org.enhydra.dods.cache
Class DataStructCacheImpl

java.lang.Object
  org.enhydra.dods.cache.ConfigurationAdministration
      org.enhydra.dods.cache.DataStructCache
          org.enhydra.dods.cache.DataStructCacheImpl

public class DataStructCacheImpl
extends DataStructCache

This class contains data and mechanisms needed for caching data objects (or DataStruct objects) by their OIDs and provides cache configuration and administration.

Version:

2.0 15.06.2003.

Author:

Tanja Jovanovic, Nenad Vico, Zorica Suvajdzin

Field Summary

protected DODSCache	cache LRU cache for storing data (or DataStruct) objects.
protected CacheAdministration	cacheAdministration cacheAdministration attribute handles configuration settings about data (or DataStruct) object cache.
protected double	cachePercentage
protected boolean	completeCachingOn This attribute is true if the cache is complete, otherwise false.
protected boolean	fullCachingOn This attribute is true if the cache is full, otherwise false.
protected java.lang.String	initialQueryCache Initial query statement.
protected boolean	multi This attribute contains information if multi databases are used.
protected java.util.HashMap	nonVisibleList List of objects that are unvisible in the cache at the moment.
protected double	reserveFactor Reserve factor used in in query caching.
protected Statistics	statistics Table and cache statictics.
protected TableConfiguration	tableConf TableConfiguration attribute handles configuration settings about table of this cache.

Constructor Summary

DataStructCacheImpl()
Constructor().

DataStructCacheImpl(int maxCSize)
Constructor(int).

Method Summary

CoreDataStruct	addDataStruct(CoreDataStruct newDS) Adds DataStruct object to the cache.
void	checkFull() Returns information if data object (or DataStruct object) cache if "full".
CoreDataStruct	deleteDataStruct(CoreDataStruct data) Deletes DataStruct object from the cache.
int	getAsynchLoadPriority() Returns priority of asynchronous cache initialization.
CacheAdministration	getCacheAdministration(int cacheType) Returns CacheAdministration for data (or DataStruct) object cache.
java.util.Map	getCacheContent() Returns cache (data or DataStruct) content.
double	getCachePercentage() Read cache configuration from application's configuration file.
java.lang.String	getCacheType() Returns data object (or DataStruct object) cache type.
CoreDataStruct	getDataStructByHandle(java.lang.String handle) Returns DataStruct object whose String representation of OID is parameter handle.
int	getInitialCacheFetchSize()
int	getInitialDSCacheSize()
java.lang.String	getInitialQueryCache() Returns initialQueryCache.
int	getLevelOfCaching() Returns caching level.
int	getMaxExecuteTimeCacheInit() Returns the max time for which the query is not printed in application's log file durung the cache initialization.
int	getQueryTimeLimitCacheInit() Returns max number of milliseconds for which the query for cache initialization should be executed and the resulset read from ResultSet.
int	getQueryTimeoutCacheInit() Returns max number of seconds for which the query for cache initialization should be executed.
double	getReserveFactor() Returns reserveFactor.
int	getSimpleCacheRowCountLimit() Returns simpleCacheRowCountLimit.
Statistics	getStatistics() Returns statistics of used table and cache.
int	getSynchLoadRowCountLimit() Returns the max number of rows in the table for which the synchronous cache load is performed if defined by configuration.
TableConfiguration	getTableConfiguration() Returns TableConfiguration.
protected void	init() Creates cacheAdministration object for data (or DataStruct) object cache.
boolean	isComplete() Returns information if data object (or DataStruct object) cache if "complete".
boolean	isCompleteCachingOn() Returns information if data object (or DataStruct object) cache was in last check (call of isComplete() method) "complete".
boolean	isDisabled() Returns information whether the cache is disabled.
boolean	isFull() Returns information if data object (or DataStruct object) cache if "full".
boolean	isMulti() Returns information if multi databases are supported.
void	makeInvisible(java.lang.String cacheHandle)
void	makeVisible(java.lang.String cacheHandle)
DataStructCache	newInstance() Creates DataStructCacheImpl instance.
void	readConfiguration(Config tableConfig, Config cacheConfig, java.lang.String dbName) Reads table and cache configuration from application's configuration file.
void	refreshStatistics() Refreshes statistics.
CoreDataStruct	removeDataStruct(CoreDataStruct data) Removes DataStruct object from the cache.
CoreDataStruct	removeDataStruct(java.lang.String handle) Removes DataStruct object from the cache.
protected void	setAsynchLoadPriority(int priority) Sets priority of asynchronous cache initialization.
protected void	setCachePercentage(double percent)
void	setInitialCacheFetchSize(int i)
void	setInitialDSCacheSize(int i)
protected void	setInitialQueryCache(java.lang.String initQ) Sets initialQueryCache attribute.
protected void	setMaxExecuteTimeCacheInit(int maxExeTime) Sets the max time for which the query is not printed in application's log file durung the cache initialization.
protected void	setQueryTimeLimitCacheInit(int timeLimit) Sets max number of milliseconds for which the query for cache initialization should be executed and the resulset read from ResultSet.
protected void	setQueryTimeoutCacheInit(int timeout) Sets max number of seconds for which the query for cache initialization should be executed.
protected void	setReserveFactor(double res) Sets reserveFactor.
protected void	setSimpleCacheRowCountLimit(int rowCount) Sets simpleCacheRowCountLimit.
protected void	setSynchLoadRowCountLimit(int rowCount) Sets the max number of rows in the table for which the synchronous cache load is performed if defined by configuration.
void	show() Shows content of this class.
boolean	toReconfigure() Checks wheather cache reconfiguration needs to be done.
java.lang.String	toString() Shows content of this class.
CoreDataStruct	updateDataStruct(CoreDataStruct data) Updates cached DataStruct object, or inserts it in the cache if it didn't exist in the cache.

