EclipseLink Core 4.0.2 · org.eclipse.persistence.internal.helper.ReadLockManager

Field Summary

Modifier and Type	Field and Description
public static final int	FIRST_INDEX_OF_COLLECTION
private final Map<Long, List<ReadLockAcquisitionMetadata>>	mapThreadToReadLockAcquisitionMetadata We have seen that the read locks vector we have is very insufficient.
private final Vector<ConcurrencyManager>	readLocks This vector of read locks is essentially a basket of cache keys (classes that extend concurrency manager) that a specific thread has acquired for reading.
private final List<String>	removeReadLockProblemsDetected This is a field that will never be cleared.

Constructor Summary

Access	Constructor and Description
public	ReadLockManager()

Method Summary

Modifier and Type	Method and Description
public synchronized void	addReadLock(ConcurrencyManager concurrencyManager) add a concurrency manager as deferred locks to the DLM
public synchronized void	addRemoveReadLockProblemsDetected(String the detected problem problemDetected) Allow the concurrency manager to directly pump a message stating that there was a problem while decrementing the number of readers.
public synchronized ReadLockManager	clone() Overrides java.lang.Object.clone. Create a new instance `ReadLockManager` that is in all regards equal to the current instance.
public Map<Long, List<ReadLockAcquisitionMetadata>>	getMapThreadToReadLockAcquisitionMetadata() Getter for `mapThreadToReadLockAcquisitionMetadata`
public synchronized List<ConcurrencyManager>	getReadLocks() Return a set of the deferred locks
public List<String>	getRemoveReadLockProblemsDetected() Getter for `removeReadLockProblemsDetected`
public synchronized boolean	Returns: true if the current read lock manger contains no information about acquired locks that were never released or any errors detected while attempting to remove a cache key. If there is any error detected or any read lock acquired in the tracing we definitely do not want this object instance to be thrown out from our main tracing. It is probably revealing problems in read lock acquisition and released. isEmpty() True if the tracing the data on the object has been completely removed.
public synchronized void	removeReadLock(ConcurrencyManager the concurrency cache key that is about to be decrement in number of readers. concurrencyManager) During normal operation of the concurrency manager, each time a cache key is decrement in the number of readers, so must the corresponding read lock manager of the thread be told let go of the cache key object acquired for reading.

Inherited from java.lang.Object:: equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

FIRST_INDEX_OF_COLLECTION	back to summary
public static final int FIRST_INDEX_OF_COLLECTION

mapThreadToReadLockAcquisitionMetadata	back to summary
private final Map<Long, List<ReadLockAcquisitionMetadata>> mapThreadToReadLockAcquisitionMetadata We have seen that the read locks vector we have is very insufficient. We keep it for now due to the tracing code that is making use of it. But we also want to have a new tracing map with a lot more metadata

readLocks	back to summary
private final Vector<ConcurrencyManager> readLocks This vector of read locks is essentially a basket of cache keys (classes that extend concurrency manager) that a specific thread has acquired for reading. We need to create this additional logic in order to be able to reduce the readers count on a cache key whenever

removeReadLockProblemsDetected	back to summary
private final List<String> removeReadLockProblemsDetected This is a field that will never be cleared. It will be getting ADDs if any problem is detected when we try remove a read lock from our tracing.

Constructor Detail

ReadLockManager	back to summary
public ReadLockManager()

Method Detail

addReadLock	back to summary
public synchronized void addReadLock(ConcurrencyManager concurrencyManager) add a concurrency manager as deferred locks to the DLM

addRemoveReadLockProblemsDetected	back to summary
public synchronized void addRemoveReadLockProblemsDetected(String problemDetected) Allow the concurrency manager to directly pump a message stating that there was a problem while decrementing the number of readers. Parameters problemDetected:String the detected problem

addRemoveReadLockProblemsDetected

back to summary

public synchronized void addRemoveReadLockProblemsDetected(String problemDetected)

Allow the concurrency manager to directly pump a message stating that there was a problem while decrementing the number of readers.

Parameters

problemDetected:String: the detected problem

clone back to summary

clone	back to summary
public synchronized ReadLockManager clone() Overrides java.lang.Object.clone. Create a new instance `ReadLockManager` that is in all regards equal to the current instance. USE CASE: This method is meant to be used by algorithms that want to dump a snapshot of the current state of the system or to go about doing Returns:ReadLockManager Doc from java.lang.Object.clone. a clone of this instance. Annotations @Override

public synchronized ReadLockManager clone()

Overrides java.lang.Object.clone.

Create a new instance ReadLockManager that is in all regards equal to the current instance.

USE CASE:
This method is meant to be used by algorithms that want to dump a snapshot of the current state of the system or to go about doing

Returns:ReadLockManager

Doc from java.lang.Object.clone.

a clone of this instance.

Annotations

@Override

getMapThreadToReadLockAcquisitionMetadata	back to summary
public Map<Long, List<ReadLockAcquisitionMetadata>> getMapThreadToReadLockAcquisitionMetadata() Getter for `mapThreadToReadLockAcquisitionMetadata`

getReadLocks	back to summary
public synchronized List<ConcurrencyManager> getReadLocks() Return a set of the deferred locks

getRemoveReadLockProblemsDetected	back to summary
public List<String> getRemoveReadLockProblemsDetected() Getter for `removeReadLockProblemsDetected`

isEmpty	back to summary
public synchronized boolean isEmpty() True if the tracing the data on the object has been completely removed. If this is the case it is perfectly fine to remove the read lock manager from from the hash map of Thread To tis ReadLockManager Tracing. Returns:boolean true if the current read lock manger contains no information about acquired locks that were never released or any errors detected while attempting to remove a cache key. If there is any error detected or any read lock acquired in the tracing we definitely do not want this object instance to be thrown out from our main tracing. It is probably revealing problems in read lock acquisition and released.

isEmpty

back to summary

public synchronized boolean isEmpty()

True if the tracing the data on the object has been completely removed. If this is the case it is perfectly fine to remove the read lock manager from from the hash map of Thread To tis ReadLockManager Tracing.

Returns:boolean: true if the current read lock manger contains no information about acquired locks that were never released or any errors detected while attempting to remove a cache key. If there is any error detected or any read lock acquired in the tracing we definitely do not want this object instance to be thrown out from our main tracing. It is probably revealing problems in read lock acquisition and released.

removeReadLock	back to summary
public synchronized void removeReadLock(ConcurrencyManager concurrencyManager) During normal operation of the concurrency manager, each time a cache key is decrement in the number of readers, so must the corresponding read lock manager of the thread be told let go of the cache key object acquired for reading. Parameters concurrencyManager:ConcurrencyManager the concurrency cache key that is about to be decrement in number of readers.

removeReadLock

back to summary

public synchronized void removeReadLock(ConcurrencyManager concurrencyManager)

During normal operation of the concurrency manager, each time a cache key is decrement in the number of readers, so must the corresponding read lock manager of the thread be told let go of the cache key object acquired for reading.

Parameters

concurrencyManager:ConcurrencyManager: the concurrency cache key that is about to be decrement in number of readers.

public Class ReadLockManager

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