Module org.eclipse.persistence.core

Package org.eclipse.persistence.internal.history

Class HistoricalSession

java.lang.Object

org.eclipse.persistence.internal.core.sessions.CoreAbstractSession<ClassDescriptor,Login,Platform,Project,SessionEventManager>

org.eclipse.persistence.internal.sessions.AbstractSession

org.eclipse.persistence.internal.history.HistoricalSession

All Implemented Interfaces:

Serializable, Cloneable, CoreSession<ClassDescriptor,Login,Platform,Project,SessionEventManager>, CommandProcessor, Session

public class HistoricalSession
extends AbstractSession

INTERNAL: Purpose: Allows the reading of objects as of a past time.

Description: All queries executed through this special lightweight session will return results as of a past time. Objects read will be cached in a special isolated cache.

Responsibilities:

• Execute all read queries as of a past time.
• Insure that all objects read are cached in an Identity map completely isolated from that of its parent.
• Once a query has been uniquely prepared to read past objects, execute the call on the parent session.

Since:

OracleAS TopLink 10g (10.1.3)

See Also:

• Session.acquireHistoricalSession(org.eclipse.persistence.history.AsOfClause)
• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected final AsOfClause	asOfClause
protected final AbstractSession	parent

Fields inherited from class org.eclipse.persistence.internal.sessions.AbstractSession

accessors, activeCommandThreads, attributeGroups, broker, commandManager, commitManager, defaultReferenceMode, deferredEvents, descriptors, eventManager, exceptionHandler, externalTransactionController, identityMapAccessor, injectionManager, integrityChecker, isConcurrent, isExecutingEvents, isFinalizersEnabled, isInBroker, isInProfile, isLoggingOff, isSynchronized, jpaQueriesProcessed, lastDescriptorAccessed, logSessionString, metadatalistener, multitenantContextProperties, name, numberOfActiveUnitsOfWork, objectsLockedForClone, partitioningPolicy, pessimisticLockTimeoutDefault, pessimisticLockTimeoutUnitDefault, platform, profiler, project, properties, queries, queryBuilder, queryTimeoutDefault, queryTimeoutUnitDefault, serializer, sessionLog, shouldCheckWriteLock, shouldOptimizeResultSetAccess, shouldPropagateChanges, staticMetamodelClasses, tablePerTenantDescriptors, tablePerTenantQueries, tolerateInvalidJPQL, transactionMutex, wasJTSTransactionInternallyStarted

Fields inherited from interface org.eclipse.persistence.sessions.coordination.CommandProcessor

LOG_DEBUG, LOG_ERROR, LOG_INFO, LOG_WARNING

Constructor Summary

Constructors

Constructor	Description
HistoricalSession(AbstractSession parent, AsOfClause clause)	INTERNAL: Create and return a new Historical Session.

Method Summary

Modifier and Type	Method	Description
Session	acquireHistoricalSession(AsOfClause clause)	INTERNAL: Acquires a special historical session for reading objects as of a past time.
UnitOfWorkImpl	acquireUnitOfWork()	INTERNAL: A UnitOfWork can not be acquired from a Historical Session.
void	beginTransaction()	INTERNAL: No transactions should be used inside a HistoricalSession.
void	commitTransaction()	INTERNAL: No transactions should be used inside a HistoricalSession.
AsOfClause	getAsOfClause()	ADVANCED: Answers a read-only data object, which knows whether it is a wall-clock time or a system change number.
Object	getAsOfValue()	PUBLIC: Answers the value this Session is As Of.
AbstractSession	getExecutionSession(DatabaseQuery query)	INTERNAL: Gets the session which this query will be executed on.
AbstractSession	getParent()	INTERNAL: Returns the parent Session.
ServerPlatform	getServerPlatform()	INTERNAL: Marked internal as this is not customer API but helper methods for accessing the server platform from within TopLink's other sessions types (ie not DatabaseSession)
boolean	hasAsOfClause()	ADVANCED: Answers if all objects are to be read as of a past time.
Object	internalExecuteQuery(DatabaseQuery query, AbstractRecord databaseRow)	INTERNAL: Return the results from executing the database query.
boolean	isHistoricalSession()	INTERNAL: Return if this session is a historical session.
boolean	isInTransaction()	INTERNAL: Historical session are never in a transaction.
DatabaseQuery	prepareDatabaseQuery(DatabaseQuery query)	INTERNAL: A call back to do session specific preparation of a query.
void	rollbackTransaction()	INTERNAL: No transactions should be used inside a HistoricalSession.
String	toString()	Print the connection status with the session.

