AspectJ Weaver 1.9.20.1 · org.aspectj.weaver.tools.cache.WeavedClassCache

Manages a cache of weaved and generated classes similar to Eclipse Equinox, except designed to operate across multiple restarts of the JVM and with one cache per classloader; allowing URLClassLoaders with the same set of URI paths to share the same cache (with the default configuration).

To enable the default configuration two system properties must be set:

   "-Daj.weaving.cache.enabled=true"
   "-Daj.weaving.cache.dir=/some/directory"

The class cache is often something that application developers or containers would like to manage, so there are a few interfaces for overriding the default behavior and performing other management functions.

CacheBacking
Provides an interface for implementing a custom backing store for the cache; The default implementation in DefaultFileCacheBacking provides a naive file-backed cache. An alternate implementation may ignore caching until signaled explicitly by the application, or only cache files for a specific duration. This class delegates the locking and synchronization requirements to the CacheBacking implementation.

CacheKeyResolver
Provides methods for creating keys from classes to be cached and for creating the "scope" of the cache itself for a given classloader and aspect list. The default implementation is provided by DefaultCacheKeyResolver but an alternate implementation may want to associate a cache with a particular application running underneath a container.

This naive cache does not normally invalidate *any* classes; the interfaces above must be used to implement more intelligent behavior. Cache invalidation problems may occur in at least three scenarios:

New aspects are added dynamically somewhere in the classloader hierarchy; affecting other classes elsewhere.
Use of declare parent in aspects to change the type hierarchy; if the cache has not invalidated the right classes in the type hierarchy aspectj may not be reconstruct the class incorrectly.
Similarly to (2), the addition of fields or methods on classes which have already been weaved and cached could have inter-type conflicts.

Field Summary

Modifier and Type	Field and Description
private final CacheBacking	backing
public static final String	CACHE_IMPL
private static final List<WeavedClassCache>	cacheRegistry
private final GeneratedCachedClassHandler	cachingClassHandler
private static CacheFactory	DEFAULT_FACTORY
private final IMessageHandler	messageHandler
private final String	name
private final CacheKeyResolver	resolver
private final CacheStatistics	stats
public static final String	WEAVED_CLASS_CACHE_ENABLED
public static final byte[]	ZERO_BYTES

Constructor Summary

Access	Constructor and Description
protected	WeavedClassCache(GeneratedClassHandler existingClassHandler, IMessageHandler messageHandler, String name, CacheBacking backing, CacheKeyResolver resolver)

Method Summary

Modifier and Type	Method and Description
public void	clear() Clear the entire cache
public static WeavedClassCache	createCache(ClassLoader classloader for this cache loader, List<String> list of aspects used by the WeavingAdapter aspects, GeneratedClassHandler the existing GeneratedClassHandler used by the weaver existingClassHandler, IMessageHandler the existing messageHandler used by the weaver messageHandler) Creates a new cache using the resolver and backing returned by the DefaultCacheFactory.
public CachedClassReference	Returns: a cache key, or null if no caching should be performed createCacheKey(String ClassName, e.g. "com.foo.Bar" className, byte[] Original byte array of the class originalBytes) Create a key for a normal weaved class
public CachedClassReference	Returns: the cache key, or null if no caching should be performed createGeneratedCacheKey(String ClassName, e.g. "com.foo.Bar" className) Created a key for a generated class
protected void	error(String message, Throwable th)
protected void	error(String message)
public CachedClassEntry	Returns: the CacheEntry, or null if no entry exists in the cache get(CachedClassReference reference to the cache entry, created through createCacheKey ref, byte[] Pre-weaving class bytes - required to ensure that cached aspects refer to an unchanged original class classBytes) Get a cache value
public static List<WeavedClassCache>	getCaches() Return a list of all WeavedClassCaches which have been initialized
public GeneratedClassHandler	getCachingClassHandler() Returns a generated class handler which wraps the handler this cache was initialized with; this handler should be used to make sure that generated classes are added to the cache
public String	getName()
public CacheStatistics	getStats() Get the statistics associated with this cache, or null if statistics have not been enabled.
public void	ignore(CachedClassReference The cache reference ref, byte[] The un-weaved class bytes classBytes) Put a cache entry to indicate that the class should not be weaved; the original bytes of the class should be used.
protected void	info(String message)
public static boolean	Returns: true if caching is enabled isEnabled() Has caching been enabled through the System property, WEAVED_CLASS_CACHE_ENABLED
public void	put(CachedClassReference reference to the entry, as created through createCacheKey ref, byte[] pre-weaving class bytes classBytes, byte[] bytes to cache weavedBytes) Put a class in the cache
public void	remove(CachedClassReference ref) Invalidate a cache entry
public static void	setDefaultCacheFactory(CacheFactory factory) The Cache and be extended in two ways, through a specialized CacheKeyResolver and a specialized CacheBacking.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

backing	back to summary
private final CacheBacking backing

CACHE_IMPL	back to summary
public static final String CACHE_IMPL

cacheRegistry	back to summary
private static final List<WeavedClassCache> cacheRegistry

cachingClassHandler	back to summary
private final GeneratedCachedClassHandler cachingClassHandler

DEFAULT_FACTORY	back to summary
private static CacheFactory DEFAULT_FACTORY

messageHandler	back to summary
private final IMessageHandler messageHandler

name	back to summary
private final String name

resolver	back to summary
private final CacheKeyResolver resolver

stats	back to summary
private final CacheStatistics stats

WEAVED_CLASS_CACHE_ENABLED	back to summary
public static final String WEAVED_CLASS_CACHE_ENABLED

