com.goldencode.p2j.persist

Class TxWrapper.TxWrapperHelper

java.lang.Object

com.goldencode.p2j.persist.TxWrapper.TxWrapperHelper

Enclosing class:

TxWrapper

static class TxWrapper.TxWrapperHelper
extends java.lang.Object

Helper instance to access the TxWrapper.WorkArea state without context-local lookups.

Field Summary

Fields

Modifier and Type	Field and Description
private TxWrapper.WorkArea	wa The TxWrapper.WorkArea instance.

Constructor Summary

Constructors

Constructor and Description
TxWrapperHelper(TxWrapper.WorkArea wa) Initialize this helper.

Method Summary

Modifier and Type	Method and Description
void	beginTx(boolean inTx, boolean fullTx, int blockDepth) Executes logic to explicitly begin a transaction.
void	cleanDirtyBuffers(java.util.Map<java.lang.String,RecordBuffer> allBuffers) Remove all the buffers from the dirty buffers scope.
(package private) void	deregisterDynamicBuffer(RecordBuffer buffer) Deregister the given, dynamic record buffer by removing it from the buffer manager's tracking.
void	endTx(boolean inTx, boolean fullTx) Executes logic to explicitly end a transaction.
void	endTxPost() Executes logic required after a full transaction has ended.
long	getScopeTransitions() Get the number of block scope transitions made.
long	getTransactionCount() Get the current counter value of application-leve transactions which have been opened.
boolean	isImportantBlockTransition() Indicate whether the current block is "important" from the standpoint of transitioning into or out of its scope.
boolean	isTransaction() Check whether the current block is within an application-level transaction.
void	maybeActivateTxWrapper(Database database) Given a database which has one or more buffers with an open scope operating within an application level transaction, possibly activate the transaction wrapper associated with that database.
void	notifyRecordWasLoaded(RecordBuffer recordBuffer) Notify the buffer manager that a new record was loaded (or the old record was reloaded) into the specified record buffer.
(package private) void	recordFlushed(RecordBuffer buffer, int dmoId) Notification that a record has been flushed.
void	registerDirtyBuffer(RecordBuffer recordBuffer) Register this buffer as 'dirty' in the current scope.
void	registerPendingScopeable() Register the TxWrapper.WorkArea scopeable as pending, to be added to the next block.
void	trackDatabase(RecordBuffer buffer, boolean add) Track the buffer's database.

Methods inherited from class java.lang.Object

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

Field Detail

wa

private final TxWrapper.WorkArea wa

The TxWrapper.WorkArea instance.

Constructor Detail

TxWrapperHelper

public TxWrapperHelper(TxWrapper.WorkArea wa)

Initialize this helper.

Parameters:

wa - The TxWrapper.WorkArea instance.

Method Detail

registerDirtyBuffer

public void registerDirtyBuffer(RecordBuffer recordBuffer)

Register this buffer as 'dirty' in the current scope.

This registration doesn't mean that at the time of TxWrapper.commit(boolean), TxWrapper.rollback(boolean), or TxWrapper.validate(boolean, boolean) the buffer's record is still 'dirty' - this is used to limit the set of buffers receiving such notifications, to avoid iterating over all BufferManager.openBuffers.

Parameters:

recordBuffer - The record buffer.

recordFlushed

void recordFlushed(RecordBuffer buffer,
                   int dmoId)

Notification that a record has been flushed.

Parameters:

buffer - The buffer instance.

dmoId - The DMO id.

deregisterDynamicBuffer

void deregisterDynamicBuffer(RecordBuffer buffer)

Deregister the given, dynamic record buffer by removing it from the buffer manager's tracking.

Parameters:

buffer - Dynamic record buffer to be removed.

beginTx

public void beginTx(boolean inTx,
                    boolean fullTx,
                    int blockDepth)

Executes logic to explicitly begin a transaction.

Parameters:

inTx - Flag indicating if we are in a transaction.

fullTx - Flag indicating if we are in a full transaction.

blockDepth - The current block depth (all blocks tracked by the TransactionManager).

endTx

public void endTx(boolean inTx,
                  boolean fullTx)

Executes logic to explicitly end a transaction.

Parameters:

inTx - Flag indicating if we are in a transaction.

fullTx - Flag indicating if we are in a full transaction.

endTxPost

public void endTxPost()

Executes logic required after a full transaction has ended.

isTransaction

public boolean isTransaction()

Check whether the current block is within an application-level transaction.

Returns:

true if we are in a transaction, else false.

getScopeTransitions

public long getScopeTransitions()

Get the number of block scope transitions made. This is meant to be a semaphore of sorts, to allow a caller to determine whether this value has changed since some previous point when it was last retrieved. Since it is only meant to detect that the current block has changed over time, we do not protect against overflow.

Returns:

The current unique block ID.

getTransactionCount

public long getTransactionCount()

Get the current counter value of application-leve transactions which have been opened.

Returns:

Transaction count.

trackDatabase

public void trackDatabase(RecordBuffer buffer,
                          boolean add)

Track the buffer's database. This will increment the TxWrapper.WorkArea.activeDatabases counter when a new buffer is activated, and decrement it when it exists its scope.

Parameters:

buffer - The buffer to track.

add - Flag indicating if the buffer is opening or closing the scope.

Throws:

java.lang.IllegalStateException - If we are removing an active buffer and there is no entry for it in TxWrapper.WorkArea.activeDatabases.

maybeActivateTxWrapper

public void maybeActivateTxWrapper(Database database)

Given a database which has one or more buffers with an open scope operating within an application level transaction, possibly activate the transaction wrapper associated with that database. Activation entails starting a database-level transaction and activating a savepoint manager for that transaction.

If the transaction wrapper for the given database already is active, do nothing.

Parameters:

database - Database with at least one buffer with an open scope.

isImportantBlockTransition

public boolean isImportantBlockTransition()

Indicate whether the current block is "important" from the standpoint of transitioning into or out of its scope. A block is considered "important" in this sense if it is either completely outside of an application transaction, or if it is within a transaction AND has transaction block properties (i.e., is not a NO_TRANSACTION block).

This notion of importance is used to determine whether the various scoped data structures managed by this class need to add or delete a scope when transitioning into or out of the block, respectively, and whether we need to perform processing (e.g., copying/moving data between scopes) associated with such transitions.

Returns:

true if the block is considered "important" by the above criteria, else false.

registerPendingScopeable

public void registerPendingScopeable()

Register the TxWrapper.WorkArea scopeable as pending, to be added to the next block.

notifyRecordWasLoaded

public void notifyRecordWasLoaded(RecordBuffer recordBuffer)

Notify the buffer manager that a new record was loaded (or the old record was reloaded) into the specified record buffer.

Parameters:

recordBuffer - The record buffer in which a record was loaded (or the old record was reloaded).

cleanDirtyBuffers

public void cleanDirtyBuffers(java.util.Map<java.lang.String,RecordBuffer> allBuffers)

Remove all the buffers from the dirty buffers scope.

Parameters:

allBuffers - The buffers to remove.