atg.service.idgen
Class SQLIdGenerator

java.lang.Object
  atg.nucleus.logging.VariableArgumentApplicationLoggingImpl
      atg.nucleus.GenericService
          atg.service.idgen.AbstractSequentialIdGenerator
              atg.service.idgen.PersistentIdGenerator
                  atg.service.idgen.SQLIdGenerator

All Implemented Interfaces:

atg.naming.AbsoluteNameable, NameContextBindingListener, NameContextElement, atg.naming.NameContextParentable, NameResolver, AdminableService, atg.nucleus.Configured, ApplicationLogging, atg.nucleus.logging.ApplicationLoggingSender, atg.nucleus.logging.TraceApplicationLogging, VariableArgumentApplicationLogging, ComponentNameResolver, Service, ServiceListener, IdGenerator, java.util.EventListener

Direct Known Subclasses:

ObfuscatedSQLIdGenerator

public class SQLIdGenerator
extends PersistentIdGenerator

Persistent, sequential id generator that keeps track of ids given out using an SQL DB table. This implementation is suitable for use in a distributed system. Transactionality integrity is provided by the underlying data store, which is an SQL database.

The generated ids are generally sequential and there will generally not be gaps between ids other than when the service is stopped and restarted.

Todo

add delete functionality

See Also:

PersistentIdGenerator

Field Summary

static java.lang.String	CLASS_VERSION Class version string
protected static java.lang.String	ERR_HWM_BAD_STATE
protected static java.lang.String	ERR_HWM_FAIL
protected static java.lang.String	ERR_NULL_DS
protected static java.lang.String	ERR_QUERY_TABLE
protected static java.lang.String	ERR_RESERVE_BAD_STATE

Fields inherited from class atg.service.idgen.PersistentIdGenerator

ERR_ADD_BAD_STATE, ERR_ADD_NULL_SPACE, ERR_READING_BOOTSTRAP_SPACES, STATE_ERROR, STATE_INITIALIZING, STATE_NEW, STATE_RUNNING, WARN_PICKING_DEFAULT

Fields inherited from class atg.service.idgen.AbstractSequentialIdGenerator

ERR_BAD_SPACE, ERR_ROLLBACK, ERR_UNSUPPORTED, mSpaces, RESOURCE_BUNDLE_NAME, sResourceBundle

Fields inherited from class atg.nucleus.GenericService

SERVICE_INFO_KEY

Fields inherited from interface atg.nucleus.logging.TraceApplicationLogging

DEFAULT_LOG_TRACE_STATUS

Fields inherited from interface atg.nucleus.logging.ApplicationLogging

DEFAULT_LOG_DEBUG_STATUS, DEFAULT_LOG_ERROR_STATUS, DEFAULT_LOG_INFO_STATUS, DEFAULT_LOG_WARNING_STATUS

Constructor Summary

SQLIdGenerator()
Construct a generator

Method Summary

protected boolean	addPersistentIdSpace(IdSpace pSpace) Add an id space to the data store.
java.lang.String	getBatchSizeColumn() Get property BatchSizeColumn
javax.sql.DataSource	getDataSource() Get property DataSource
java.lang.String	getInsertSQL() Get property InsertSQL.
java.lang.String	getNameColumn() Get property NameColumn
java.lang.String	getPrefixColumn() Get property PrefixColumn
java.lang.String	getSeedColumn() Get property SeedColumn
java.lang.String	getSelectSQL() Get property SelectSQL.
java.lang.String	getSuffixColumn() Get property SuffixColumn
java.lang.String	getTableName() Get property TableName
java.lang.String	getUpdateSQL() Get property UpdateSQL.
boolean	getUseRequiredTransactionMode() Get property useRequiredTransactionMode.
protected void	initializeIdSpaces() Initialize the id spaces.
protected void	removePersistentIdSpaces() Remove all id spaces from the id generator.
protected void	reserveSeeds(IdSpace pSpace) Reserve a batch of seeds for the specified id space.
void	setBatchSizeColumn(java.lang.String pBatchSizeColumn) Set property BatchSizeColumn
void	setDataSource(javax.sql.DataSource pDataSource) Set property DataSource
void	setHighWaterMark(java.lang.String pIdSpaceName, long pHighWaterMark) Set the high water mark for the specified id space.
void	setNameColumn(java.lang.String pNameColumn) Set property NameColumn
void	setPrefixColumn(java.lang.String pPrefixColumn) Set property PrefixColumn
void	setSeedColumn(java.lang.String pSeedColumn) Set property SeedColumn
void	setSuffixColumn(java.lang.String pSuffixColumn) Set property SuffixColumn
void	setTableName(java.lang.String pTableName) Set property TableName
void	setUseRequiredTransactionMode(boolean pUseRequiredTransactionMode) Set property useRequiredTransactionMode.

