com.kabira.platform

Class CacheManager.Cache

java.lang.Object

com.kabira.platform.CacheManager.Cache

Enclosing class:

CacheManager

public static final class CacheManager.Cache
extends java.lang.Object

A Cache instance.

Created by the CacheManager, it is the main interface for configuring and accessing information for a named cache.

When created, the default cache size is unlimited.

Method Summary

Modifier and Type	Method and Description
void	addClass(java.lang.Class<?> klass) Associate the given class to a cache.
void	disable() Disable cache.
void	enable() Enable cache.
long	flush(long numberObjects) Flush a cache.
long	getCacheSizeBytes() Return the cache size in bytes.
int	getCacheUtilization() Return the amount of cache used as a percent.
java.lang.Iterable<java.lang.Class<?>>	getClasses() Return all known classes associated with this cache.
int	getMemoryUtilization() Return the amount of shared memory used as a percent.
java.lang.String	getName() Return the name of the cache.
long	getNumberInstances() Return the number of instances currently cached.
boolean	isDisabled() Return if the cache is currently disabled.
void	setSizeBytes(long size) Set the size of the cache in bytes.
void	setSizePercent(int percent) Set the size of the cache as a percentage.

Methods inherited from class java.lang.Object

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

Method Detail

addClass

public void addClass(java.lang.Class<?> klass)
              throws ManagedClassError,
                     CacheManager.CacheDestroyed

Associate the given class to a cache. Also associates any classes that extend the class, which are not already associated with another named cache.

If the class is already associated with a named cache, it will be removed from that cache, and added to this one. If it is already associated with this cache, no changes are made.

Parameters:

klass - Managed class to add.

Throws:

ManagedClassError - Thrown if klass is not Managed.

CacheManager.CacheDestroyed - This cache instance no longer exists.

setSizeBytes

public void setSizeBytes(long size)
                  throws java.lang.IllegalArgumentException,
                         CacheManager.CacheDestroyed

Set the size of the cache in bytes.

The system cache flusher asynchronously attempts to keep memory utilization at or below this level for objects in this cache. Note that this is not a strict size limit; object sizes will be estimated, and the flusher may run infrequently, allowing the cache to exceed the size setting.

Parameters:

size - size of cache in bytes.

Throws:

java.lang.IllegalArgumentException - The size is negative or is greater than the shared memory that is available.

CacheManager.CacheDestroyed - This cache instance no longer exists.

setSizePercent

public void setSizePercent(int percent)
                    throws CacheManager.CacheDestroyed

Set the size of the cache as a percentage.

A decimal number between 1 and 100. Indicates the maximum percentage of shared memory within the node to be used for this named cache.

If a percent of 100 is given, the cache will have no limit.

Parameters:

percent - Percent of shared memory to use for this cache.

Throws:

java.lang.IllegalArgumentException - An invalid percent was passed in.

CacheManager.CacheDestroyed - This cache instance no longer exists.

disable

public void disable()
             throws CacheManager.CacheDestroyed

Disable cache.

This disables further caching of objects. The flusher will asynchronously remove objects if the cache utilization is greater than the size, otherwise the currently cached instances will remain. If the cache is already disabled, no action is taken.

Throws:

CacheManager.CacheDestroyed - This cache instance no longer exists.

enable

public void enable()
            throws CacheManager.CacheDestroyed

Enable cache.

Enable caching of objects using the current configuration of this named cache. If the cache is already enabled, no action is taken.

Throws:

CacheManager.CacheDestroyed - This cache instance no longer exists.

flush

public long flush(long numberObjects)
           throws java.lang.IllegalArgumentException,
                  CacheManager.CacheDestroyed

Flush a cache.

This immediately flushes instances from the cache until the cache size criteria are met. Note that this may lock a significant number of object instances in the caller's transaction and should be used with care.

Index values are also removed from shared memory when the object is flushed.

Parameters:

numberObjects - Maximum number of objects to flush. A value of zero means to flush as many instances as needed.

Returns:

Number of instances flushed.

Throws:

java.lang.IllegalArgumentException - The numberObjects value is negative.

CacheManager.CacheDestroyed - This cache instance no longer exists.

getName

public java.lang.String getName()
                         throws CacheManager.CacheDestroyed

Return the name of the cache.

Returns:

String containing the name.

Throws:

CacheManager.CacheDestroyed - This cache instance no longer exists.

getClasses

public java.lang.Iterable<java.lang.Class<?>> getClasses()
                                                  throws CacheManager.CacheDestroyed

Return all known classes associated with this cache.

Returns:

Iterable containing all classes.

Throws:

CacheManager.CacheDestroyed - This cache instance no longer exists.

isDisabled

public boolean isDisabled()
                   throws CacheManager.CacheDestroyed

Return if the cache is currently disabled.

Returns:

True if the cache is disabled, otherwise false.

Throws:

CacheManager.CacheDestroyed - This cache instance no longer exists.

getNumberInstances

public long getNumberInstances()
                        throws CacheManager.CacheDestroyed

Return the number of instances currently cached.

Returns:

Number of instances in memory.

Throws:

CacheManager.CacheDestroyed - This cache instance no longer exists.

getCacheSizeBytes

public long getCacheSizeBytes()
                       throws CacheManager.CacheDestroyed

Return the cache size in bytes.

Returns:

The current cache size in bytes.

Throws:

CacheManager.CacheDestroyed - This cache instance no longer exists.

getCacheUtilization

public int getCacheUtilization()
                        throws CacheManager.CacheDestroyed

Return the amount of cache used as a percent.

If the cache setting has no limit, a value of 0 is returned. To get the percentage of total shared memory used, use the getMemoryUtilization() method.

Since the flushing of objects from the cache is asynchronous, values larger than 100 percent can be returned from this method.

Returns:

Percentage of cache used.

Throws:

CacheManager.CacheDestroyed - This cache instance no longer exists.

getMemoryUtilization

public int getMemoryUtilization()
                         throws CacheManager.CacheDestroyed

Return the amount of shared memory used as a percent.

The percentage of the node's shared memory currently in use by this cache will be calculated and returned. This value will be approximate.

Returns:

Percentage of shared memory used.

Throws:

CacheManager.CacheDestroyed - This cache instance no longer exists.