DefaultDataSetLock (dataset 8.1.3 API)

java.lang.Object
- de.gsi.dataset.locks.DefaultDataSetLock<D>

Type Parameters:

D - generics reference, usually to <? extends DataSet>

All Implemented Interfaces:

DataSetLock<D>, Serializable
```
public class DefaultDataSetLock<D extends DataSet>
extends Object
implements DataSetLock<D>
```
A Simple ReadWriteLock for the DataSet interface and its fluent-design approach Some implementation recommendation: write lock guards behave the same as ReentrantLock with the additional functionality, that a writeLock() and subsequent writeUnLock() mute and, respectively, un-mute the given DataSet's auto-notification states, e.g. example:
```
  lock.writeLock(); // stores isAutoNotification state
     [..] some other code [..]
  lock.writeUnLock(); // restores isAutoNotification state
 
```
However, the recommended usage is using the lock guard primitives, e.g.
```
 lock.readLockGuard(() -> {
    [..] some read-lock protected code [..]
    return retVal; // N.B. optional return - here: assumes Objects or boxed primitives
 });
 
```
Alternatively the best performing option for frequent simple reads without major data processing
```
 Result ret = lock.readLockGuardOptimistic(() -> {
    [..] some read-lock protected code [..]
          return retVal; // N.B. optional return - here: assumes Objects or boxed primitives
 });
 
```
The latter assumes infrequent writes (e.g. a single writer thread) and frequent unobstructed reads (ie. many reader threads). The lock internally acquires the data w/o explicitly locking, checks afterwards if the data has potentially changed a write-lock acquiring thread, and as a automatic fall-back uses the guaranteed (but more expensive) read lock to assure that the read data structure is consistent.
Author:

rstein

See Also:

Serialized Form

Constructor Summary

Constructors
Constructor and Description

DefaultDataSetLock(D dataSet)

Constructors
Constructor and Description
`DefaultDataSetLock(D dataSet)`

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`D`	`downGradeWriteLock()` Deprecated. do not use (yet)
`long`	`getLastReadStamp()`
`boolean`	`getLastStoredAutoNotificationState()`
`long`	`getLastWriteStamp()`
`StampedLock`	`getLockObject()`
`int`	`getReaderCount()`
`int`	`getWriterCount()`
`D`	`readLock()` reentrant read-lock
`D`	`readLockGuard(Runnable reading)`
`<R> R`	`readLockGuard(Supplier<R> reading)`
`D`	`readLockGuardOptimistic(Runnable reading)`
`<R> R`	`readLockGuardOptimistic(Supplier<R> reading)`
`D`	`readUnLock()`
`protected boolean`	`threadsAreUnequal(Thread thread1, Thread thread2)`
`D`	`writeLock()`
`D`	`writeLockGuard(Runnable writing)`
`<R> R`	`writeLockGuard(Supplier<R> writing)`
`D`	`writeUnLock()`

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

- Constructor Detail
  - DefaultDataSetLock
```
public DefaultDataSetLock(D dataSet)
```
    Parameters:
    
    dataSet - dataSet this set is associate with
- Method Detail
  - downGradeWriteLock
```
@Deprecated
public D downGradeWriteLock()
```
    Deprecated. do not use (yet)
    
    experimental down-grading of the writer lock
    
    Returns:
    
    corresponding data set
  - getLastReadStamp
```
public long getLastReadStamp()
```
    Returns:
    
    last reader stamp
    
    See Also:
    
    StampedLock
  - getLastStoredAutoNotificationState
```
public boolean getLastStoredAutoNotificationState()
```
    Returns:
    
    the last stored auto-notification state
  - getLastWriteStamp
```
public long getLastWriteStamp()
```
    Returns:
    
    last writer stamp
    
    See Also:
    
