java.lang.Object
- org.copperengine.core.persistent.lock.PersistentLockManagerImpl

All Implemented Interfaces:

LockManager, PersistentLockManager
```
public class PersistentLockManagerImpl
extends java.lang.Object
implements PersistentLockManager
```
Implementation for the PersistentLockManager interface. It needs a PersistentLockManagerDialect and a TransactionController to work.

Constructor Summary

Constructors
Constructor	Description
`PersistentLockManagerImpl(PersistentProcessingEngine engine, PersistentLockManagerDialect dialect, TransactionController transactionController)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`java.lang.String`	`acquireLock(java.lang.String lockId, java.lang.String workflowInstanceId)`	Acquires a lock with the specified id.
`void`	`releaseLock(java.lang.String lockId, java.lang.String workflowInstanceId)`	Releases the specified lock.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PersistentLockManagerImpl

public PersistentLockManagerImpl(PersistentProcessingEngine engine,
                                 PersistentLockManagerDialect dialect,
                                 TransactionController transactionController)

Method Detail

acquireLock

public java.lang.String acquireLock(java.lang.String lockId,
                                    java.lang.String workflowInstanceId)

Description copied from interface: LockManager

Acquires a lock with the specified id. If the lock is free, then the lock is assigned to the caller and the methods return null.

Otherwise, if the lock is currently held by another entity, then the method returns a correlationId that the caller has to use to wait for. As soon as this lock is assigned to the caller, the lock manager creates a Response for this specified correlationId, containing the LockResult.

Example:

 private void acquireLock(final String lockId) throws Interrupt {
     for (;;) {
         logger.info("Going to acquire lock '{}'", lockId);
         final String cid = lockManager.acquireLock(lockId, this.getId());
         if (cid == null) {
             logger.info("Successfully acquired lock '{}'", lockId);
             return;
         }
         else {
             logger.info("Lock '{}' is currently not free - calling wait...", lockId);
             wait(WaitMode.ALL, 10000, cid);
             final Response<LockResult> result = getAndRemoveResponse(cid);
             logger.info("lock result={}", result);
             if (result.isTimeout()) {
                 logger.info("Failed to acquire lock: Timeout - trying again...");
             }
             else if (result.getResponse() != LockResult.OK) {
                 logger.error("Failed to acquire lock: {} - trying again...", result.getResponse());
             }
             else {
                 logger.info("Successfully acquired lock '{}'", lockId);
                 return;
             }
         }
     }
 }

Specified by:: acquireLock in interface LockManager
Parameters:: lockId - symbolic lock id; workflowInstanceId - requestor/owner of this lock
Returns:: null if the lock was free and was assigned to the caller (workflowInstanceId) otherwise a correlationId to wait for.

releaseLock
```
public void releaseLock(java.lang.String lockId,
                        java.lang.String workflowInstanceId)
```
Description copied from interface: LockManager

Releases the specified lock. If the workflow with the specified workflowId is not yet the owner of the lock (i.e. it is still waiting to retrieve the lock), the acquireLock request is removed from the queue.

Specified by:

releaseLock in interface LockManager

Parameters:

lockId - symbolic lock id

workflowInstanceId - requestor/owner of this lock

Class PersistentLockManagerImpl