cz.ues.platform.concurrent

Class UESLock

java.lang.Object

cz.ues.platform.concurrent.UESLock

public class UESLock
extends java.lang.Object

UESLock is a helper class for secure lock handling. Basic usage pattern:

   UESLock lock = UESLock.create(resourceUri, createDto);
   try {
     // ...
     // a business logic here
     // ... 
   } finally {
     lock.unlock();
   }
 

Since:

UES7-10

Field Summary

Fields

Modifier and Type	Field and Description
private static long	DEFAULT_WAIT_TIMEOUT Default timeout for which can process wait for lock creation or resource unlock.
private UESLockManager	lockMng Instance of lock manager.
private UESURI	lockUri Lock URI.
private static long	MAXIMUM_WAIT_TIMEOUT Maximum timeout for which can process wait for lock creation or resource unlock.

Constructor Summary

Constructors

Modifier	Constructor and Description
private	UESLock(UESLockAttributes lock) Creates new instance of UESLock.

Method Summary

Methods

Modifier and Type	Method and Description
static UESLock	create(UESURI resourceUri, UESLockCreate lock) Creates new lock.
private static java.lang.String	getOwnerId() Returns owner ID (in case owner ID does not exists yet new one is generated and stored as retained parameter on PCB).
UESURI	getUri() Returns UESURI of this lock.
boolean	isValid() Checks if lock is valid (e.g. is not expired or was not removed by other process).
void	reallocate(java.lang.Long lockTimeout) Reallocates lock and thus allows prolonging (or shortening) its expiration time.
void	unlock() Unlocks lock.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_WAIT_TIMEOUT

private static final DEFAULT_WAIT_TIMEOUT

Default timeout for which can process wait for lock creation or resource unlock.

See Also:

Constant Field Values

MAXIMUM_WAIT_TIMEOUT

private static final MAXIMUM_WAIT_TIMEOUT

Maximum timeout for which can process wait for lock creation or resource unlock.

See Also:

Constant Field Values

lockMng

private lockMng

Instance of lock manager.

lockUri

private lockUri

Lock URI.

Constructor Detail

UESLock

private UESLock(UESLockAttributes lock)

Creates new instance of UESLock.

Parameters:

lock - Attributes of created lock

Since:

UES7-10

Method Detail

create

public static UESLock create(UESURI resourceUri,
UESLockCreate lock)

Creates new lock.

Parameters:

resourceUri - UESURI of resource to be locked

lock - Additional lock attributes

Returns:

Instance of lock or null if lock was not create (e.g. resource is already locked)

Since:

UES7-10

isValid

public boolean isValid()

Checks if lock is valid (e.g. is not expired or was not removed by other process).

Returns:

True if lock is valid, else false

Since:

UES7-10

reallocate

public void reallocate(java.lang.Long lockTimeout)

Reallocates lock and thus allows prolonging (or shortening) its expiration time. In case lock was already removed (e.g. is already expired, or was removed by other process), exception is thrown.

Parameters:

lockTimeout - New value of lock timeout in seconds (may be null or -1 to maintain lock timeout initially set on lock create)

Since:

UES7-10

unlock

public void unlock()

Unlocks lock. In case lock is not valid in time of its unlock exception is thrown.

Since:

UES7-10

getUri

public UESURI getUri()

Returns UESURI of this lock.

Returns:

UESURI of this lock

Since:

UES8-08

getOwnerId

private static java.lang.String getOwnerId()

Returns owner ID (in case owner ID does not exists yet new one is generated and stored as retained parameter on PCB).

Returns:

Owner ID

Since:

UES7-10