ZERO_BYTES	back to summary
public static final byte[] ZERO_BYTES

Constructor Detail

WeavedClassCache	back to summary
protected WeavedClassCache(GeneratedClassHandler existingClassHandler, IMessageHandler messageHandler, String name, CacheBacking backing, CacheKeyResolver resolver)

Method Detail

clear	back to summary
public void clear() Clear the entire cache

createCache	back to summary
public static WeavedClassCache createCache(ClassLoader loader, List<String> aspects, GeneratedClassHandler existingClassHandler, IMessageHandler messageHandler) Creates a new cache using the resolver and backing returned by the DefaultCacheFactory. Parameters loader:ClassLoader classloader for this cache aspects:List<String> list of aspects used by the WeavingAdapter existingClassHandler:GeneratedClassHandler the existing GeneratedClassHandler used by the weaver messageHandler:IMessageHandler the existing messageHandler used by the weaver

createCache

back to summary

public static WeavedClassCache createCache(ClassLoader loader, List<String> aspects, GeneratedClassHandler existingClassHandler, IMessageHandler messageHandler)

Creates a new cache using the resolver and backing returned by the DefaultCacheFactory.

Parameters

loader:ClassLoader: classloader for this cache
aspects:List<String>: list of aspects used by the WeavingAdapter
existingClassHandler:GeneratedClassHandler: the existing GeneratedClassHandler used by the weaver
messageHandler:IMessageHandler: the existing messageHandler used by the weaver

createCacheKey	back to summary
public CachedClassReference createCacheKey(String className, byte[] originalBytes) Create a key for a normal weaved class Parameters className:String ClassName, e.g. "com.foo.Bar" originalBytes:byte[] Original byte array of the class Returns:CachedClassReference a cache key, or null if no caching should be performed

createCacheKey

back to summary

public CachedClassReference createCacheKey(String className, byte[] originalBytes)

Create a key for a normal weaved class

Parameters

className:String: ClassName, e.g. "com.foo.Bar"
originalBytes:byte[]: Original byte array of the class

Returns:CachedClassReference

a cache key, or null if no caching should be performed

createGeneratedCacheKey	back to summary
public CachedClassReference createGeneratedCacheKey(String className) Created a key for a generated class Parameters className:String ClassName, e.g. "com.foo.Bar" Returns:CachedClassReference the cache key, or null if no caching should be performed

createGeneratedCacheKey

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public CachedClassReference createGeneratedCacheKey(String className)

Created a key for a generated class

Parameters

className:String: ClassName, e.g. "com.foo.Bar"

Returns:CachedClassReference

the cache key, or null if no caching should be performed

error	back to summary
protected void error(String message, Throwable th)

error	back to summary
protected void error(String message)

get	back to summary
public CachedClassEntry get(CachedClassReference ref, byte[] classBytes) Get a cache value Parameters ref:CachedClassReference reference to the cache entry, created through createCacheKey classBytes:byte[] Pre-weaving class bytes - required to ensure that cached aspects refer to an unchanged original class Returns:CachedClassEntry the CacheEntry, or null if no entry exists in the cache

get

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

Get a cache value

Parameters

ref:CachedClassReference: reference to the cache entry, created through createCacheKey
classBytes:byte[]: Pre-weaving class bytes - required to ensure that cached aspects refer to an unchanged original class

Returns:CachedClassEntry

the CacheEntry, or null if no entry exists in the cache

getCaches	back to summary
public static List<WeavedClassCache> getCaches() Return a list of all WeavedClassCaches which have been initialized

getCachingClassHandler	back to summary
public GeneratedClassHandler getCachingClassHandler() Returns a generated class handler which wraps the handler this cache was initialized with; this handler should be used to make sure that generated classes are added to the cache

getName	back to summary
public String getName()

getStats	back to summary
public CacheStatistics getStats() Get the statistics associated with this cache, or null if statistics have not been enabled.

ignore	back to summary
public void ignore(CachedClassReference ref, byte[] classBytes) Put a cache entry to indicate that the class should not be weaved; the original bytes of the class should be used. Parameters ref:CachedClassReference The cache reference classBytes:byte[] The un-weaved class bytes

ignore

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public void ignore(CachedClassReference ref, byte[] classBytes)

Put a cache entry to indicate that the class should not be weaved; the original bytes of the class should be used.

Parameters

ref:CachedClassReference: The cache reference
classBytes:byte[]: The un-weaved class bytes

info	back to summary
protected void info(String message)

isEnabled	back to summary
public static boolean isEnabled() Has caching been enabled through the System property, WEAVED_CLASS_CACHE_ENABLED Returns:boolean true if caching is enabled

isEnabled

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public static boolean isEnabled()

Has caching been enabled through the System property, WEAVED_CLASS_CACHE_ENABLED

Returns:boolean: true if caching is enabled

put	back to summary
public void put(CachedClassReference ref, byte[] classBytes, byte[] weavedBytes) Put a class in the cache Parameters ref:CachedClassReference reference to the entry, as created through createCacheKey classBytes:byte[] pre-weaving class bytes weavedBytes:byte[] bytes to cache

put

back to summary

public void put(CachedClassReference ref, byte[] classBytes, byte[] weavedBytes)

Put a class in the cache

Parameters

ref:CachedClassReference: reference to the entry, as created through createCacheKey
classBytes:byte[]: pre-weaving class bytes
weavedBytes:byte[]: bytes to cache

remove	back to summary
public void remove(CachedClassReference ref) Invalidate a cache entry

setDefaultCacheFactory	back to summary
public static void setDefaultCacheFactory(CacheFactory factory) The Cache and be extended in two ways, through a specialized CacheKeyResolver and a specialized CacheBacking. The default factory used to create these classes can be set with this method. Since each weaver will create a cache, this method must be called before the weaver is first initialized.

public Class WeavedClassCache

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Method Summary

Field Detail

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Method Detail