Methods inherited from class org.enhydra.dods.cache.DataStructCache

isLocked

Methods inherited from class java.lang.Object

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

Field Detail

cache

protected DODSCache cache

LRU cache for storing data (or DataStruct) objects. LRU cache keys are cache handles (String "."), and LRU cache values are data (or DataStruct) objects.

cacheAdministration

protected CacheAdministration cacheAdministration

cacheAdministration attribute handles configuration settings about data (or DataStruct) object cache.

tableConf

protected TableConfiguration tableConf

TableConfiguration attribute handles configuration settings about table of this cache.

initialQueryCache

protected java.lang.String initialQueryCache

Initial query statement. This attribute contains "where" clause which is used during data (or DataStruct) object cache initialization. If this attribute is set to "*", all rows from the table (in database) will be put in the cache.

multi

protected boolean multi

This attribute contains information if multi databases are used.

fullCachingOn

protected boolean fullCachingOn

This attribute is true if the cache is full, otherwise false.

completeCachingOn

protected boolean completeCachingOn

This attribute is true if the cache is complete, otherwise false.

statistics

protected Statistics statistics

Table and cache statictics.

nonVisibleList

protected java.util.HashMap nonVisibleList

List of objects that are unvisible in the cache at the moment. Keys of this map sre cache handles (String "."), and values are counters of how many transactions have made object with that cache handle invisible.

reserveFactor

protected double reserveFactor

Reserve factor used in in query caching. Since there is only data object (or DataStruct object) cache, without query caches, this parameter is not used.

cachePercentage

protected double cachePercentage

Constructor Detail

DataStructCacheImpl

public DataStructCacheImpl(int maxCSize)
                    throws CacheObjectException

Constructor(int). Creates data (or DataStruct) object cache with maximal size maxCSize.

Parameters:

maxCSize - maximal data (or DataStruct) object cache size.

Throws:

CacheObjectException

DataStructCacheImpl

public DataStructCacheImpl()
                    throws CacheObjectException

Constructor(). Creates data (or DataStruct) object cache with its default maximal size (the value of CacheConstants.DEFAULT_MAX_CACHE_SIZE is 10000).

Throws:

CacheObjectException

Method Detail

getCacheAdministration

public CacheAdministration getCacheAdministration(int cacheType)

Returns CacheAdministration for data (or DataStruct) object cache. Parameter cacheType can have one of these values: 0 - for CacheAdministration of data (or DataStruct) object cache 1 - for CacheAdministration of simple query cache 2 - for CacheAdministration of complex query cache There is only one cache (data (or DataStruct) object), so there is only one CacheAdministration. This method always returns this CacheAdministration, no matter what value does parameter cacheType have.

Specified by:

getCacheAdministration in class ConfigurationAdministration

Parameters:

cacheType - Type of caching. In this case, it is 0, but, since there is only one cache (data (or DataStruct) object), parameter is not checked, always is the same CacheAdministration object returned.

Returns:

CacheAdministration for data (or DataStruct) object cache.

getInitialQueryCache

public java.lang.String getInitialQueryCache()

Returns initialQueryCache. This attribute contains "where" clause which is used during data object (or DataStruct object) cache initialization.

Specified by:

getInitialQueryCache in class ConfigurationAdministration

Returns:

initialQueryCache.

setInitialQueryCache

protected void setInitialQueryCache(java.lang.String initQ)

Sets initialQueryCache attribute. This attribute contains "where" clause which is used during data object (or DataStruct object) cache initialization.

