IBM WebSphere Application ServerTM
Release 8

com.ibm.wsspi.cache
Class Cache

java.lang.Object
  extended by com.ibm.wsspi.cache.Cache

public class Cache
extends java.lang.Object

This is the underlying cache mechanism that is used by the CacheMonitor. It contains the methods used to inspect and manage the current state of the cache.


Constructor Summary
Cache(com.ibm.websphere.cache.Cache ci)
           
 
Method Summary
 void clear()
          This method clears everything from the cache, so that it is just like when it was instantiated.
 void clearDisk()
          This method clears everything from the disk cache.
 java.util.Collection getAllDependencyIds()
          This method returns the dependency IDs for all cache entries in the memory cache.
 java.util.Enumeration getAllIds()
          This method returns the cache IDs for all cache entries from memory cache.
 java.util.Collection getCacheIdsByDependency(java.lang.String dependency)
          This method returns the cache IDs of the entries in the memory cache specified by the dependency ID.
 java.util.Collection getCacheIdsByTemplate(java.lang.String template)
          This method returns the cache IDs of the entries in the memory cache specified by the template.
 CacheStatisticsListener getCacheStatisticsListener()
          This method returns an instance of CacheStatisticsListener.
 long getCleanupFrequency()
          This method returns a value for the disk cache cleanup frequency, in minutes.
 int getDefaultPriority()
          This method returns the default priority value as set in the Administrator console GUI/dynacache.xml file.
 boolean getDelayOffload()
          This method returns a boolean to indicate whether the disk cache is using buffers for dependency IDs and templates.
 long getDelayOffloadDepIdBuckets()
          This method returns a value for the maximum number of dependency identifier buckets in the disk cache metadata in memory.
 long getDelayOffloadEntriesLimit()
          This method returns a value for the maximum number of cache identifiers that are stored for an individual dependency ID or template in the disk cache metadata in memory.
 long getDelayOffloadTemplateBuckets()
          This method returns a value for the maximum number of template buckets in the disk cache metadata in memory.
 java.util.Collection getDepIdsByRangeDisk(int index, int length)
          This method returns the dependency IDs found in the disk cache based on specified the index and the length.
 int getDepIdsSizeDisk()
          This method returns the current number of dependency IDs in the disk cache.
 java.util.Collection getDepIdValueDisk(java.lang.Object depId)
          This method returns the cache IDs of the entries in the disk cache specified by the dependency ID.
 long getDiskCacheEntrySizeInMBLimit()
          This method returns the maximum size of an individual cache entry in megabytes (MB).
 int getDiskCacheEvictionPolicy()
          This method returns the eviction algorithm that the disk cache will use to evict entries once the high threshold is reached.
 int getDiskCacheHighThreshold()
          This method returns the high threshold is expressed in terms of the percentage of the disk cache size in GB or entries.
 int getDiskCacheLowThreshold()
          This method returns the low threshold is expressed in terms of the percentage of the disk cache size in GB or entries.
 int getDiskCachePerformanceLevel()
          This method returns the performance level to tune the performance of the disk cache.
 long getDiskCacheSizeInGBLimit()
          This method returns the maximum number of disk cache size in gigabytes (GB).
 float getDiskCacheSizeInMBs()
          This method returns the current disk cache size in Megabytes (MB).
 long getDiskCacheSizeLimit()
          This method returns the maximum number of cache entries that are held in disk cache.
 CacheEntry getEntry(java.lang.Object cacheId)
          This method returns an instance of CacheEntry specified cache ID.
 CacheEntry getEntryDisk(java.lang.Object cacheId)
          This method returns the cache entry specified by cache ID from the disk cache.
 boolean getFlushToDiskOnStop()
          This method returns a boolean to indicate whether in-memory cached objects are saved to disk when the server stops.
 java.util.Collection getIdsByRangeDisk(int index, int length)
          This method returns the cache IDs found in the disk cache based on specified the index and the length.
 int getIdsSizeDisk()
          This method returns the current number of cache entries in the disk cache.
 int getMaxCacheSizeInMB()
          This method returns the maximum space on the JVM heap that can be occupied by the cache entries.
 int getMaxNumberCacheEntries()
          This method returns the maximum number of cache entries that are held in memory cache.
 float getMemoryCacheSizeInMB()
          This method returns the current space on the JVM heap that is occupied by the cache entries.
 int getNumberCacheEntries()
          This method returns the current number of cache entries for this cache instance.
 boolean getSwapToDisk()
          This method determines the disk offloaded feature is enabled or not.
 java.util.Collection getTemplatesByRangeDisk(int index, int length)
          This method returns the templates found in the disk cache based on specified the index and the length.
 int getTemplatesSizeDisk()
          This method returns the current number of templates in the disk cache.
 java.util.Collection getTemplateValueDisk(java.lang.String template)
          This method returns the cache IDs of the entries in the disk cache specified by the template.
 void invalidateById(java.lang.String id, boolean waitOnInvalidation)
          This method invalidates in all caches all entries dependent on the specified id.
 void invalidateByTemplate(java.lang.String template, boolean waitOnInvalidation)
          This method invalidates in all caches all entries dependent on the specified template.
 void refreshEntry(CacheEntry ce)
          This method moves the specified entry to the end of the LRU queue.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

