Package com.broadleafcommerce.search.index.core

Class DefaultLocalJvmLockService

java.lang.Object

com.broadleafcommerce.search.index.core.DefaultLocalJvmLockService

All Implemented Interfaces:

Distributable, LockService

public class DefaultLocalJvmLockService
extends Object
implements LockService

This component allows for the tracking of a lock reference for a single process ID or reference.

By definition, this implementation is non-distributed and only works in a single JVM. Callers should acquire a lock by calling the lock method, and then, in a finally block, call the unlock method:

 String lockName = CatalogIndexableType.PRODUCT.getName();
 boolean obtained = false;
 String key = null;
 if (! lockService.isLocked(lockName)) {
   try {
     key = lockService.lock(lockName);
     obtained = true;
     ... //Do work...
   
   } catch (LockException e) {
     //Log the error and return or retry since this lock is already in use.
   } finally {
     if (obtained) {
       try {
         lockService.unlock(lockName, key);
       } catch (LockException e) {
         //Log the error. //This should not happen unless the underlying key/reference relationship has been removed....
       }
     }
   }
 }
 

Author:

Kelly Tisdell (ktisdell)

Constructor Summary

Constructors

Constructor	Description
DefaultLocalJvmLockService()

Method Summary

Modifier and Type	Method	Description
boolean	isDistributed()	Indicates if this component is designed for use across JVMs.
boolean	isLocked(String lockName)	Checks to see if a lock has already been acquired for the referenced object.
String	lock(String lockName)	Attempts to create a lock based on the lock name.
void	unlock(String lockName, String lockKey)	Attempts to unlock the lock for the given lock name.

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultLocalJvmLockService

public DefaultLocalJvmLockService()

Method Detail

isDistributed

public final boolean isDistributed()

Description copied from interface: Distributable

Indicates if this component is designed for use across JVMs.

Specified by:

isDistributed in interface Distributable

Returns:

whether this component can be distributed across JVMs

isLocked

public boolean isLocked(@NonNull
                        String lockName)

Description copied from interface: LockService

Checks to see if a lock has already been acquired for the referenced object.

Specified by:

isLocked in interface LockService

Parameters:

lockName - the lock to check

Returns:

whether the lock has already been acquired

lock

public String lock(@NonNull
                   String lockName)
            throws LockException

Description copied from interface: LockService

Attempts to create a lock based on the lock name. This does not necessarily synchronize or otherwise block threads. It just creates a lock reference for the for the specified lock name. Additional attempts to create a lock with the same name will fail until a call is made to the unlock method to unlock the lock for the specific lock name.

Specified by:

lock in interface LockService

Parameters:

lockName - the lock to create

Returns:

the key for the created lock

Throws:

LockException - if a lock could not be obtained

unlock

public void unlock(@NonNull
                   String lockName,
                   @NonNull
                   String lockKey)
            throws LockException

Description copied from interface: LockService

Attempts to unlock the lock for the given lock name.

Specified by:

unlock in interface LockService

Parameters:

lockName - the lock to unlock

lockKey - the key for the lock

Throws:

LockException - if the lock could not be unlocked