Specified by:

setInitialQueryCache in class ConfigurationAdministration

Parameters:

initQ - New value of initialQueryCache attribute.

makeInvisible

public void makeInvisible(java.lang.String cacheHandle)

makeVisible

public void makeVisible(java.lang.String cacheHandle)

getStatistics

public Statistics getStatistics()

Returns statistics of used table and cache.

Specified by:

getStatistics in class ConfigurationAdministration

Returns:

statistics of used table and cache.

refreshStatistics

public void refreshStatistics()

Refreshes statistics.

Specified by:

refreshStatistics in class ConfigurationAdministration

checkFull

public void checkFull()

Returns information if data object (or DataStruct object) cache if "full". "Full" cache contains all data objects (or DataStruct objects) from the table. The cache is "full", if data (or DataStruct) object cache is unbounded, if the cached table is read-only, and if initialQueryCache attribute is set to "*".

Specified by:

checkFull in class ConfigurationAdministration

isFull

public boolean isFull()

Returns information if data object (or DataStruct object) cache if "full". "Full" cache contains all data objects (or DataStruct objects) from the table. The cache is "full", if data (or DataStruct) object cache is unbounded, and if initialQueryCache attribute is set to "*".

Specified by:

isFull in class ConfigurationAdministration

Returns:

true if data object (or DataStruct object) cache if "full", otherwise false.

isComplete

public boolean isComplete()

Returns information if data object (or DataStruct object) cache if "complete". "Complete" cache can contain all data objects (or DataStruct objects) from the table. The cache is "complete", if data (or DataStruct) object cache is unbounded. If cache was complete, but not any more, the cache is created again, but as LRU cache.

Specified by:

isComplete in class ConfigurationAdministration

Returns:

true if data object (or DataStruct object) cache if "complete", otherwise false.

isCompleteCachingOn

public boolean isCompleteCachingOn()

Returns information if data object (or DataStruct object) cache was in last check (call of isComplete() method) "complete". "Complete" cache can contain all data objects (or DataStruct objects) from the table. The cache is "complete", if data (or DataStruct) object cache is unbounded.

Returns:

true if data object (or DataStruct object) cache was in last check "complete", otherwise false.

getCacheType

public java.lang.String getCacheType()

Returns data object (or DataStruct object) cache type. Possible values are: "none" - no caching available "lru" - cache with LRU (least-recently used) algorithm "full" - special case of LRU cache - the whole table is cached "complete" - special case of cache - the cache is a map in which the whole table can be cached (unbounded cache with initial condition other than "*"

Specified by:

getCacheType in class ConfigurationAdministration

Returns:

data object (or DataStruct object) cache type.

getLevelOfCaching

public int getLevelOfCaching()

Returns caching level. Possible values: org.enhydra.dods.cache.CacheConstants.DATA_CACHING (value 1) for data (or DataStruct) object caching without query caching, and org.enhydra.dods.cache.CacheConstants.QUERY_CACHING (value 2) for data (or DataStruct) object caching with query caching. This is data (or DataStruct) object cache without query caching, so this method returns CacheConstants.DATA_CACHING (value 1).

Specified by:

getLevelOfCaching in class ConfigurationAdministration

Returns:

value 1 (org.enhydra.dods.cache.CacheConstants.DATA_CACHING).

getTableConfiguration

public TableConfiguration getTableConfiguration()

Returns TableConfiguration.

Specified by:

getTableConfiguration in class ConfigurationAdministration

Returns:

TableConfiguration attribute.

getReserveFactor

public double getReserveFactor()

Returns reserveFactor. Reserve factor used in in query caching. Since there is only data object (or DataStruct object) cache, without query caches, this method returns 0.

Specified by:

getReserveFactor in class ConfigurationAdministration

Returns:

value 0.

setReserveFactor

protected void setReserveFactor(double res)

Sets reserveFactor. Reserve factor used in in query caching. Since there is only data object (or DataStruct object) cache, without query caches, this method does not do anything.

Specified by:

setReserveFactor in class ConfigurationAdministration

Parameters:

res - New reserveFactor.

setCachePercentage

protected void setCachePercentage(double percent)

Specified by:

setCachePercentage in class ConfigurationAdministration

getCachePercentage

public double getCachePercentage()

Description copied from class: ConfigurationAdministration

Read cache configuration from application's configuration file.

Specified by:

getCachePercentage in class ConfigurationAdministration

isDisabled

public boolean isDisabled()

Returns information whether the cache is disabled.

