Class AsynchronousFileCacheBacking

java.lang.Object

org.aspectj.weaver.tools.cache.AbstractCacheBacking

org.aspectj.weaver.tools.cache.AbstractFileCacheBacking

org.aspectj.weaver.tools.cache.AbstractIndexedFileCacheBacking

org.aspectj.weaver.tools.cache.AsynchronousFileCacheBacking

All Implemented Interfaces:

CacheBacking

Direct Known Subclasses:

FlatFileCacheBacking, ZippedFileCacheBacking

public abstract class AsynchronousFileCacheBacking
extends AbstractIndexedFileCacheBacking

Uses a background thread to do the actual I/O and for caching "persistence" so that the caching works faster on repeated activations of the application. The class maintains an in-memory cache, and uses a queue of AsynchronousFileCacheBacking.AsyncCommands to signal to a background thread various actions required to "synchronize" the in-memory cache with the persisted copy. Whenever there is a cache miss from the get(CachedClassReference, byte[]) call, the weaver issues a put(CachedClassEntry, byte[]) call. This call has 2 side-effects:

• The in-memory cache is updated so that subsequent calls to get(CachedClassReference, byte[]) will not return the mapped value.
• An "update index" AsynchronousFileCacheBacking.AsyncCommand is posted to the background thread so that the newly mapped value will be persisted (eventually)

The actual persistence is implemented by the concrete classes

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	AsynchronousFileCacheBacking.AbstractCommand
static interface	AsynchronousFileCacheBacking.AsyncCommand	Represents an asynchronous command that can be sent to the AsynchronousFileCacheBacking instance to be executed on it asynchronously
static interface	AsynchronousFileCacheBacking.AsynchronousFileCacheBackingCreator<T extends AsynchronousFileCacheBacking>
static class	AsynchronousFileCacheBacking.ClearCommand
static class	AsynchronousFileCacheBacking.InsertCommand
static class	AsynchronousFileCacheBacking.KeyedCommand	Base class for AsynchronousFileCacheBacking.AbstractCommands that refer to a cache key
static class	AsynchronousFileCacheBacking.RemoveCommand
static class	AsynchronousFileCacheBacking.UpdateIndexCommand

Nested classes/interfaces inherited from class AbstractIndexedFileCacheBacking

AbstractIndexedFileCacheBacking.IndexEntry

Field Summary

Fields

Modifier and Type	Field	Description
protected final Map<String,byte[]>	bytesMap
protected final Map<String,byte[]>	exposedBytes
protected final Map<String, AbstractIndexedFileCacheBacking.IndexEntry>	exposedIndex
protected final Map<String, AbstractIndexedFileCacheBacking.IndexEntry>	index

Fields inherited from class AbstractIndexedFileCacheBacking

EMPTY_INDEX, EMPTY_KEYS, INDEX_FILE

Fields inherited from class AbstractFileCacheBacking

WEAVED_CLASS_CACHE_DIR

Fields inherited from class AbstractCacheBacking

logger

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AsynchronousFileCacheBacking(File cacheDir)

Method Summary

Modifier and Type	Method	Description
void	clear()	Clear the entire cache
protected static final <T extends AsynchronousFileCacheBacking> T	createBacking(File cacheDir, AsynchronousFileCacheBacking.AsynchronousFileCacheBackingCreator<T> creator)
protected void	executeClearCommand()
protected void	executeCommand(AsynchronousFileCacheBacking.AsyncCommand cmd)
protected void	executeInsertCommand(AsynchronousFileCacheBacking.InsertCommand cmd)
protected void	executeRemoveCommand(AsynchronousFileCacheBacking.RemoveCommand cmd)
protected void	executeUpdateIndexCommand()
CachedClassEntry	get(CachedClassReference ref, byte[] originalBytes)	Get a cache entry
Map<String,byte[]>	getBytesMap()
protected Map<String, AbstractIndexedFileCacheBacking.IndexEntry>	getIndex()
List<AbstractIndexedFileCacheBacking.IndexEntry>	getIndexEntries()
Map<String, AbstractIndexedFileCacheBacking.IndexEntry>	getIndexMap()
static final boolean	postCacheCommand(AsynchronousFileCacheBacking.AsyncCommand cmd)
void	put(CachedClassEntry entry, byte[] originalBytes)	Put an entry in the cache
protected abstract Map<String,byte[]>	readClassBytes(Map<String, AbstractIndexedFileCacheBacking.IndexEntry> indexMap, File cacheDir)
protected AbstractIndexedFileCacheBacking.IndexEntry	remove(String key)
void	remove(CachedClassReference ref)	Remove an entry from the cache
protected abstract void	removeClassBytes(String key)	Helper for executeRemoveCommand(RemoveCommand)
String	toString()