Cache

public Cache(com.ibm.websphere.cache.Cache ci)
Method Detail

refreshEntry

public void refreshEntry(CacheEntry ce)
This method moves the specified entry to the end of the LRU queue.

Parameters:
ce - The cache entry

getSwapToDisk

public boolean getSwapToDisk()
This method determines the disk offloaded feature is enabled or not.

Returns:
True if disk offload feature is enabled. False if disk offload is disabled.

getEntryDisk

public CacheEntry getEntryDisk(java.lang.Object cacheId)
This method returns the cache entry specified by cache ID from the disk cache.

Parameters:
cacheId - the cache ID
Returns:
The cache entry. NULL if cache ID does not exist.

clearDisk

public void clearDisk()
This method clears everything from the disk cache.


getIdsByRangeDisk

public java.util.Collection getIdsByRangeDisk(int index,
                                              int length)
This method returns the cache IDs found in the disk cache based on specified the index and the length. If index = 1 or -1, the set might contain "DISKCACHE_MORE" to indicate there are more cache IDs in the disk cache. The caller need to remove DISKCACHE_MORE" from the set before it is being used.

Parameters:
index - If index = 0, it starts the beginning. If index = 1, it means "next". If Index = -1, it means "previous".
length - The max number of cache IDs to be read. If length = -1, it reads all cache IDs until the end.
Returns:
The collecton of cache IDs.

getTemplatesByRangeDisk

public java.util.Collection getTemplatesByRangeDisk(int index,
                                                    int length)
This method returns the templates found in the disk cache based on specified the index and the length. If index = 1 or -1, the set might contain "DISKCACHE_MORE" to indicate there are more templates in the disk cache. The caller need to remove DISKCACHE_MORE" from the set before it is being used.

Parameters:
index - If index = 0, it starts the beginning. If index = 1, it means "next". If Index = -1, it means "previous".
length - The max number of templates to be read. If length = -1, it reads all templates until the end.
Returns:
The collecton of templates.

getCacheStatisticsListener

public CacheStatisticsListener getCacheStatisticsListener()
This method returns an instance of CacheStatisticsListener.

Returns:
The instance of CacheStatisticsListener

getEntry

public CacheEntry getEntry(java.lang.Object cacheId)
This method returns an instance of CacheEntry specified cache ID.

Parameters:
cacheId - the cache ID
Returns:
The instance of CacheEntry

invalidateById

public void invalidateById(java.lang.String id,
                           boolean waitOnInvalidation)
This method invalidates in all caches all entries dependent on the specified id.