Methods inherited from class org.eclipse.persistence.internal.sessions.AbstractSession

acquireNonSynchronizedUnitOfWork, acquireNonSynchronizedUnitOfWork, acquireRepeatableWriteUnitOfWork, acquireUnitOfWork, addAlias, addJPAQuery, addJPATablePerTenantQuery, addMultitenantContextProperty, addQuery, addQuery, addQuery, addStaticMetamodelClass, addTablePerTenantDescriptor, addTablePerTenantQuery, basicBeginTransaction, basicBeginTransaction, basicCommitTransaction, basicExecuteCall, basicRollbackTransaction, beginExternalTransaction, buildDefaultQueryBuilder, checkAndRefreshInvalidObject, checkHierarchyForDescriptor, cleanUpInjectionManager, clearDescriptors, clearIntegrityChecker, clearLastDescriptorAccessed, clearProfile, clone, commitExternalTransaction, compareObjects, compareObjectsDontMatch, config, containsQuery, copy, copy, copyDescriptorNamedQueries, copyDescriptorsFromProject, copyInternal, copyReadOnlyClasses, createCloneQueryValueHolder, createCloneTransformationValueHolder, createInjectionManager, createProtectedInstanceFromCachedData, deferEvent, deleteAllObjects, deleteObject, doesObjectExist, dontLogMessages, endOperationProfile, endOperationProfile, executeCall, executeDeferredEvents, executeNonSelectingCall, executeNonSelectingSQL, executeQuery, executeQuery, executeQuery, executeQuery, executeQuery, executeQuery, executeQuery, executeQuery, executeQuery, executeQuery, executeQuery, executeQuery, executeQuery, executeQuery, executeQuery, executeQuery, executeSelectingCall, executeSQL, fine, finer, finest, getAccessor, getAccessors, getAccessors, getActiveCommandThreads, getActiveSession, getActiveUnitOfWork, getAliasDescriptors, getAllQueries, getAttributeGroups, getBroker, getCacheKeyFromTargetSessionForMerge, getClassDescriptor, getClassDescriptor, getClassDescriptorForAlias, getCommandManager, getCommitManager, getDatasourceLogin, getDatasourcePlatform, getDefaultReadOnlyClasses, getDefaultReferenceMode, getDescriptor, getDescriptor, getDescriptorForAlias, getDescriptors, getEventManager, getExceptionHandler, getExceptionHandlerClass, getExternalTransactionController, getId, getIdentityMapAccessor, getIdentityMapAccessorInstance, getInjectionManager, getIntegrityChecker, getJPAQueries, getJPATablePerTenantQueries, getLoader, getLog, getLogin, getLogLevel, getLogLevel, getLogSessionString, getMappedSuperclass, getMultitenantContextProperties, getName, getNextQueryId, getNextSequenceNumberValue, getNumberOfActiveUnitsOfWork, getParentIdentityMapSession, getParentIdentityMapSession, getParentIdentityMapSession, getPartitioningPolicy, getPessimisticLockTimeoutDefault, getPessimisticLockTimeoutUnitDefault, getPlatform, getPlatform, getProfiler, getProject, getProperties, getProperty, getQueries, getQuery, getQuery, getQuery, getQuery, getQueryBuilder, getQueryTimeoutDefault, getQueryTimeoutUnitDefault, getRefreshMetadataListener, getRootSession, getSequencing, getSerializer, getSessionForClass, getSessionForName, getSessionLog, getSessionTypeString, getStaticMetamodelClass, getTablePerTenantDescriptors, getTablePerTenantQueries, getTransactionMutex, handleException, handleSevere, hasBroker, hasCommitManager, hasDescriptor, hasEventManager, hasExceptionHandler, hasExternalTransactionController, hasProperties, hasTablePerTenantDescriptors, hasTablePerTenantQueries, incrementProfile, incrementProfile, info, initializeIdentityMapAccessor, insertObject, isBroker, isClassReadOnly, isClassReadOnly, isClientSession, isConcurrent, isConnected, isConsideredInvalid, isDatabaseSession, isDistributedSession, isExclusiveConnectionRequired, isExclusiveIsolatedClientSession, isFinalizersEnabled, isInBroker, isInProfile, isIsolatedClientSession, isJPAQueriesProcessed, isLoggingOff, isProtectedSession, isRemoteSession, isRemoteUnitOfWork, isServerSession, isSessionBroker, isSynchronized, isUnitOfWork, keyFromObject, load, load, log, log, log, log, log, log, log, log, logMessage, logMessage, logThrowable, postAcquireConnection, preReleaseConnection, priviledgedExecuteNonSelectingCall, priviledgedExecuteSelectingCall, processCommand, processJPAQueries, processJPAQuery, readAllObjects, readAllObjects, readAllObjects, readAllObjects, readObject, readObject, readObject, readObject, readObject, refreshAndLockObject, refreshAndLockObject, refreshObject, registerFinalizer, release, releaseConnectionAfterCall, releaseJTSConnection, releaseReadConnection, releaseUnitOfWork, removeProperty, removeQuery, removeQuery, retrieveCacheKey, retryQuery, retryTransaction, rollbackExternalTransaction, setAccessor, setBroker, setCommandManager, setCommitManager, setDatasourceLogin, setDefaultReferenceMode, setEventManager, setExceptionHandler, setExternalTransactionController, setInjectionManager, setIntegrityChecker, setIsConcurrent, setIsFinalizersEnabled, setIsInBroker, setIsInProfile, setJPAQueriesProcessed, setLog, setLoggingOff, setLogin, setLogin, setLogLevel, setName, setNumberOfActiveUnitsOfWork, setPartitioningPolicy, setPessimisticLockTimeoutDefault, setPessimisticLockTimeoutUnitDefault, setProfiler, setProject, setProperties, setProperty, setQueries, setQueryBuilder, setQueryTimeoutDefault, setQueryTimeoutUnitDefault, setRefreshMetadataListener, setSerializer, setSessionLog, setShouldOptimizeResultSetAccess, setShouldPropagateChanges, setSynchronized, setTolerateInvalidJPQL, setTransactionMutex, setWasJTSTransactionInternallyStarted, severe, shouldDisplayData, shouldLog, shouldLogMessages, shouldLogMessages, shouldOptimizeResultSetAccess, shouldPropagateChanges, shouldTolerateInvalidJPQL, startOperationProfile, startOperationProfile, unwrapObject, updateObject, updateProfile, updateTablePerTenantDescriptors, validateCache, validateQuery, verifyDelete, warning, wasJTSTransactionInternallyStarted, wrapObject, writeAllObjectsWithChangeSet, writeObject, writesCompleted