    StampedLock
  - getLockObject
```
public StampedLock getLockObject()
```
    Returns:
    
    the internal StampedLock object
  - getReaderCount
```
public int getReaderCount()
```
    Returns:
    
    number of readers presently locked on this data set
  - getWriterCount
```
public int getWriterCount()
```
    Returns:
    
    number of writers presently locked on this data set (N.B. all from the same thread)
  - readLock
```
public D readLock()
```
    Description copied from interface: DataSetLock
    
    reentrant read-lock
    
    Specified by:
    
    readLock in interface DataSetLock<D extends DataSet>
    
    Returns:
    
    supporting DataSet (fluent design)
  - readLockGuard
```
public D readLockGuard(Runnable reading)
```
    Specified by:
    
    readLockGuard in interface DataSetLock<D extends DataSet>
    
    Parameters:
    
    reading - typ. lambda expression that is executed with read lock
    
    Returns:
    
    supporting DataSet (fluent design)
  - readLockGuard
```
public <R> R readLockGuard(Supplier<R> reading)
```
    Specified by:
    
    readLockGuard in interface DataSetLock<D extends DataSet>
    
    Type Parameters:
    
    R - generic return type
    
    Parameters:
    
    reading - typ. lambda expression that is executed with read lock
    
    Returns:
    
    supporting DataSet (fluent design)
  - readLockGuardOptimistic
```
public D readLockGuardOptimistic(Runnable reading)
```
    Specified by:
    
    readLockGuardOptimistic in interface DataSetLock<D extends DataSet>
    
    Parameters:
    
    reading - typ. lambda expression that is executed with read lock
    
    Returns:
    
    supporting DataSet (fluent design)
  - readLockGuardOptimistic
```
public <R> R readLockGuardOptimistic(Supplier<R> reading)
```
    Specified by:
    
    readLockGuardOptimistic in interface DataSetLock<D extends DataSet>
    
    Type Parameters:
    
    R - generic return type
    
    Parameters:
    
    reading - typ. lambda expression that is executed with read lock
    
    Returns:
    
    supporting DataSet (fluent design)
  - readUnLock
```
public D readUnLock()
```
    Specified by:
    
    readUnLock in interface DataSetLock<D extends DataSet>
    
    Returns:
    
    supporting DataSet (fluent design)
  - writeLock
```
public D writeLock()
```
    Specified by:
    
    writeLock in interface DataSetLock<D extends DataSet>
    
    Returns:
    
    supporting DataSet (fluent design)
  - writeLockGuard
```
public D writeLockGuard(Runnable writing)
```
    Specified by:
    
    writeLockGuard in interface DataSetLock<D extends DataSet>
    
    Parameters:
    
    writing - typ. lambda expression that is executed with write lock
    
    Returns:
    
    supporting DataSet (fluent design)
  - writeLockGuard
```
public <R> R writeLockGuard(Supplier<R> writing)
```
    Specified by:
    
    writeLockGuard in interface DataSetLock<D extends DataSet>
    
    Type Parameters:
    
    R - generic return type
    
    Parameters:
    
    writing - typ. lambda expression that is executed with write lock
    
    Returns:
    
    supporting DataSet (fluent design)
  - writeUnLock
```
public D writeUnLock()
```
    Specified by:
    
    writeUnLock in interface DataSetLock<D extends DataSet>
    
    Returns:
    
    supporting DataSet (fluent design)
  - threadsAreUnequal
```
protected boolean threadsAreUnequal(Thread thread1,
                                    Thread thread2)
```

Class DefaultDataSetLock<D extends DataSet>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

DefaultDataSetLock

Method Detail

downGradeWriteLock

getLastReadStamp

getLastStoredAutoNotificationState

getLastWriteStamp

getLockObject

getReaderCount

getWriterCount

readLock

readLockGuard

readLockGuard

readLockGuardOptimistic

readLockGuardOptimistic

readUnLock

writeLock

writeLockGuard

writeLockGuard

writeUnLock

threadsAreUnequal