225 }
226
227 return resolved;
228 }
229
230 /**
231 * Augments the set of resolved modules with modules induced by the
232 * service-use relation.
233 */
234 Resolver bind() {
235
236 // Scan the finders for all available service provider modules. As
237 // java.base uses services then then module finders will be scanned
238 // anyway.
239 Map<String, Set<ModuleReference>> availableProviders = new HashMap<>();
240 for (ModuleReference mref : findAll()) {
241 ModuleDescriptor descriptor = mref.descriptor();
242 if (!descriptor.provides().isEmpty()) {
243
244 for (Provides provides : descriptor.provides()) {
245 String sn = provides.service();
246
247 // computeIfAbsent
248 Set<ModuleReference> providers = availableProviders.get(sn);
249 if (providers == null) {
250 providers = new HashSet<>();
251 availableProviders.put(sn, providers);
252 }
253 providers.add(mref);
254 }
255
256 }
257 }
258
259 // create the visit stack
260 Deque<ModuleDescriptor> q = new ArrayDeque<>();
261
262 // the initial set of modules that may use services
263 Set<ModuleDescriptor> initialConsumers;
264 if (Layer.boot() == null) {
265 initialConsumers = new HashSet<>();
266 } else {
267 initialConsumers = parents.stream()
268 .flatMap(Configuration::configurations)
269 .distinct()
270 .flatMap(c -> c.descriptors().stream())
271 .collect(Collectors.toSet());
272 }
273 for (ModuleReference mref : nameToReference.values()) {
274 initialConsumers.add(mref.descriptor());
275 }
276
277 // Where there is a consumer of a service then resolve all modules
278 // that provide an implementation of that service
279 Set<ModuleDescriptor> candidateConsumers = initialConsumers;
280 do {
281 for (ModuleDescriptor descriptor : candidateConsumers) {
282 if (!descriptor.uses().isEmpty()) {
283 for (String service : descriptor.uses()) {
284 Set<ModuleReference> mrefs = availableProviders.get(service);
285 if (mrefs != null) {
286 for (ModuleReference mref : mrefs) {
287 ModuleDescriptor provider = mref.descriptor();
288 if (!provider.equals(descriptor)) {
289
290 trace("Module %s provides %s, used by %s",
291 provider.name(), service, descriptor.name());
292
293 String pn = provider.name();
294 if (!nameToReference.containsKey(pn)) {
295 if (isTracing()) {
296 mref.location()
297 .ifPresent(uri -> trace(" (%s)", uri));
298 }
299 addFoundModule(mref);
300 q.push(provider);
301 }
302 }
303 }
304 }
305 }
306 }
307 }
308
309 candidateConsumers = resolve(q);
310 } while (!candidateConsumers.isEmpty());
311
312 return this;
313 }
314
315
316 /**
317 * Add the module to the nameToReference map. Also check any constraints on
318 * the target platform with the constraints of other modules.
319 */
320 private void addFoundModule(ModuleReference mref) {
321 ModuleDescriptor descriptor = mref.descriptor();
322 nameToReference.put(descriptor.name(), mref);
323
324 if (descriptor.osName().isPresent()
325 || descriptor.osArch().isPresent()
326 || descriptor.osVersion().isPresent())
327 checkTargetConstraints(descriptor);
328 }
329
330 /**
331 * Check that the module's constraints on the target platform do not
332 * conflict with the constraints of other modules resolved so far or
333 * modules in parent configurations.
334 */
335 private void checkTargetConstraints(ModuleDescriptor descriptor) {
336 String value = descriptor.osName().orElse(null);
337 if (value != null) {
338 if (osName == null) {
339 osName = value;
340 } else {
341 if (!value.equals(osName)) {
342 failTargetConstraint(descriptor);
343 }
344 }
345 }
346 value = descriptor.osArch().orElse(null);
347 if (value != null) {
348 if (osArch == null) {
349 osArch = value;
350 } else {
351 if (!value.equals(osArch)) {
352 failTargetConstraint(descriptor);
353 }
354 }
355 }
356 value = descriptor.osVersion().orElse(null);
357 if (value != null) {
358 if (osVersion == null) {
359 osVersion = value;
360 } else {
361 if (!value.equals(osVersion)) {
362 failTargetConstraint(descriptor);
363 }
364 }
365 }
366 }
367
368 private void failTargetConstraint(ModuleDescriptor md) {
369 String s1 = targetAsString(osName, osArch, osVersion);
370 String s2 = targetAsString(md);
371 findFail("Module %s has constraints on target platform that conflict" +
372 " with other modules: %s, %s", md.name(), s1, s2);
373 }
374
375 private String targetAsString(ModuleDescriptor descriptor) {
376 String osName = descriptor.osName().orElse(null);
377 String osArch = descriptor.osArch().orElse(null);
378 String osVersion = descriptor.osVersion().orElse(null);
379 return targetAsString(osName, osArch, osVersion);
380 }
381
382 private String targetAsString(String osName, String osArch, String osVersion) {
383 return new StringJoiner("-")
384 .add(Objects.toString(osName, "*"))
385 .add(Objects.toString(osArch, "*"))
386 .add(Objects.toString(osVersion, "*"))
387 .toString();
388 }
389
390
391 /**
392 * Execute post-resolution checks and returns the module graph of resolved
393 * modules as {@code Map}. The resolved modules will be in the given
394 * configuration.
