Alan, thank you very much for your help. This is what I was looking for.
Only one moment - as I understand the ModuleFinder that you implemented can
work only with .war modules. However, at one JPMS layer I want to place .war
modules and .jar modules. What should I do in such situation? Should I do
ModuleFinder commonFinder = ModuleFinder.compose(jarFinder, warFinder);
Configuration cf = boot.configuration().resolve(commonFinder,
ModuleFinder.of(), Set.of(jars+wars)); ?
Best regards, Pavel
>Пятница, 28 сентября 2018, 16:52 +03:00 от Alan Bateman
><alan.bate...@oracle.com>:
>
>On 28/09/2018 13:10, Alex Sviridov wrote:
>> Hi Alan
>>
>> Thank you for your answer. But my main problem is not jars inside .war
>> - this is a so far from my current problem. Now I need to 1) add .war
>> file to layer 2). to map file location, for example instead of
>> "module-info.java" I must find "WEB-INF/classes/module-info.java" etc.
>> That is all I need. How can I do it without implementing ModuleFinder?
>You'll need a ModuleFinder because the packaging formats that
>ModuleFinder.of(Path) is required to support doesn't know anything about
>WAR files. It's not super difficult to develop your own. I attach a
>simple implementation that may get you started. It's really basic but
>would need a few iterations to be robust. Invoke
>WarModuleFinder.of(Path) with the file path to the WAR file and it will
>create a ModuleFinder that can find the application module in the WAR
>file. A more complete implementation would be a lot more robust and
>polished that this sample, it would also find the modules WEB-INF/lib.
>
>Once you have a ModuleFinder then you specify it to Conguration::resolve
>method when resolving the application as the root module. You'll
>probably start with something like:
>
> Path war = Path.of("app.war");
> ModuleFinder finder = WarModuleFinder.of(war);
>
> String appModuleName = finder.findAll().stream()
> .findFirst()
> .map(ModuleReference::descriptor)
> .map(ModuleDescriptor::name)
> .orElseThrow();
>
> ModuleLayer boot = ModuleLayer.boot();
> Configuration cf = boot.configuration().resolve(finder,
>ModuleFinder.of(), Set.of(appModuleName));
> ModuleLayer layer = boot.defineModulesWithOneLoader(cf,
>ClassLoader.getSystemClassLoader());
>
>and now you have a module layer with the application module loaded from
>the WEB-INF/classes part of the WAR file.
>
>-Alan
>
>
> static class WarModuleFinder implements ModuleFinder {
> private final FileSystem warfs;
> private final Path classes;
> private final ModuleReference mref;
>
> private WarModuleFinder(Path warfile) throws IOException {
> ClassLoader scl = ClassLoader.getSystemClassLoader();
> FileSystem fs = FileSystems.newFileSystem(warfile, scl);
> Path classes = fs.getPath("/WEB-INF/classes");
>
> ModuleDescriptor descriptor;
> try (InputStream in =
>Files.newInputStream(classes.resolve("module-info.class"))) {
> descriptor = ModuleDescriptor.read(in, () ->
>packages(classes));
> }
>
> this.warfs = fs;
> this.classes = classes;
> this.mref = new ModuleReference(descriptor, classes.toUri()) {
> @Override
> public ModuleReader open() {
> return new WarModuleReader();
> }
> public String toString() {
> StringBuilder sb = new StringBuilder();
> sb.append("[module ");
> sb.append(descriptor().name());
> sb.append(", location=");
> sb.append(location());
> sb.append("]");
> return sb.toString();
> }
> };
> }
>
> static WarModuleFinder of(Path war) throws IOException {
> return new WarModuleFinder(war);
> }
>
> @Override
> public Optional<ModuleReference> find(String name) {
> if (name.equals(mref.descriptor().name())) {
> return Optional.of(mref);
> } else {
> return Optional.empty();
> }
> }
>
> @Override
> public Set<ModuleReference> findAll() {
> return Set.of(mref);
> }
>
> private Set<String> packages(Path classes) {
> try {
> return Files.find(classes, Integer.MAX_VALUE,
> (path, attrs) -> !attrs.isDirectory())
> .map(entry -> classes.relativize(entry).toString())
> .map(this::toPackageName)
> .flatMap(Optional::stream)
> .collect(Collectors.toSet());
> } catch (IOException ioe) {
> throw new UncheckedIOException(ioe);
> }
> }
>
> private Optional<String> toPackageName(String name) {
> int index = name.lastIndexOf("/");
> if (index > 0) {
> return Optional.of(name.substring(0,
>index).replace('/', '.'));
> } else {
> return Optional.empty();
> }
> }
>
> class WarModuleReader implements ModuleReader {
> private volatile boolean closed;
>
> private void ensureOpen() throws IOException {
> if (closed) throw new IOException("ModuleReader is
>closed");
> }
>
> public Optional<URI> find(String name) throws IOException {
> ensureOpen();
> if (!name.startsWith("/")) {
> Path entry = classes.resolve(name);
> if (Files.exists(entry)) {
> return Optional.of(entry.toUri());
> }
> }
> return Optional.empty();
> }
>
> public Stream<String> list() throws IOException {
> ensureOpen();
> return Files.walk(classes)
> .map(entry -> classes.relativize(entry).toString())
> .filter(name -> name.length() > 0);
> }
>
> public void close() {
> closed = true;
> }
> }
> }
>
--
Alex Sviridov