Methods inherited from class atg.service.idgen.PersistentIdGenerator

addIdSpace, getInitialIdSpaces, getLoadInitialIdSpacesAtStartup, getTransactionManager, getXMLToolsFactory, initialize, removeAllIdSpaces, removeIdSpace, setInitialIdSpaces, setLoadInitialIdSpacesAtStartup, setTransactionManager, setXMLToolsFactory

Methods inherited from class atg.service.idgen.AbstractSequentialIdGenerator

doStartService, format, format, format, format, generateLongId, generateLongId, generateStringId, generateStringId, getAutoCreate, getBundle, getDefaultIdSpace, getDefaultIdSpaceName, getIdSpace, getIdSpaces, getResourceBundleName, isAutoCreate, postGenerateLongId, postGenerateStringId, setAutoCreate, setDefaultIdSpace, setDefaultIdSpaceName, toString

Methods inherited from class atg.nucleus.GenericService

addLogListener, createAdminServlet, doStopService, getAbsoluteName, getAdminServlet, getAdminServletOutputStreamEncoding, getLoggingForVlogging, getLogListenerCount, getLogListeners, getName, getNameContext, getNucleus, getRoot, getServiceConfiguration, getServiceInfo, isAdminServletUseServletOutputStream, isLoggingDebug, isLoggingError, isLoggingInfo, isLoggingTrace, isLoggingWarning, isRunning, logDebug, logDebug, logDebug, logError, logError, logError, logInfo, logInfo, logInfo, logTrace, logTrace, logTrace, logWarning, logWarning, logWarning, nameContextElementBound, nameContextElementUnbound, removeLogListener, reResolveThis, resolveName, resolveName, resolveName, resolveName, sendLogEvent, setAdminServletOutputStreamEncoding, setAdminServletUseServletOutputStream, setLoggingDebug, setLoggingError, setLoggingInfo, setLoggingTrace, setLoggingWarning, setNucleus, setServiceInfo, startService, stopService

Methods inherited from class atg.nucleus.logging.VariableArgumentApplicationLoggingImpl

vlogDebug, vlogDebug, vlogDebug, vlogDebug, vlogDebugTrace, vlogError, vlogError, vlogError, vlogError, vlogInfo, vlogInfo, vlogInfo, vlogInfo, vlogTrace, vlogTrace, vlogTrace, vlogTrace, vlogWarning, vlogWarning, vlogWarning, vlogWarning

Methods inherited from class java.lang.Object

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

Methods inherited from interface atg.service.idgen.IdGenerator

generateLongId, generateLongId, generateStringId, generateStringId, getAutoCreate, getDefaultIdSpace, getIdSpace, getIdSpaces, isAutoCreate, setAutoCreate

Field Detail

CLASS_VERSION

public static java.lang.String CLASS_VERSION

Class version string

ERR_HWM_BAD_STATE

protected static java.lang.String ERR_HWM_BAD_STATE

ERR_HWM_FAIL

protected static java.lang.String ERR_HWM_FAIL

ERR_NULL_DS

protected static java.lang.String ERR_NULL_DS

ERR_QUERY_TABLE

protected static java.lang.String ERR_QUERY_TABLE

ERR_RESERVE_BAD_STATE

protected static java.lang.String ERR_RESERVE_BAD_STATE

Constructor Detail

SQLIdGenerator

public SQLIdGenerator()

Construct a generator

Method Detail

setTableName

public void setTableName(java.lang.String pTableName)

Set property TableName

Parameters:

pTableName - new value to set

getTableName

public java.lang.String getTableName()

Get property TableName

Returns:

TableName

setNameColumn

public void setNameColumn(java.lang.String pNameColumn)

Set property NameColumn

Parameters:

pNameColumn - new value to set

getNameColumn

public java.lang.String getNameColumn()

Get property NameColumn

Returns:

NameColumn

setSeedColumn

public void setSeedColumn(java.lang.String pSeedColumn)

Set property SeedColumn

Parameters:

pSeedColumn - new value to set

getSeedColumn

public java.lang.String getSeedColumn()

Get property SeedColumn

Returns:

SeedColumn

setBatchSizeColumn

public void setBatchSizeColumn(java.lang.String pBatchSizeColumn)

Set property BatchSizeColumn

Parameters:

pBatchSizeColumn - new value to set

getBatchSizeColumn

public java.lang.String getBatchSizeColumn()

Get property BatchSizeColumn

Returns:

BatchSizeColumn

setPrefixColumn

public void setPrefixColumn(java.lang.String pPrefixColumn)

