atg.service.idgen
Class ObfuscatedSQLIdGenerator

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

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

public class ObfuscatedSQLIdGenerator
extends SQLIdGenerator

Persistent, obfuscated id generator that keeps track of ids given out using an SQL DB table.

This implementation obfuscates the generated ids in two ways. First, for a given batch of reservered ids this implementation only gives out a few ids. Second, ids can be optionally hex encoded when being used as String ids. Both the String and long ids generated use a pseudorandom number generator to get a long id from the current batch of ids. In addition to not giving out the same id twice, this implementation will not given out adjacent long ids (or String ids that come from adjacent long ids).

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 IdSpace properties batchSize and idsPerBatch are used in conjunction. batchSize works as in the SQLIdGenerator. idsPerBatch is the maximum never of ids that will be given out in any given batch.

It is strongly recommended that idsPerBatch be less than 1% of the batchSize. This is both for security and performance. For security a sparse (i.e., less dense) id space makes it harder to guess ids. Since this implementation does not give out adjacent ids, it could be forced to do more work to find suitable ids if the id space is too dense. This implementation will not allow an id space to be added that is denser than 10%. That is, idsPerBatch / batchSize must be less than .1. Always set these two properties together to maintain the 1% density goal.

The recommended values for batchSize and idsPerBatch are 100,000 and 997, respectively. These numbers are not magic. 100,000 is the default batch size. 997 is a prime number that is slightly less than 1% of the batch size.

See Also:

PersistentIdGenerator, SQLIdGenerator

Field Summary

static java.lang.String	CLASS_VERSION Class version string
protected static java.lang.String	ERR_TOO_DENSE
static float	MAX_DENSITY maximum density for obfuscated id generators

Fields inherited from class atg.service.idgen.SQLIdGenerator

ERR_HWM_BAD_STATE, ERR_HWM_FAIL, ERR_NULL_DS, ERR_QUERY_TABLE, 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

ObfuscatedSQLIdGenerator()
Construct a generator

Method Summary

boolean	addIdSpace(IdSpace pSpace) Add an id space to the id generator.
protected boolean	addPersistentIdSpace(IdSpace pSpace) Add an id space to the data store.
protected void	createNewDefaultIdSpace() Make sure the default id space exists, creating it if necessary.
boolean	getHexEncode() Get property hexEncode
java.lang.String	getIdsPerBatchColumn() Get property idsPerBatchColumn
java.lang.String	getInsertSQL() Get property InsertSQL.
java.lang.String	getSelectSQL() Get property SelectSQL.
java.lang.String	getUpdateSQL() Get property UpdateSQL.
boolean	isHexEncode() Test property hexEncode
protected void	reserveSeeds(IdSpace pSpace) Reserve a batch of seeds for the specified id space.
void	setHexEncode(boolean pHexEncode) Set property hexEncode
void	setIdsPerBatchColumn(java.lang.String pIdsPerBatchColumn) Set property idsPerBatchColumn

Methods inherited from class atg.service.idgen.SQLIdGenerator

getBatchSizeColumn, getDataSource, getNameColumn, getPrefixColumn, getSeedColumn, getSuffixColumn, getTableName, getUseRequiredTransactionMode, initializeIdSpaces, removePersistentIdSpaces, setBatchSizeColumn, setDataSource, setHighWaterMark, setNameColumn, setPrefixColumn, setSeedColumn, setSuffixColumn, setTableName, setUseRequiredTransactionMode

Methods inherited from class atg.service.idgen.PersistentIdGenerator

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

MAX_DENSITY

public static float MAX_DENSITY

maximum density for obfuscated id generators

ERR_TOO_DENSE

protected static java.lang.String ERR_TOO_DENSE

Constructor Detail

ObfuscatedSQLIdGenerator

public ObfuscatedSQLIdGenerator()

Construct a generator

Method Detail

setIdsPerBatchColumn

public void setIdsPerBatchColumn(java.lang.String pIdsPerBatchColumn)

Set property idsPerBatchColumn

Parameters:

pIdsPerBatchColumn - new value to set

getIdsPerBatchColumn

public java.lang.String getIdsPerBatchColumn()

Get property idsPerBatchColumn

Returns:

idsPerBatchColumn

setHexEncode

public void setHexEncode(boolean pHexEncode)

Set property hexEncode

Parameters:

pHexEncode - new value to set

getHexEncode

public boolean getHexEncode()

Get property hexEncode

Returns:

hexEncode

isHexEncode

public boolean isHexEncode()

Test property hexEncode

Returns:

hexEncode

getSelectSQL

public java.lang.String getSelectSQL()

Get property SelectSQL. The SQL is lazily generated.

Overrides:

getSelectSQL in class SQLIdGenerator

Returns:

SelectSQL

getInsertSQL

public java.lang.String getInsertSQL()

Get property InsertSQL. The SQL is lazily generated.

Overrides:

getInsertSQL in class SQLIdGenerator

Returns:

InsertSQL

getUpdateSQL

public java.lang.String getUpdateSQL()

Get property UpdateSQL. The SQL is lazily generated.

Overrides:

getUpdateSQL in class SQLIdGenerator

Returns:

UpdateSQL

addIdSpace

public boolean addIdSpace(IdSpace pSpace)
                   throws IdGeneratorException

Add an id space to the id generator. The id space must not be null. This method ensures that there is an at least somewhat reasonable value for the idsPerBatch property of the id space. Somewhat reasonable means a prime number not large than roughly 1% of the batch size:

batchSize	idsPerBatch
>=100,000	997
>=10,000	89
>=else	7

Specified by:

addIdSpace in interface IdGenerator

Overrides:

addIdSpace in class PersistentIdGenerator

Parameters:

pSpace - space to add, cannot be null

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 the space

addPersistentIdSpace

protected boolean addPersistentIdSpace(IdSpace pSpace)
                                throws IdGeneratorException

Add an id space to the data store. This should only be called from addIdSpace().

Overrides:

addPersistentIdSpace in class SQLIdGenerator

Parameters:

pSpace - space to add, cannot be null

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

createNewDefaultIdSpace

protected void createNewDefaultIdSpace()

Make sure the default id space exists, creating it if necessary.

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.

Overrides:

reserveSeeds in class SQLIdGenerator

Parameters:

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

Throws:

IdGeneratorException - if there is DB trouble