Specified by:

isDisabled in class ConfigurationAdministration

Returns:

true is the cache is disabled, otherwise false.

readConfiguration

public void readConfiguration(Config tableConfig,
                              Config cacheConfig,
                              java.lang.String dbName)
                       throws CacheObjectException

Reads table and cache configuration from application's configuration file.

Specified by:

readConfiguration in class ConfigurationAdministration

Parameters:

tableConfig - configuration for table of this cache.

cacheConfig - configuration for this cache.

Throws:

CacheObjectException

newInstance

public DataStructCache newInstance()
                            throws CacheObjectException

Creates DataStructCacheImpl instance.

Specified by:

newInstance in class DataStructCache

Returns:

created DataStructCacheImpl instance as DataStructCache.

Throws:

CacheObjectException

init

protected void init()

Creates cacheAdministration object for data (or DataStruct) object cache.

getCacheContent

public java.util.Map getCacheContent()

Returns cache (data or DataStruct) content.

Specified by:

getCacheContent in class DataStructCache

Returns:

Cache content as Map of data (or DataStruct) object.

isMulti

public boolean isMulti()

Returns information if multi databases are supported.

Specified by:

isMulti in class DataStructCache

Returns:

true if multi databases are used, otherwise false.

getAsynchLoadPriority

public int getAsynchLoadPriority()

Returns priority of asynchronous cache initialization. The priority can have value 0 or positive value. The lower the value, the higher priority. The default value is -1 (cache initialization is done synchronous).

Specified by:

getAsynchLoadPriority in class ConfigurationAdministration

Returns:

priority of asynchronous cache initialization.

setAsynchLoadPriority

protected void setAsynchLoadPriority(int priority)

Sets priority of asynchronous cache initialization. The priority can have value 0 or positive value. The lower the value, the higher priority. The value -1 means that cache initialization is done synchronous.

Specified by:

setAsynchLoadPriority in class ConfigurationAdministration

Parameters:

priority - priority of asynchronous cache initialization.

getSimpleCacheRowCountLimit

public int getSimpleCacheRowCountLimit()

Returns simpleCacheRowCountLimit. This parameter is used in in query caching. Since there is only data object (or DataStruct object) cache, without query caches, this method returns 0.

Specified by:

getSimpleCacheRowCountLimit in class ConfigurationAdministration

Returns:

value 0.

setSimpleCacheRowCountLimit

protected void setSimpleCacheRowCountLimit(int rowCount)

Sets simpleCacheRowCountLimit. This parameter is used in in query caching. Since there is only data object (or DataStruct object) cache, without query caches, this method does not do anything.

Specified by:

setSimpleCacheRowCountLimit in class ConfigurationAdministration

Parameters:

rowCount - max number of rows in the table for which is simple cache still used.

getSynchLoadRowCountLimit

public int getSynchLoadRowCountLimit()

Returns the max number of rows in the table for which the synchronous cache load is performed if defined by configuration. The default value is 0 (asynch cache load is not performed if configuration parameters for asynch cache load are not defined).

Specified by:

getSynchLoadRowCountLimit in class ConfigurationAdministration

Returns:

max number of rows in the table above which the asynch cache load is performed.

setSynchLoadRowCountLimit

protected void setSynchLoadRowCountLimit(int rowCount)

Sets the max number of rows in the table for which the synchronous cache load is performed if defined by configuration.

Specified by:

setSynchLoadRowCountLimit in class ConfigurationAdministration

Parameters:

rowCount - the max number of rows in the table for which the synchronous cache load is performed if defined by configuration.

getMaxExecuteTimeCacheInit

public int getMaxExecuteTimeCacheInit()

Returns the max time for which the query is not printed in application's log file durung the cache initialization. If the time is greater, query (SQL statement, execution time and maxExecutionTime) is printed. The default value is 0 (nothing is printed).

Specified by:

getMaxExecuteTimeCacheInit in class ConfigurationAdministration

Returns:

max time for which the query is not printed in application's log file durung the cache initialization.

setMaxExecuteTimeCacheInit

protected void setMaxExecuteTimeCacheInit(int maxExeTime)

Sets the max time for which the query is not printed in application's log file durung the cache initialization. If the time is greater, query (SQL statement, execution time and maxExecutionTime) is printed.

Specified by:

setMaxExecuteTimeCacheInit in class ConfigurationAdministration

Parameters:

maxExeTime - new value for max execution time for the cache initialization.

getQueryTimeLimitCacheInit

public int getQueryTimeLimitCacheInit()

Returns max number of milliseconds for which the query for cache initialization should be executed and the resulset read from ResultSet. If the limit is exceeded, an Exception is thrown. Value 0 means that there is no limit.