395 *
396 * @param check {@true} to execute the post resolution checks
397 */
398 Map<ResolvedModule, Set<ResolvedModule>> finish(Configuration cf,
399 boolean check)
400 {
401 if (isTracing()) {
402 trace("Result:");
403 Set<String> names = nameToReference.keySet();
404 names.stream().sorted().forEach(name -> trace(" %s", name));
405 }
406
407 if (check) {
408 detectCycles();
409 checkHashes();
410 }
411
412 Map<ResolvedModule, Set<ResolvedModule>> graph = makeGraph(cf);
413
414 if (check) {
415 checkExportSuppliers(graph);
416 }
417
418 return graph;
419 }
420
421 /**
422 * Checks the given module graph for cycles.
423 *
424 * For now the implementation is a simple depth first search on the
425 * dependency graph. We'll replace this later, maybe with Tarjan.
426 */
427 private void detectCycles() {
428 visited = new HashSet<>();
429 visitPath = new LinkedHashSet<>(); // preserve insertion order
430 for (ModuleReference mref : nameToReference.values()) {
431 visit(mref.descriptor());
432 }
433 visited.clear();
434 }
435
436 // the modules that were visited
437 private Set<ModuleDescriptor> visited;
438
439 // the modules in the current visit path
440 private Set<ModuleDescriptor> visitPath;
441
442 private void visit(ModuleDescriptor descriptor) {
443 if (!visited.contains(descriptor)) {
444 boolean added = visitPath.add(descriptor);
445 if (!added) {
446 resolveFail("Cycle detected: %s", cycleAsString(descriptor));
447 }
448 for (ModuleDescriptor.Requires requires : descriptor.requires()) {
449 String dn = requires.name();
450
451 ModuleReference mref = nameToReference.get(dn);
452 if (mref != null) {
453 ModuleDescriptor other = mref.descriptor();
454 if (other != descriptor) {
455 // dependency is in this configuration
456 visit(other);
457 }
458 }
459 }
460 visitPath.remove(descriptor);
461 visited.add(descriptor);
462 }
463 }
464
465 /**
466 * Returns a String with a list of the modules in a detected cycle.
467 */
468 private String cycleAsString(ModuleDescriptor descriptor) {
469 List<ModuleDescriptor> list = new ArrayList<>(visitPath);
470 list.add(descriptor);
471 int index = list.indexOf(descriptor);
472 return list.stream()
473 .skip(index)
474 .map(ModuleDescriptor::name)
475 .collect(Collectors.joining(" -> "));
476 }
477
478
479 /**
480 * Checks the hashes in the module descriptor to ensure that they match
481 * any recorded hashes.
482 */
483 private void checkHashes() {
484 for (ModuleReference mref : nameToReference.values()) {
485
486 // get the recorded hashes, if any
487 if (!(mref instanceof ModuleReferenceImpl))
488 continue;
489 ModuleHashes hashes = ((ModuleReferenceImpl)mref).recordedHashes();
490 if (hashes == null)
491 continue;
492
493 ModuleDescriptor descriptor = mref.descriptor();
494 String algorithm = hashes.algorithm();
495 for (String dn : hashes.names()) {
496 ModuleReference mref2 = nameToReference.get(dn);
497 if (mref2 == null) {
498 ResolvedModule resolvedModule = findInParent(dn);
499 if (resolvedModule != null)
500 mref2 = resolvedModule.reference();
501 }
502 if (mref2 == null)
503 continue;
504
505 if (!(mref2 instanceof ModuleReferenceImpl)) {
506 findFail("Unable to compute the hash of module %s", dn);
507 }
508
509 // skip checking the hash if the module has been patched
510 ModuleReferenceImpl other = (ModuleReferenceImpl)mref2;
511 if (other != null && !other.isPatched()) {
512 byte[] recordedHash = hashes.hashFor(dn);
513 byte[] actualHash = other.computeHash(algorithm);
514 if (actualHash == null)
515 findFail("Unable to compute the hash of module %s", dn);
516 if (!Arrays.equals(recordedHash, actualHash)) {
517 findFail("Hash of %s (%s) differs to expected hash (%s)" +
518 " recorded in %s", dn, toHexString(actualHash),
519 toHexString(recordedHash), descriptor.name());
520 }
521 }
522 }
523
524 }
525 }
526
527 private static String toHexString(byte[] ba) {
528 StringBuilder sb = new StringBuilder(ba.length * 2);
529 for (byte b: ba) {
530 sb.append(String.format("%02x", b & 0xff));
531 }
532 return sb.toString();
533 }
534
535
536 /**
537 * Computes the readability graph for the modules in the given Configuration.
