/** Creates request basing on the cache data. */
private ClassLoaderRequest createRequestFromCache(String className) {
String[] items = cache.getItemNames(className);
if (items == null || items.length == 0) return null;
List<ClassLoaderOffer> offers = new ArrayList<ClassLoaderOffer>();
for (String itemName : items) offers.add(cache.createOfferByItemName(itemName));
return new ClassLoaderRequest(className, offers.toArray(new ClassLoaderOffer[offers.size()]));
}
@Override
public void close() {
mq.close();
if (cache != null) {
cache.close();
cache = null;
}
}
/**
* Returns an input stream for reading the specified remote resource.<br>
*
* @param name the resource name
* @return an input stream for reading the resource, or {@code null} if the resource could not be
* found
*/
protected InputStream getRemoteResourceAsStream(String name) {
try {
log.fine("Trying to load resource " + name + " from the class provider.");
ClassLoaderRequest request = new ClassLoaderRequest(name);
ClassLoaderResponse response = (ClassLoaderResponse) mq.requestResponse(request, id);
ClassLoaderOffer offer = response.getAcceptedOffer();
log.fine("As a response to loading " + name + " received offer " + offer);
// If a remote resource was found, store it in the cache and return it
if (offer != null && offer.hasFiles()) {
cache.registerOffer(offer);
useOffer(null, offer);
String fileLocation = cache.getFileLocation(name, offer.getName());
// we could have got null because of wrong platform-dependent
// separator used by user. Let's try again with fixed one.
// (linux can use windows-style separators for escaping,
// therefore it's not a good idea to always replace them)
if (fileLocation == null)
fileLocation =
cache.getFileLocation(
name.replace('/', File.separatorChar).replace('\\', File.separatorChar),
offer.getName());
if (fileLocation != null) {
return new FileInputStream(fileLocation);
} else
log.warning(
"The received offer does not contain the file requested or the file could not be stored: cache returned NULL");
}
} catch (JMSException | TimeoutException e) {
throw new JCloudScaleException(e);
} catch (FileNotFoundException e) {
// Ignore
}
return null;
}
private Class<?> useOffer(String className, ClassLoaderOffer offer) {
try {
if (offer == null) {
log.severe(
"Failed to use code to resolve class " + className + " as there's no offer provided.");
return null;
}
Class<?> requestedClass = null;
// we go through all files in this offer and register them within this classloader
for (ClassLoaderFile file : offer.getFiles()) {
switch (file.getType()) {
case CLASS:
if (super.findLoadedClass(file.getName()) != null) {
log.info("Attempting to load already loaded class: " + file.getName());
continue;
}
byte[] bytecode = file.getContent();
if (bytecode
== null) // if there's no content in transmitted file, we have to get it from the
// cache.
bytecode = cache.getClassBytecode(file.getName(), offer.getName());
if (bytecode == null) {
log.severe(
"Failed to define class " + file.getName() + " from offer " + offer.getName());
continue;
}
Class<?> clazz = defineClass(file.getName(), bytecode, 0, bytecode.length);
if (clazz.getName().equals(className)) requestedClass = clazz;
break;
case JAR:
String path = cache.getFileLocation(file.getName(), offer.getName());
if (path == null) {
log.severe(
"Failed to find file " + file.getName() + " from package " + offer.getName());
continue;
}
try {
addURL(new File(path).toURI().toURL());
} catch (MalformedURLException e) {
log.severe("Exception while registering file " + path + ":" + e.toString());
continue;
}
break;
case ROFILE:
// case RWFILE:
if (!cache.deployFile(file.getName(), offer.getName()))
log.severe(
"Failed to deploy required file "
+ file.getName()
+ ". Failed to write file to disk.");
break;
default:
log.severe(
"Unexpected type of file ("
+ file.getType()
+ ") provided in the offer. skipping.");
}
}
if (className != null
&& requestedClass
== null) { // this can happen as it is possible that the required class is in the jar
byte[] bytecode = cache.getClassBytecode(className, offer.getName());
if (bytecode != null) requestedClass = defineClass(className, bytecode, 0, bytecode.length);
}
usedOffers.add(offer.getName()); // if everything is fine, we add this offer as used.
return requestedClass;
} catch (Throwable ex) {
log.severe(
"Failed to use offer "
+ (offer != null ? offer.getName() : "NULL offer ")
+ " from the cache. Removing the offer and failing...");
if (offer != null) cache.removeOfferByName(offer.getName());
throw ex;
}
}
/**
* Loads class and all additional required information from the client.
*
* @param className The name of the class to load
* @return The Class object of the required class.
