org.jtrim2.concurrent.query

Class SimpleDataController

java.lang.Object

org.jtrim2.concurrent.query.SimpleDataController

All Implemented Interfaces:

AsyncDataController

public final class SimpleDataController
extends Object
implements AsyncDataController

An AsyncDataController implementation which stores a volatile reference to an AsyncDataState but otherwise does nothing.

The getDataState method returns the currently set reference to the state of progress.

Note that it is safer to wrap instances of this class in a DelegatedAsyncDataController before sharing it with external code, so the external code will be unable to modify the state of progress.

Thread safety

The methods of this class are safe to be accessed by multiple threads concurrently. Instances of this class cannot be directly modified, only its state of progress if it is mutable. In case the state of progress is immutable (and it is recommended to be so), then the SimpleDataController instance is completely immutable.

Synchronization transparency

The methods of this class are synchronization transparent.

See Also:

DelegatedAsyncDataController

Constructor Summary

Constructors

Constructor and Description
SimpleDataController() Initializes the SimpleDataController with null as the state of progress.
SimpleDataController(AsyncDataState firstState) Initializes the SimpleDataController with the specified state of progress.

Method Summary

Modifier and Type	Method and Description
void	controlData(Object controlArg) This method does nothing and returns immediately to the caller.
AsyncDataState	getDataState() Returns the AsyncDataState object which was last set by the setDataState() method or the one specified at construction time if there was no setDataState() call yet.
void	setDataState(AsyncDataState newState) Sets the volatile reference to the stored AsyncDataState to the one specified.

Methods inherited from class java.lang.Object

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

Constructor Detail

SimpleDataController

public SimpleDataController()

Initializes the SimpleDataController with null as the state of progress.

Until setDataState has been called, null will be returned by the getDataState method.

SimpleDataController

public SimpleDataController(AsyncDataState firstState)

Initializes the SimpleDataController with the specified state of progress.

Parameters:

firstState - the AsyncDataState which will be returned by the getDataState() method until setDataState has been called. This argument can be null.

Method Detail

setDataState

public void setDataState(AsyncDataState newState)

Sets the volatile reference to the stored AsyncDataState to the one specified. Subsequent calls the getDataState() method will return the state specified.

Parameters:

newState - the AsyncDataState which is to be returned by the getDataState() method. This argument can be null.

controlData

public void controlData(Object controlArg)

This method does nothing and returns immediately to the caller.

Specified by:

controlData in interface AsyncDataController

Parameters:

controlArg - this argument is ignored

getDataState

public AsyncDataState getDataState()

Returns the AsyncDataState object which was last set by the setDataState() method or the one specified at construction time if there was no setDataState() call yet.

Specified by:

getDataState in interface AsyncDataController

Returns:

the AsyncDataState which was last set by the setDataState() method or the one specified at construction time if there was no setDataState() call yet. This method may return null if null was set.