538 *
539 * The readability graph is created by propagating "requires" through the
540 * "requires transitive" edges of the module dependence graph. So if the
541 * module dependence graph has m1 requires m2 && m2 requires transitive m3
542 * then the resulting readability graph will contain m1 reads m2, m1 reads m3,
543 * and m2 reads m3.
544 */
545 private Map<ResolvedModule, Set<ResolvedModule>> makeGraph(Configuration cf) {
546
547 // initial capacity of maps to avoid resizing
548 int capacity = 1 + (4 * nameToReference.size())/ 3;
549
550 // the "reads" graph starts as a module dependence graph and
551 // is iteratively updated to be the readability graph
552 Map<ResolvedModule, Set<ResolvedModule>> g1 = new HashMap<>(capacity);
553
554 // the "requires transitive" graph, contains requires transitive edges only
555 Map<ResolvedModule, Set<ResolvedModule>> g2;
556
557 // need "requires transitive" from the modules in parent configurations
558 // as there may be selected modules that have a dependency on modules in
559 // the parent configuration.
560 if (Layer.boot() == null) {
561 g2 = new HashMap<>(capacity);
562 } else {
563 g2 = parents.stream()
564 .flatMap(Configuration::configurations)
565 .distinct()
566 .flatMap(c ->
567 c.modules().stream().flatMap(m1 ->
568 m1.descriptor().requires().stream()
569 .filter(r -> r.modifiers().contains(Modifier.TRANSITIVE))
570 .flatMap(r -> {
571 Optional<ResolvedModule> m2 = c.findModule(r.name());
572 assert m2.isPresent()
573 || r.modifiers().contains(Modifier.STATIC);
574 return m2.stream();
575 })
576 .map(m2 -> Map.entry(m1, m2))
577 )
578 )
579 // stream of m1->m2
580 .collect(Collectors.groupingBy(Map.Entry::getKey,
581 HashMap::new,
582 Collectors.mapping(Map.Entry::getValue, Collectors.toSet())
583 ));
584 }
585
586 // populate g1 and g2 with the dependences from the selected modules
587
588 Map<String, ResolvedModule> nameToResolved = new HashMap<>(capacity);
589
590 for (ModuleReference mref : nameToReference.values()) {
591 ModuleDescriptor descriptor = mref.descriptor();
592 String name = descriptor.name();
593
594 ResolvedModule m1 = computeIfAbsent(nameToResolved, name, cf, mref);
595
596 Set<ResolvedModule> reads = new HashSet<>();
597 Set<ResolvedModule> requiresTransitive = new HashSet<>();
598
599 for (ModuleDescriptor.Requires requires : descriptor.requires()) {
600 String dn = requires.name();
601
602 ResolvedModule m2 = null;
603 ModuleReference mref2 = nameToReference.get(dn);
604 if (mref2 != null) {
605 // same configuration
606 m2 = computeIfAbsent(nameToResolved, dn, cf, mref2);
607 } else {
608 // parent configuration
609 m2 = findInParent(dn);
610 if (m2 == null) {
611 assert requires.modifiers().contains(Modifier.STATIC);
612 continue;
613 }
614 }
615
616 // m1 requires m2 => m1 reads m2
617 reads.add(m2);
618
619 // m1 requires transitive m2
620 if (requires.modifiers().contains(Modifier.TRANSITIVE)) {
621 requiresTransitive.add(m2);
622 }
623
624 }
625
626 // automatic modules read all selected modules and all modules
627 // in parent configurations
628 if (descriptor.isAutomatic()) {
629
630 // reads all selected modules
631 // `requires transitive` all selected automatic modules
632 for (ModuleReference mref2 : nameToReference.values()) {
633 ModuleDescriptor descriptor2 = mref2.descriptor();
634 String name2 = descriptor2.name();
635
636 if (!name.equals(name2)) {
637 ResolvedModule m2
638 = computeIfAbsent(nameToResolved, name2, cf, mref2);
639 reads.add(m2);
640 if (descriptor2.isAutomatic())
641 requiresTransitive.add(m2);
642 }
643 }
644
645 // reads all modules in parent configurations
646 // `requires transitive` all automatic modules in parent
647 // configurations
648 for (Configuration parent : parents) {
649 parent.configurations()
650 .map(Configuration::modules)
651 .flatMap(Set::stream)
652 .forEach(m -> {
653 reads.add(m);
654 if (m.reference().descriptor().isAutomatic())
655 requiresTransitive.add(m);
656 });
657 }
658 }
659
660 g1.put(m1, reads);
661 g2.put(m1, requiresTransitive);
662 }
663
664 // Iteratively update g1 until there are no more requires transitive
665 // to propagate
