8.3. Existing Implementations

Apart from files, directories (FileHandler) and zip archives (ZipEntryHandler) the Microcontainer also supports other more advanced use cases. The first one is Assembled, which is similar to what Eclipse calls Linked Resources. Its purpose is to take existing resources from different trees, and "mock" them into single resource tree.

Example 8.6. Implementation of Assembled VirtualFileHandlers

AssembledDirectory sar = AssembledContextFactory.getInstance().create("assembled.sar");

URL url = getResource("/vfs/test/jar1.jar");
VirtualFile jar1 = VFS.getRoot(url);
sar.addChild(jar1);

url = getResource("/tmp/app/ext.jar");
VirtualFile ext1 = VFS.getRoot(url);
sar.addChild(ext);

AssembledDirectory metainf = sar.mkdir("META-INF");

url = getResource("/config/jboss-service.xml");
VirtualFile serviceVF = VFS.getRoot(url);
metainf.addChild(serviceVF);

AssembledDirectory app = sar.mkdir("app.jar");
url = getResource("/app/someapp/classes");
VirtualFile appVF = VFS.getRoot(url);
app.addPath(appVF, new SuffixFilter(".class"));
Another implementation is in-memory files. This implementation arose out of a need to easily handle AOP generated bytes. Instead of using temporary files, you can drop bytes into in-memory VirtualFileHandlers.

Example 8.7. Implementation of In-Memory VirtualFileHandlers

URL url = new URL("vfsmemory://aopdomain/org/acme/test/Test.class");
byte[] bytes = ...; // some AOP generated class bytes
MemoryFileFactory.putFile(url,  bytes);

VirtualFile classFile = VFS.getVirtualFile(new URL("vfsmemory://aopdomain"), "org/acme/test/Test.class");
InputStream bis = classFile.openStream(); // e.g. load class from input stream