Methods inherited from class AbstractIndexedFileCacheBacking

createIndexEntry, getIndexFile, getKeys, readIndex, readIndex, readIndex, resolveIndexMapEntry, writeIndex, writeIndex, writeIndex, writeIndex, writeIndex

Methods inherited from class AbstractFileCacheBacking

close, close, delete, getCacheDirectory, writeClassBytes

Methods inherited from class AbstractCacheBacking

crc

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

index

protected final Map<String, AbstractIndexedFileCacheBacking.IndexEntry> index

exposedIndex

protected final Map<String, AbstractIndexedFileCacheBacking.IndexEntry> exposedIndex

bytesMap

protected final Map<String,byte[]> bytesMap

exposedBytes

protected final Map<String,byte[]> exposedBytes

Constructor Details

AsynchronousFileCacheBacking

protected AsynchronousFileCacheBacking(File cacheDir)

Method Details

getIndex

protected Map<String, AbstractIndexedFileCacheBacking.IndexEntry> getIndex()

Specified by:

getIndex in class AbstractIndexedFileCacheBacking

get

public CachedClassEntry get(CachedClassReference ref,
 byte[] originalBytes)

Description copied from interface: CacheBacking

Get a cache entry

Parameters:

ref - entry to retrieve

originalBytes - Pre-weaving class bytes - required in order to ensure that the cached entry refers to the same original class

Returns:

the cached bytes or null, if the entry does not exist

put

public void put(CachedClassEntry entry,
 byte[] originalBytes)

Description copied from interface: CacheBacking

Put an entry in the cache

Parameters:

entry - key of the entry

originalBytes - Pre-weaving class bytes - required in order to ensure that the cached entry refers to the same original class

remove

public void remove(CachedClassReference ref)

Description copied from interface: CacheBacking

Remove an entry from the cache

Parameters:

ref -

remove

protected AbstractIndexedFileCacheBacking.IndexEntry remove(String key)

getIndexEntries

public List<AbstractIndexedFileCacheBacking.IndexEntry> getIndexEntries()

getIndexMap

public Map<String, AbstractIndexedFileCacheBacking.IndexEntry> getIndexMap()

getBytesMap

public Map<String,byte[]> getBytesMap()

clear

public void clear()

Description copied from interface: CacheBacking

Clear the entire cache

executeCommand

protected void executeCommand(AsynchronousFileCacheBacking.AsyncCommand cmd)
                       throws Exception

Throws:

Exception

executeClearCommand

protected void executeClearCommand()
                            throws Exception

Throws:

Exception

executeUpdateIndexCommand

protected void executeUpdateIndexCommand()
                                  throws Exception

Throws:

Exception

executeInsertCommand

protected void executeInsertCommand(AsynchronousFileCacheBacking.InsertCommand cmd)
                             throws Exception

Throws:

Exception

executeRemoveCommand

protected void executeRemoveCommand(AsynchronousFileCacheBacking.RemoveCommand cmd)
                             throws Exception

Throws:

Exception

removeClassBytes

protected abstract void removeClassBytes(String key)
                                  throws Exception

Helper for executeRemoveCommand(RemoveCommand)

Parameters:

key - The key representing the class whose bytes are to be removed

Throws:

Exception - if failed to remove class bytes

readClassBytes

protected abstract Map<String,byte[]> readClassBytes(Map<String, AbstractIndexedFileCacheBacking.IndexEntry> indexMap,
 File cacheDir)

toString

public String toString()

Overrides:

toString in class Object

createBacking

protected static final <T extends AsynchronousFileCacheBacking>
T createBacking(File cacheDir,
 AsynchronousFileCacheBacking.AsynchronousFileCacheBackingCreator<T> creator)

postCacheCommand

public static final boolean postCacheCommand(AsynchronousFileCacheBacking.AsyncCommand cmd)