Methods inherited from class java.lang.Object

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

Field Details

parent

protected final AbstractSession parent

asOfClause

protected final AsOfClause asOfClause

Constructor Details

HistoricalSession

public HistoricalSession(AbstractSession parent,
 AsOfClause clause)

INTERNAL: Create and return a new Historical Session.

Method Details

acquireHistoricalSession

public Session acquireHistoricalSession(AsOfClause clause)
                                 throws ValidationException

INTERNAL: Acquires a special historical session for reading objects as of a past time.

Specified by:

acquireHistoricalSession in interface Session

Overrides:

acquireHistoricalSession in class AbstractSession

Parameters:

clause - Represents a valid snap shot time.

Throws:

ValidationException - if this not a ClientSession, plain Session, or SessionBroker.

See Also:

• AsOfClause
• Expression.asOf(org.eclipse.persistence.history.AsOfClause)
• ObjectLevelReadQuery.setAsOfClause(org.eclipse.persistence.history.AsOfClause)
• HistoryPolicy

acquireUnitOfWork

public UnitOfWorkImpl acquireUnitOfWork()

INTERNAL: A UnitOfWork can not be acquired from a Historical Session.

Specified by:

acquireUnitOfWork in interface Session

Overrides:

acquireUnitOfWork in class AbstractSession

See Also:

• UnitOfWorkImpl

beginTransaction

public void beginTransaction()
                      throws DatabaseException,
ConcurrencyException

INTERNAL: No transactions should be used inside a HistoricalSession.

Overrides:

beginTransaction in class AbstractSession

Throws:

DatabaseException - if the database connection is lost or the begin is rejected.

ConcurrencyException - if this session's transaction is acquired by another thread and a timeout occurs.

See Also:

• AbstractSession.isInTransaction()

commitTransaction

public void commitTransaction()
                       throws DatabaseException,
ConcurrencyException

INTERNAL: No transactions should be used inside a HistoricalSession.

Overrides:

commitTransaction in class AbstractSession

Throws:

DatabaseException - most databases validate changes as they are done, normally errors do not occur on commit unless the disk fails or the connection is lost.

ConcurrencyException - if this session is not within a transaction.

getExecutionSession

public AbstractSession getExecutionSession(DatabaseQuery query)

INTERNAL: Gets the session which this query will be executed on. Generally will be called immediately before the call is translated, which is immediately before session.executeCall.

Since the execution session also knows the correct datasource platform to execute on, it is often used in the mappings where the platform is needed for type conversion, or where calls are translated.

Is also the session with the accessor. Will return a ClientSession if it is in transaction and has a write connection.

Overrides:

getExecutionSession in class AbstractSession

Parameters:

query - may store session name or reference class for brokers case

Returns:

a session with a live accessor

getAsOfClause

public AsOfClause getAsOfClause()

ADVANCED: Answers a read-only data object, which knows whether it is a wall-clock time or a system change number.

Specified by:

getAsOfClause in interface Session

Overrides:

getAsOfClause in class AbstractSession

Returns:

An immutable object representation of the past time. null if no clause set, or this a regular session.

See Also:

• AbstractSession.acquireHistoricalSession(org.eclipse.persistence.history.AsOfClause)

getAsOfValue

public Object getAsOfValue()

PUBLIC: Answers the value this Session is As Of. Equivalent to getAsOfClause().getValue().

getParent

public AbstractSession getParent()

INTERNAL: Returns the parent Session.

Overrides:

getParent in class AbstractSession

getServerPlatform

public ServerPlatform getServerPlatform()

INTERNAL: Marked internal as this is not customer API but helper methods for accessing the server platform from within TopLink's other sessions types (ie not DatabaseSession)

Specified by:

getServerPlatform in interface Session

Overrides:

getServerPlatform in class AbstractSession

hasAsOfClause

public boolean hasAsOfClause()

ADVANCED: Answers if all objects are to be read as of a past time. Only true if this is a special historical session.

See Also:

• getAsOfClause()

internalExecuteQuery

public Object internalExecuteQuery(DatabaseQuery query,
 AbstractRecord databaseRow)
                            throws DatabaseException

INTERNAL: Return the results from executing the database query. the arguments should be a database row with raw data values. No modify queries are allowed through a HistoricalSession.

Overrides:

internalExecuteQuery in class AbstractSession

Throws:

DatabaseException

isInTransaction

public boolean isInTransaction()

INTERNAL: Historical session are never in a transaction.

Overrides:

isInTransaction in class AbstractSession

isHistoricalSession

public boolean isHistoricalSession()

INTERNAL: Return if this session is a historical session.

Overrides:

isHistoricalSession in class AbstractSession

prepareDatabaseQuery

public DatabaseQuery prepareDatabaseQuery(DatabaseQuery query)

INTERNAL: A call back to do session specific preparation of a query.

The call back occurs immediately before we clone the query for execution, meaning that if this method needs to clone the query then the caller will determine that it doesn't need to clone the query twice.

Overrides:

prepareDatabaseQuery in class AbstractSession

rollbackTransaction

public void rollbackTransaction()
                         throws DatabaseException,
ConcurrencyException

INTERNAL: No transactions should be used inside a HistoricalSession.

Overrides:

rollbackTransaction in class AbstractSession

Throws:

DatabaseException - if the database connection is lost or the rollback fails.

ConcurrencyException - if this session is not within a transaction.

toString

public String toString()

Description copied from class: AbstractSession

Print the connection status with the session.

Overrides:

toString in class AbstractSession