Set property PrefixColumn

Parameters:

pPrefixColumn - new value to set

getPrefixColumn

public java.lang.String getPrefixColumn()

Get property PrefixColumn

Returns:

PrefixColumn

setSuffixColumn

public void setSuffixColumn(java.lang.String pSuffixColumn)

Set property SuffixColumn

Parameters:

pSuffixColumn - new value to set

getSuffixColumn

public java.lang.String getSuffixColumn()

Get property SuffixColumn

Returns:

SuffixColumn

setDataSource

public void setDataSource(javax.sql.DataSource pDataSource)

Set property DataSource

Parameters:

pDataSource - new value to set

getDataSource

public javax.sql.DataSource getDataSource()

Get property DataSource

Returns:

DataSource

getSelectSQL

public java.lang.String getSelectSQL()

Get property SelectSQL. The SQL is lazily generated.

Returns:

SelectSQL

getInsertSQL

public java.lang.String getInsertSQL()

Get property InsertSQL. The SQL is lazily generated.

Returns:

InsertSQL

getUpdateSQL

public java.lang.String getUpdateSQL()

Get property UpdateSQL. The SQL is lazily generated.

Returns:

UpdateSQL

setUseRequiredTransactionMode

public void setUseRequiredTransactionMode(boolean pUseRequiredTransactionMode)

Set property useRequiredTransactionMode. This is a flag which, if true indicates that REQUIRED transaction mode should be used when the batch size is 1 to prevent gaps in id sequences. Normalay REQUIRES_NEW transaction mode is used. REQUIRED mode is only used if the batch size is 1 and this flag is true. This flag defaults to false. Setting this flag to true can potentially lead to deadlocks, so use it with caution.

Parameters:

pUseRequiredTransactionMode - new value to set

getUseRequiredTransactionMode

public boolean getUseRequiredTransactionMode()

Get property useRequiredTransactionMode. This is a flag which, if true indicates that REQUIRED transaction mode should be used when the batch size is 1 to prevent gaps in id sequences. Normalay REQUIRES_NEW transaction mode is used. REQUIRED mode is only used if the batch size is 1 and this flag is true. This flag defaults to false. Setting this flag to true can potentially lead to deadlocks, so use it with caution.

Returns:

useRequiredTransactionMode

addPersistentIdSpace

protected boolean addPersistentIdSpace(IdSpace pSpace)
                                throws IdGeneratorException

Add an id space to the data store. This should only be called from addIdSpace(). If the space already exsists in the DB this method reserves a batch of ids from it. IF the space does not exist it is created.

Specified by:

addPersistentIdSpace in class PersistentIdGenerator

Parameters:

pSpace - space to add, cannot be null. Nota Bene: this may be modified by this method.

Returns:

true if the space is added, or false if a space with the same name already exists in this id generator

Throws:

IdGeneratorException - if there is trouble adding id space

removePersistentIdSpaces

protected void removePersistentIdSpaces()
                                 throws IdGeneratorException

Remove all id spaces from the id generator.

Throws:

IdGeneratorException - if there is DB trouble

initializeIdSpaces

protected void initializeIdSpaces()
                           throws IdGeneratorException

Initialize the id spaces. This method attempts to load the id spaces from TableName. If that fails it tries to insert the default id space into the table. If that fails this method gives up.

This method is guaranteed to put at least one id space in the list if no exception is thrown.

Specified by:

initializeIdSpaces in class PersistentIdGenerator

Throws:

IdGeneratorException - if there is an error initializing. If initialization was unsuccessful the IdGeneratorException may have a source exception which is a chain of all of the SQLExceptions encountered during the attempt to initialize

reserveSeeds

protected void reserveSeeds(IdSpace pSpace)
                     throws IdGeneratorException

Reserve a batch of seeds for the specified id space. This method updates the id space itself with the new seed information. This method gets a connection from the DataSource for use and closes that connection when done. This method also runs in its own new transaction.

Specified by:

reserveSeeds in class PersistentIdGenerator

Parameters:

pSpace - id space to reserve seeds in, cannot be null

Throws:

IdGeneratorException - if there is DB trouble

setHighWaterMark

public void setHighWaterMark(java.lang.String pIdSpaceName,
                             long pHighWaterMark)
                      throws IdGeneratorException

Set the high water mark for the specified id space. If this method returns normally, the id generator guarantees it won't give out any ids whose integer component is less than or equal to the specified id.

Overrides:

setHighWaterMark in class AbstractSequentialIdGenerator

Parameters:

pIdSpaceName - name of id space to use

pHighWaterMark - high water mark to set

Throws:

IdGeneratorException - if the id generator cannot guarantee that the specified high water mark can be set