Wow, this is some powerful stuff! Thanks for the post James. Chad
On Fri, Dec 30, 2011 at 5:24 PM, James Snell <[email protected]> wrote: > I've been going through an updating the documentation for Abdera2 to > highlight the various new features. As part of that effort, I've been > playing around with a few of the new capabilities. One of the > particularly interesting ones is that the integration with the Guava > Libraries Function and Concurrency utilities allows applications built > with Abdera2 to leverage a variety of non-blocking mechanisms. For > instance, it's now possible to encrypt, decrypt, digitally sign and > verify signatures on Atom documents without blocking the current > thread of execution. Here's a quick example... > > First, we need to prepare the encryption provider (we use Bouncy > Castle by default) > > > KeyHelper.prepareDefaultJceProvider(); > > Now the cipher key... > String jceAlgorithmName = "AES"; > KeyGenerator keyGenerator = > KeyGenerator.getInstance(jceAlgorithmName); > keyGenerator.init(128); > SecretKey key = keyGenerator.generateKey(); > > Create the entry to be encrypted... > Abdera abdera = Abdera.getInstance(); > Entry entry = abdera.newEntry(); > entry.setId("http://example.org/foo/entry";); > entry.setUpdatedNow(); > entry.setTitle("This is an entry"); > entry.setContentAsXhtml("This <b>is</b> <i>markup</i>"); > entry.addAuthor("James"); > entry.addLink("http://www.example.org";); > > Here's where it starts to get fun... The security api has been > revamped and simplified in Abdera2... > > Security absec = new Security(abdera); > > The EncryptionOptions class is now immutable and threadsafe using the > new common factory pattern... > EncryptionOptions options = > absec.getEncryption().getDefaultEncryptionOptions() > .dataEncryptionKey(key).get(); > > Abdera2 uses the Guava Library to provide a Function object that wraps > the encryption logic, we can then in turn wrap that function with a > "Future Function", an Abdera2 concept that allows a Guava Function to > be be executed within a separate thread. All we need to do is pass in > an ExecutorService instance... > > ExecutorService exec = MoreExecutors2.getExitingExecutor(); > > Function<Document<Element>,Future<Document<Element>>> ff = > MoreFunctions.futureFunction( > absec.encryptor(options), > exec); > > Now we can call our non-blocking encryption function... > Future<Document<Element>> future = > ff.apply(entry.getDocument()); > > The Future returned by the function is an instance of the Guava > ListenableFuture interface, allowing us to attach a listener that will > wait for the completion of the encryption operation without blocking > the current thread... > > com.google.common.util.concurrent.Futures.addCallback( > (ListenableFuture<Document<Element>>) future, > new FutureCallback<Document<Element>>() { > public void onSuccess(Document<Element> result) { > try { > System.out.println("The results:"); > result.writeTo(System.out); > } catch (Throwable t) { > t.printStackTrace(); > } > } > public void onFailure(Throwable t) { > t.printStackTrace(); > } > },exec); > > And that's it... non-blocking encryption of an Atom document. There > are ways that I can compose that together with the digital signature > capability to perform signing and encrypting in a single non-blocking > operation. > > This is good stuff :-) >
