Package com.complexible.common.cancellation

Class CancellationManager

java.lang.Object

com.complexible.common.cancellation.CancellationManager

All Implemented Interfaces:

Disposable

public final class CancellationManager
extends Object
implements Disposable

This is general abstraction to make 5 main functions: 1) Create cancellation point for specific database; Locks global mutex in readLock mode; Locks database-related mutex in readLock mode; 2) Execute exclusive database operation for specific database; Locks global mutex in readLock mode; Locks database-related mutex in writeLock mode; So it is impossible to create new cancellation point or to execute critical section while this lock is acquired; 3) Unregister cancellation point; Does not have locks with other operations; 4) Cancel cancellation points; Does not have locks with other operations; 5) Dispose cancellation manager (for all databases); Locks global mutex in write lock mode; It will be impossible to run all parallel methods during dispose;

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	CancellationManager.CheckedFunction<T,R>	Callable which may throw an exception.

Constructor Summary

Constructors

Constructor	Description
CancellationManager()
CancellationManager(int cancelTimeoutMs, int databaseLockTimeoutMs, int disposeTimeoutMs)

Method Summary

Modifier and Type	Method	Description
void	cancel()	Cancel all registered cancellation points;
void	cancel(String theDatabaseName)	Cancel all registered cancellation points for the specific database.
int	countCancellationPoint(String db)
void	dispose()	Dispose cancellation manager; It cancels all active cancellation points and cleanup all resources;
<T> T	executeExclusiveDatabaseOperation(String theDatabaseName, String theProcessDescription, Runnable theForceClose, CancellationManager.CheckedFunction<CancellationPoint,T> theWorker)	Executes database-critical operation; Creates a cancellation point which may be used to cancel the operation.
<T> T	executeExclusiveDatabaseOperation(String theDatabaseName, String theProcessDescription, Runnable theForceClose, Callable<T> theWorker)	Executes database-critical operation; It acquires global lock in shared mode; It acquires local per-db lock in exclusive mode;
<T> T	executeExclusiveDatabaseOperation(String theDatabaseName, String theProcessDescription, Callable<T> theWorker)
void	predisposed()
CancellationPoint	registerCancellationPoint(String theCancellationMessage, String theDatabaseName)	Register cancellation point with default thrower;
CancellationPoint	registerCancellationPoint(String theCancellationMessage, String theDatabaseName, Function<String,? extends RuntimeException> theCancellationThrower)	This method is used to register new cancellation point;
void	registerDatabase(String theDatabaseName)	Register database in the system;
void	unregisterDatabase(String theDatabaseName)	De-register database;
void	wait(String dbname, String theProcessDescription, int waitTimeMs)

Methods inherited from class java.lang.Object

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

Constructor Details

CancellationManager

public CancellationManager()

CancellationManager

public CancellationManager(int cancelTimeoutMs,
 int databaseLockTimeoutMs,
 int disposeTimeoutMs)

Method Details

registerCancellationPoint

public CancellationPoint registerCancellationPoint(String theCancellationMessage,
 String theDatabaseName)

Register cancellation point with default thrower;

Parameters:

theCancellationMessage - - the cancellation message;

theDatabaseName - - the database name;

Returns:

created cancellation point;

registerCancellationPoint

public CancellationPoint registerCancellationPoint(String theCancellationMessage,
 String theDatabaseName,
 Function<String,? extends RuntimeException> theCancellationThrower)

This method is used to register new cancellation point;

Parameters:

theCancellationMessage - - the new cancellation message;

theDatabaseName - - the database name;

theCancellationThrower - - the thrower which will be used;

Returns:

created cancellation point;

registerDatabase

public void registerDatabase(String theDatabaseName)

Register database in the system;

Parameters:

theDatabaseName - - the database name;

unregisterDatabase

public void unregisterDatabase(String theDatabaseName)

De-register database;

Parameters:

theDatabaseName - - the database name;

executeExclusiveDatabaseOperation

public <T> T executeExclusiveDatabaseOperation(String theDatabaseName,
 String theProcessDescription,
 Runnable theForceClose,
 Callable<T> theWorker)

Executes database-critical operation; It acquires global lock in shared mode; It acquires local per-db lock in exclusive mode;

Parameters:

theDatabaseName - - the database name;

theProcessDescription - - the description of process;

theForceClose - - Callback if not all CPs close after a timeout

theWorker - - the worked for execution;

Returns:

the result of the Worker's call;

executeExclusiveDatabaseOperation

public <T> T executeExclusiveDatabaseOperation(String theDatabaseName,
 String theProcessDescription,
 Callable<T> theWorker)

See Also:

• executeExclusiveDatabaseOperation(String, String, Runnable, CheckedFunction)

executeExclusiveDatabaseOperation

public <T> T executeExclusiveDatabaseOperation(String theDatabaseName,
 String theProcessDescription,
 Runnable theForceClose,
 CancellationManager.CheckedFunction<CancellationPoint,T> theWorker)

Executes database-critical operation; Creates a cancellation point which may be used to cancel the operation. It is not possible to create any new Cancellation Points before this method returns. It acquires global lock in shared mode; It acquires local per-db lock in exclusive mode;

Parameters:

theForceClose - callback if there are remaining CPs not closed after a timeout.

theWorker - the callable which will be executed with the CP

See Also:

• executeExclusiveDatabaseOperation(String, String, Callable)

cancel

public void cancel()

Cancel all registered cancellation points;

predisposed

public void predisposed()

cancel

public void cancel(String theDatabaseName)

Cancel all registered cancellation points for the specific database.

Parameters:

theDatabaseName - - the database's name;

dispose

public void dispose()

Dispose cancellation manager; It cancels all active cancellation points and cleanup all resources;

Specified by:

dispose in interface Disposable

wait

public void wait(String dbname,
 String theProcessDescription,
 int waitTimeMs)

countCancellationPoint

public int countCancellationPoint(String db)