666 boolean changed;
667 List<ResolvedModule> toAdd = new ArrayList<>();
668 do {
669 changed = false;
670 for (Set<ResolvedModule> m1Reads : g1.values()) {
671 for (ResolvedModule m2 : m1Reads) {
672 Set<ResolvedModule> m2RequiresTransitive = g2.get(m2);
673 if (m2RequiresTransitive != null) {
674 for (ResolvedModule m3 : m2RequiresTransitive) {
675 if (!m1Reads.contains(m3)) {
676 // m1 reads m2, m2 requires transitive m3
677 // => need to add m1 reads m3
678 toAdd.add(m3);
679 }
680 }
681 }
682 }
683 if (!toAdd.isEmpty()) {
684 m1Reads.addAll(toAdd);
685 toAdd.clear();
686 changed = true;
687 }
688 }
689 } while (changed);
690
691 return g1;
692 }
693
694 /**
695 * Equivalent to
696 * <pre>{@code
697 * map.computeIfAbsent(name, k -> new ResolvedModule(cf, mref))
698 * </pre>}
699 */
700 private ResolvedModule computeIfAbsent(Map<String, ResolvedModule> map,
701 String name,
702 Configuration cf,
703 ModuleReference mref)
704 {
705 ResolvedModule m = map.get(name);
706 if (m == null) {
707 m = new ResolvedModule(cf, mref);
708 map.put(name, m);
709 }
710 return m;
711 }
712
713
714 /**
715 * Checks the readability graph to ensure that no two modules export the
716 * same package to a module. This includes the case where module M has
717 * a local package P and M reads another module that exports P to M.
718 * Also checks the uses/provides of module M to ensure that it reads a
719 * module that exports the package of the service type to M.
720 */
721 private void checkExportSuppliers(Map<ResolvedModule, Set<ResolvedModule>> graph) {
722
723 for (Map.Entry<ResolvedModule, Set<ResolvedModule>> e : graph.entrySet()) {
724 ModuleDescriptor descriptor1 = e.getKey().descriptor();
725
726 // the map of packages that are local or exported to descriptor1
727 Map<String, ModuleDescriptor> packageToExporter = new HashMap<>();
728
729 // local packages
730 Set<String> packages = descriptor1.packages();
731 for (String pn : packages) {
732 packageToExporter.put(pn, descriptor1);
733 }
734
735 // descriptor1 reads descriptor2
736 Set<ResolvedModule> reads = e.getValue();
737 for (ResolvedModule endpoint : reads) {
738 ModuleDescriptor descriptor2 = endpoint.descriptor();
739
740 if (descriptor2.isAutomatic()) {
741 // automatic modules read self and export all packages
742 if (descriptor2 != descriptor1){
743 for (String source : descriptor2.packages()) {
744 ModuleDescriptor supplier
745 = packageToExporter.putIfAbsent(source, descriptor2);
746
747 // descriptor2 and 'supplier' export source to descriptor1
748 if (supplier != null) {
749 failTwoSuppliers(descriptor1, source, descriptor2, supplier);
750 }
751 }
752
753 }
754 } else {
755 for (ModuleDescriptor.Exports export : descriptor2.exports()) {
756 if (export.isQualified()) {
757 if (!export.targets().contains(descriptor1.name()))
758 continue;
759 }
760
761 // source is exported by descriptor2
762 String source = export.source();
763 ModuleDescriptor supplier
764 = packageToExporter.putIfAbsent(source, descriptor2);
765
766 // descriptor2 and 'supplier' export source to descriptor1
767 if (supplier != null) {
768 failTwoSuppliers(descriptor1, source, descriptor2, supplier);
769 }
770 }
771
772 }
773 }
774
775 // uses/provides checks not applicable to automatic modules
776 if (!descriptor1.isAutomatic()) {
777
778 // uses S
779 for (String service : descriptor1.uses()) {
780 String pn = packageName(service);
781 if (!packageToExporter.containsKey(pn)) {
782 resolveFail("Module %s does not read a module that exports %s",
783 descriptor1.name(), pn);
784 }
785 }
786
787 // provides S
788 for (ModuleDescriptor.Provides provides : descriptor1.provides()) {
789 String pn = packageName(provides.service());
790 if (!packageToExporter.containsKey(pn)) {
791 resolveFail("Module %s does not read a module that exports %s",
792 descriptor1.name(), pn);
793 }
794 }
795
796 }
797
798 }
799
800 }
801
802 /**
803 * Fail because a module in the configuration exports the same package to
804 * a module that reads both. This includes the case where a module M
805 * containing a package p reads another module that exports p to at least
806 * module M.