*/
private Class<?> loadClassData(String className) {
long start = System.nanoTime();
try {
//
// Creating request
//
ClassLoaderRequest request = createRequestFromCache(className);
if (request == null) { // this class is not registered in cache
log.fine(
String.format(
"Class %s cannot be found in cache, requesting code from the client.", className));
request = new ClassLoaderRequest(className);
} else
log.fine(
String.format(
"Class %s exists in cache in a %s offer(s). Verifying if client has the same code.",
className, request.getOffers().length));
ClassLoaderResponse response = (ClassLoaderResponse) mq.requestResponse(request, id);
if (response == null) {
log.severe(
"Client sent null response for class " + className + ". Something is wrong out there.");
return null;
}
ClassLoaderOffer acceptedOffer = response.getAcceptedOffer();
if (acceptedOffer == null
|| (!acceptedOffer.hasFiles()
&& !acceptedOffer
.hasName())) { // client does not like the stuff we sent and did not provide
// anything instead. Shit, we're screwed.
if (request.getOffers() == null || request.getOffers().length == 0)
log.severe(
String.format(
"Client did not provide code for class %s and no cached version available.",
className));
else
log.severe(
String.format(
"Client did not provide code for class %s and did not selected cached version.",
className));
return null;
}
if (!acceptedOffer
.hasFiles()) // can't check whether the name is specified as it can be cache item update.
{ // no code from client, but offer is selected
String selectedOffer = acceptedOffer.getName();
log.fine(String.format("Client selected offer %s for class %s.", selectedOffer, className));
return useOffer(className, request.getOfferByName(selectedOffer));
} else { // client provided code.
log.fine(
String.format(
"Client provided code for class %s within %s files. saving it to cache and using it.",
className, acceptedOffer.getFiles().length));
// updating the offer
cache.registerOffer(acceptedOffer);
// merging 2 offers together and using it.(alternative would be to create offer again from
// cache, but not if NoCache is used)
ClassLoaderOffer proposedOffer = request.getOfferByName(acceptedOffer.getName());
if (proposedOffer != null) updateOfferFiles(acceptedOffer, proposedOffer.getFiles());
return useOffer(className, acceptedOffer);
}
} catch (Exception e) {
log.severe("Failed to load class " + className + ": " + e.toString());
e.printStackTrace();
return null;
} finally {
String msg =
"REMOTE CLASS LOADER: loading of "
+ className
+ " took "
+ (System.nanoTime() - start) / 1000000
+ "ms.";
log.fine(msg);
}
}
/** Ensures that all additional files that this file requires are loaded. */
private void ensureAdditionalClassesLoaded(Class<?> clazz) {
if (!cache.isClassLoadedFromCache(clazz)) return;
if (!hasFileDependencyAnnotation(clazz)) return;
// we're here if annotation is present. We have to detect if all files are loaded.
//
// getting items where this class is registered.
//
String[] items = cache.getItemNames(clazz.getName());
// finding the item that we used to instantiate this class.
String usedItem = null;
if (items != null)
for (String item : items)
if (usedOffers.contains(item)) {
usedItem = item;
break;
}
//
// checking if files for this item were loaded.
//
ClassLoaderRequest request = null;
if (usedItem != null) {
String[] classesWithFiles = cache.getClassesWithFiles(usedItem);
if (classesWithFiles != null && Arrays.asList(classesWithFiles).contains(clazz.getName()))
return; // everything is fine, we loaded all necessary stuff.
request =
new ClassLoaderRequest(
clazz.getName(), new ClassLoaderOffer[] {cache.createOfferByItemName(usedItem)});
} else {
log.info(
"Class "
+ clazz.getName()
+ " has FileDependency annotation, but we could not detect the offer that this class was taken from. Asking from the client.");
request = new ClassLoaderRequest(clazz.getName());
}
// files were not loaded. asking client for the data for our class.
// Client will have to include files.
try {
ClassLoaderResponse response = (ClassLoaderResponse) mq.requestResponse(request, id);
ClassLoaderOffer acceptedOffer = response.getAcceptedOffer();
// updating the offer
if (acceptedOffer.hasFiles()) {
cache.registerOffer(acceptedOffer);
// unpacking and using it.
// we don't need class, just files. but let's do the whole sequence...
useOffer(null, acceptedOffer);
} else
log.info(
"Trying to load missing dependent files of class "
+ clazz.getName()
+ " we received offer without files. Nothing to load.");
} catch (JMSException | TimeoutException e) {
log.severe(
"Failed to load additional files for class "
+ clazz.getName()
+ " . Exception occured: "
+ e);
return;
}
}