fabric.dissemination

Class Cache

java.lang.Object

fabric.dissemination.Cache

public class Cache
extends java.lang.Object

The cache object used by the disseminator to store globs. Essentially a hashtable specialized for globs; it also fetches globs directly from stores when needed.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Cache.Entry

Constructor Summary

Constructors

Constructor and Description
Cache()

Method Summary

Modifier and Type	Method and Description
Cache.Entry	get(RemoteStore store, long onum) Retrieves a glob from the cache, without trying to fetch it from the store.
Cache.Entry	get(RemoteStore store, long onum, boolean fetch) Retrieves a glob from the cache or fetches it from the store.
void	put(RemoteStore store, long onum, ObjectGlob g) Put given glob into the cache.
java.util.List<Pair<Pair<RemoteStore,java.lang.Long>,java.lang.Long>>	sortedTimestamps() Returns a snapshot set of the timestamp for each OID currently in the cache.
java.util.Set<Pair<Pair<RemoteStore,java.lang.Long>,java.lang.Long>>	timestamps() Returns a snapshot of the timestamp for each OID currently in the cache.
boolean	updateEntry(RemoteStore store, long onum, ObjectGlob g) Updates the dissemination and worker cache with the given object glob.

Methods inherited from class java.lang.Object

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

Constructor Detail

Cache

public Cache()

Method Detail

get

public Cache.Entry get(RemoteStore store,
                       long onum)

Retrieves a glob from the cache, without trying to fetch it from the store.

Parameters:

store - the store of the object to retrieve.

onum - the onum of the object.

Returns:

the glob, if it is in the cache; null otherwise.

get

public Cache.Entry get(RemoteStore store,
                       long onum,
                       boolean fetch)

Retrieves a glob from the cache or fetches it from the store.

Parameters:

store - the store of the object to retrieve.

onum - the onum of the object.

fetch - whether the glob should be should fetched from store in the event of a cache miss.

Returns:

the glob, or null if fetch is false and glob does not exists in cache.

put

public void put(RemoteStore store,
                long onum,
                ObjectGlob g)

Put given glob into the cache.

Parameters:

store - the store of the object.

onum - the onum of the object.

g - the glob.

updateEntry

public boolean updateEntry(RemoteStore store,
                           long onum,
                           ObjectGlob g)

Updates the dissemination and worker cache with the given object glob. If the caches do not have entries for the given glob, then nothing is changed.

Returns:

true iff either of the caches was changed.

timestamps

public java.util.Set<Pair<Pair<RemoteStore,java.lang.Long>,java.lang.Long>> timestamps()

Returns a snapshot of the timestamp for each OID currently in the cache. This set is NOT backed by the underlying map. If new keys are inserted or removed from the cache, they will not be reflected by the set returned. However, no synchronization is needed for working with the set.

sortedTimestamps

public java.util.List<Pair<Pair<RemoteStore,java.lang.Long>,java.lang.Long>> sortedTimestamps()

Returns a snapshot set of the timestamp for each OID currently in the cache. The set is sorted in descending order by the popularity of the corresponding objects. Like timestamps(), the returned set is not backed by the underlying table.