807 */
808 private void failTwoSuppliers(ModuleDescriptor descriptor,
809 String source,
810 ModuleDescriptor supplier1,
811 ModuleDescriptor supplier2) {
812
813 if (supplier2 == descriptor) {
814 ModuleDescriptor tmp = supplier1;
815 supplier1 = supplier2;
816 supplier2 = tmp;
817 }
818
819 if (supplier1 == descriptor) {
820 resolveFail("Module %s contains package %s"
821 + ", module %s exports package %s to %s",
822 descriptor.name(),
823 source,
824 supplier2.name(),
825 source,
826 descriptor.name());
827 } else {
828 resolveFail("Modules %s and %s export package %s to module %s",
829 supplier1.name(),
830 supplier2.name(),
831 source,
832 descriptor.name());
833 }
834
835 }
836
837
838 /**
839 * Find a module of the given name in the parent configurations
840 */
841 private ResolvedModule findInParent(String mn) {
842 for (Configuration parent : parents) {
843 Optional<ResolvedModule> om = parent.findModule(mn);
844 if (om.isPresent())
845 return om.get();
846 }
847 return null;
848 }
849
850
851 /**
852 * Invokes the beforeFinder to find method to find the given module.
853 */
854 private ModuleReference findWithBeforeFinder(String mn) {
855
856 return beforeFinder.find(mn).orElse(null);
857
858 }
859
860 /**
861 * Invokes the afterFinder to find method to find the given module.
862 */
863 private ModuleReference findWithAfterFinder(String mn) {
864 return afterFinder.find(mn).orElse(null);
865 }
866
867 /**
868 * Returns the set of all modules that are observable with the before
869 * and after ModuleFinders.
870 */
871 private Set<ModuleReference> findAll() {
872 Set<ModuleReference> beforeModules = beforeFinder.findAll();
873 Set<ModuleReference> afterModules = afterFinder.findAll();
874
875 if (afterModules.isEmpty())
876 return beforeModules;
877
878 if (beforeModules.isEmpty()
879 && parents.size() == 1
880 && parents.get(0) == Configuration.empty())
881 return afterModules;
882
883 Set<ModuleReference> result = new HashSet<>(beforeModules);
884 for (ModuleReference mref : afterModules) {
885 String name = mref.descriptor().name();
886 if (!beforeFinder.find(name).isPresent()
887 && findInParent(name) == null) {
888 result.add(mref);
889 }
890 }
891
892 return result;
893 }
894
895 /**
896 * Returns the package name
897 */
898 private static String packageName(String cn) {
899 int index = cn.lastIndexOf(".");
900 return (index == -1) ? "" : cn.substring(0, index);
901 }
902
903 /**
904 * Throw FindException with the given format string and arguments
905 */
906 private static void findFail(String fmt, Object ... args) {
907 String msg = String.format(fmt, args);
908 throw new FindException(msg);
909 }
910
911 /**
912 * Throw ResolutionException with the given format string and arguments
913 */
914 private static void resolveFail(String fmt, Object ... args) {
915 String msg = String.format(fmt, args);
916 throw new ResolutionException(msg);
917 }
918
919 /**
920 * Tracing support
921 */
922
923 private boolean isTracing() {
924 return traceOutput != null;
925 }
926
927 private void trace(String fmt, Object ... args) {
928 if (traceOutput != null) {
929 traceOutput.format("[Resolver] " + fmt, args);
930 traceOutput.println();
931 }
932 }
933
934 }