Parameters:
id - The cache id or data id.
waitOnInvalidation - True indicates that this method should not return until the invalidations have taken effect on all caches. False indicates that the invalidations will be queued for later batch processing.

invalidateByTemplate

public void invalidateByTemplate(java.lang.String template,
                                 boolean waitOnInvalidation)
This method invalidates in all caches all entries dependent on the specified template.

Parameters:
template - The template name.
waitOnInvalidation - True indicates that this method should not return until the invalidations have taken effect on all caches. False indicates that the invalidations will be queued for later batch processing.

clear

public void clear()
This method clears everything from the cache, so that it is just like when it was instantiated.


getAllIds

public java.util.Enumeration getAllIds()
This method returns the cache IDs for all cache entries from memory cache.

Returns:
The Enumeration of cache ids.

getMaxNumberCacheEntries

public int getMaxNumberCacheEntries()
This method returns the maximum number of cache entries that are held in memory cache.

Returns:
The maximum of cache entries.

getNumberCacheEntries

public int getNumberCacheEntries()
This method returns the current number of cache entries for this cache instance.

Returns:
The current number of cache entries.

getMaxCacheSizeInMB

public int getMaxCacheSizeInMB()
This method returns the maximum space on the JVM heap that can be occupied by the cache entries.

Returns:
The maximum size of cache allowed in terms of JVM heap.

getMemoryCacheSizeInMB

public float getMemoryCacheSizeInMB()
This method returns the current space on the JVM heap that is occupied by the cache entries.

Returns:
The current size of cache in terms of JVM heap.

getDefaultPriority

public int getDefaultPriority()
This method returns the default priority value as set in the Administrator console GUI/dynacache.xml file.

Returns:
The default priority

getAllDependencyIds

public java.util.Collection getAllDependencyIds()
This method returns the dependency IDs for all cache entries in the memory cache.

Returns:
A Collection of dependency IDs.

getCacheIdsByDependency

public java.util.Collection getCacheIdsByDependency(java.lang.String dependency)
This method returns the cache IDs of the entries in the memory cache specified by the dependency ID.

Parameters:
dependency - ID for the group of cache IDs.
Returns:
A Collection of cache IDs

getCacheIdsByTemplate

public java.util.Collection getCacheIdsByTemplate(java.lang.String template)
This method returns the cache IDs of the entries in the memory cache specified by the template.

Parameters:
template - for the group of cache IDs.
Returns:
A Collection of cache IDs

getTemplatesSizeDisk

public int getTemplatesSizeDisk()
This method returns the current number of templates in the disk cache.

Returns:
The current number of templates

getTemplateValueDisk

public java.util.Collection getTemplateValueDisk(java.lang.String template)
This method returns the cache IDs of the entries in the disk cache specified by the template.

Parameters:
template - for the group of cache IDs.
Returns:
A Collection of cache IDs

getIdsSizeDisk

public int getIdsSizeDisk()
This method returns the current number of cache entries in the disk cache.

Returns:
The current number of cache entries

getDepIdsSizeDisk

public int getDepIdsSizeDisk()
This method returns the current number of dependency IDs in the disk cache.

Returns:
The current number of dependency IDs

getDepIdsByRangeDisk

public java.util.Collection getDepIdsByRangeDisk(int index,
                                                 int length)
This method returns the dependency IDs found in the disk cache based on specified the index and the length. If index = 1 or -1, the set might contain "DISKCACHE_MORE" to indicate there are more dependency IDs in the disk cache. The caller need to remove DISKCACHE_MORE" from the set before it is being used.

Parameters:
index - If index = 0, it starts the beginning. If index = 1, it means "next". If Index = -1, it means "previous".
length - The max number of dependency IDs to be read. If length = -1, it reads all dependency IDs until the end.
Returns:
The collecton of dependency IDs.

getDepIdValueDisk

public java.util.Collection getDepIdValueDisk(java.lang.Object depId)
This method returns the cache IDs of the entries in the disk cache specified by the dependency ID.