Specified by:

getQueryTimeLimitCacheInit in class ConfigurationAdministration

Returns:

max number of milliseconds for which the query for cache initialization should be executed and the resulset read from ResultSet.

setQueryTimeLimitCacheInit

protected void setQueryTimeLimitCacheInit(int timeLimit)

Sets max number of milliseconds for which the query for cache initialization should be executed and the resulset read from ResultSet. If the limit is exceeded, an Exception is thrown.

Specified by:

setQueryTimeLimitCacheInit in class ConfigurationAdministration

Parameters:

timeLimit - new value for time limit for cache initialization.

getQueryTimeoutCacheInit

public int getQueryTimeoutCacheInit()

Returns max number of seconds for which the query for cache initialization should be executed. If the limit is exceeded, an exception is thrown. Value 0 means that there is no limit.

Specified by:

getQueryTimeoutCacheInit in class ConfigurationAdministration

Returns:

the number of seconds for which the query for cache initialization should be executed.

setQueryTimeoutCacheInit

protected void setQueryTimeoutCacheInit(int timeout)

Sets max number of seconds for which the query for cache initialization should be executed. If the limit is exceeded, an exception is thrown.

Specified by:

setQueryTimeoutCacheInit in class ConfigurationAdministration

Parameters:

timeout - new value for query timeout for cache initialization.

toReconfigure

public boolean toReconfigure()

Checks wheather cache reconfiguration needs to be done.

Specified by:

toReconfigure in class DataStructCache

Returns:

true if cache reconfiguration needs to be done, otherwise false.

addDataStruct

public CoreDataStruct addDataStruct(CoreDataStruct newDS)

Adds DataStruct object to the cache.

Specified by:

addDataStruct in class DataStructCache

Parameters:

newDS - DataStruct object that will be added to the cache.

Returns:

Added DataStruct object.

removeDataStruct

public CoreDataStruct removeDataStruct(CoreDataStruct data)

Removes DataStruct object from the cache.

Specified by:

removeDataStruct in class DataStructCache

Parameters:

data - DataStruct object that will be removed from the cache.

Returns:

Removed DataStruct object, or null if there was no object removed from the cache.

removeDataStruct

public CoreDataStruct removeDataStruct(java.lang.String handle)

Removes DataStruct object from the cache.

Specified by:

removeDataStruct in class DataStructCache

Parameters:

handle - Cache handle of DataStruct object that will be removed from the cache. The form of cache handle is: ".".

Returns:

Removed DataStruct object, or null if there was no object removed from the cache.

updateDataStruct

public CoreDataStruct updateDataStruct(CoreDataStruct data)

Updates cached DataStruct object, or inserts it in the cache if it didn't exist in the cache.

Specified by:

updateDataStruct in class DataStructCache

Parameters:

data - DataStruct object that will be updated (or inserted if didn't exist in the cache).

Returns:

Updated or inserted DataStruct object.

deleteDataStruct

public CoreDataStruct deleteDataStruct(CoreDataStruct data)

Deletes DataStruct object from the cache.

Specified by:

deleteDataStruct in class DataStructCache

Parameters:

data - DataStruct object that will be deleted from the cache.

Returns:

Deleted DataStruct object, or null if there was no object deleted from the cache.

getDataStructByHandle

public CoreDataStruct getDataStructByHandle(java.lang.String handle)

Returns DataStruct object whose String representation of OID is parameter handle.

Specified by:

getDataStructByHandle in class DataStructCache

Parameters:

handle - String representation of OID of DataStruct object that is being searched in the cache.

Returns:

DataStruct object whose String representation of OID is handle.

show

public void show()

Shows content of this class. Can be used for debugging.

toString

public java.lang.String toString()

Shows content of this class. Can be used for debugging.

Overrides:

toString in class java.lang.Object

getInitialCacheFetchSize

public int getInitialCacheFetchSize()

Specified by:

getInitialCacheFetchSize in class ConfigurationAdministration

Returns:

initial cache fetch size

getInitialDSCacheSize

public int getInitialDSCacheSize()

Specified by:

getInitialDSCacheSize in class ConfigurationAdministration

Returns:

value of initial DataStruct cache size

setInitialCacheFetchSize

public void setInitialCacheFetchSize(int i)

Specified by:

setInitialCacheFetchSize in class ConfigurationAdministration

Parameters:

i -

setInitialDSCacheSize

public void setInitialDSCacheSize(int i)

Specified by:

setInitialDSCacheSize in class ConfigurationAdministration

Parameters:

i -