Parameters:
depId - for the group of cache IDs.
Returns:
A Collection of cache IDs

getDiskCacheSizeLimit

public long getDiskCacheSizeLimit()
This method returns the maximum number of cache entries that are held in disk cache.

Returns:
The maximum of disk cache entries.

getDiskCacheSizeInGBLimit

public long getDiskCacheSizeInGBLimit()
This method returns the maximum number of disk cache size in gigabytes (GB).

Returns:
The maximum of disk cache size in GB.

getDiskCacheEntrySizeInMBLimit

public long getDiskCacheEntrySizeInMBLimit()
This method returns the maximum size of an individual cache entry in megabytes (MB). Any cache entry that is larger than this, when evicted from memory, will not be offloaded to disk.

Returns:
The maximum of disk cache entry size in MB.

getFlushToDiskOnStop

public boolean getFlushToDiskOnStop()
This method returns a boolean to indicate whether in-memory cached objects are saved to disk when the server stops.

Returns:
boolean flushToDiskOnStop true or false

getDiskCachePerformanceLevel

public int getDiskCachePerformanceLevel()
This method returns the performance level to tune the performance of the disk cache.

Returns:
Peformance level 0=low 1=balance 2=custom 3=high

getCleanupFrequency

public long getCleanupFrequency()
This method returns a value for the disk cache cleanup frequency, in minutes. If this value is set to 0, the cleanup runs only at midnight. This setting applies only when the Disk Offload Performance Level is low, balanced, or custom. The high performance level does not require disk cleanup, and this value is ignored.

Returns:
Cleanup frequency in minutes

getDelayOffload

public boolean getDelayOffload()
This method returns a boolean to indicate whether the disk cache is using buffers for dependency IDs and templates.

Returns:
boolean delayOffload true or false

getDelayOffloadEntriesLimit

public long getDelayOffloadEntriesLimit()
This method returns a value for the maximum number of cache identifiers that are stored for an individual dependency ID or template in the disk cache metadata in memory. If this limit is exceeded, the information is offloaded to the disk. This setting applies only when the disk offload performance level is custom.

Returns:
Delay offload entries limit

getDelayOffloadDepIdBuckets

public long getDelayOffloadDepIdBuckets()
This method returns a value for the maximum number of dependency identifier buckets in the disk cache metadata in memory. If this limit is exceeded, the information is offloaded to the disk. This setting applies only when the disk cache performance level is custom.

Returns:
Delay offload dependency id buckets

getDelayOffloadTemplateBuckets

public long getDelayOffloadTemplateBuckets()
This method returns a value for the maximum number of template buckets in the disk cache metadata in memory. If this limit is exceeded, the information is offloaded to the disk. This setting applies only when the disk cache performance level is custom.

Returns:
Delay offload template buckets

getDiskCacheEvictionPolicy

public int getDiskCacheEvictionPolicy()
This method returns the eviction algorithm that the disk cache will use to evict entries once the high threshold is reached.

Returns:
Eviction policy 0=disable 1=random 2:size

getDiskCacheHighThreshold

public int getDiskCacheHighThreshold()
This method returns the high threshold is expressed in terms of the percentage of the disk cache size in GB or entries. The high value is used when limit disk cache size in GB and limit disk cache size in entries are specified.

Returns:
High threshold in percentage

getDiskCacheLowThreshold

public int getDiskCacheLowThreshold()
This method returns the low threshold is expressed in terms of the percentage of the disk cache size in GB or entries. The lower value is used when limit disk cache size in GB and limit disk cache size in entries are specified.

Returns:
Low threshold in percentage

getDiskCacheSizeInMBs

public float getDiskCacheSizeInMBs()
This method returns the current disk cache size in Megabytes (MB).

Returns:
current disk cache size in MB

IBM WebSphere Application ServerTM
Release 8