Package net.algart.contexts

Class DefaultContext

java.lang.Object

net.algart.contexts.AbstractContext

net.algart.contexts.DefaultContext

All Implemented Interfaces:

ArrayMemoryContext, ArrayThreadPoolContext, Context, InterruptionContext, ProgressUpdater, StatusUpdater

public class DefaultContext
extends AbstractContext
implements Context, InterruptionContext, ArrayMemoryContext, ArrayThreadPoolContext, ProgressUpdater, StatusUpdater

An adapter class containing the simplest ("empty") implementations of the following standard contexts: InterruptionContext, ArrayMemoryContext, ArrayThreadPoolContext, ProgressUpdater, StatusUpdater. See comments to the methods of this class to clarify behavior of this implementation.

This class is an inheritor of AbstractContext, and all its constructors calls the superconstructor with the argument useServiceLoader=true. So, this class can serve requests not only for the standard context listed above, but also for any other contexts, that are specified in service providers for Context interface.

This class is a good possible superclass for implementation custom behavior of the contexts or for overriding the behavior of an existing context, specified as a service provider.

Author:

Daniel Alievsky

Nested Class Summary

Nested classes/interfaces inherited from interface net.algart.contexts.InterruptionContext

InterruptionContext.Event, InterruptionContext.Listener

Field Summary

Fields inherited from class net.algart.contexts.AbstractContext

useServiceLoader

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	DefaultContext()	This constructor prevents direct instantiation of this class.
	DefaultContext(MemoryModel memoryModel)	Creates an instance of this context with the specified memory model, which will be returned by getMemoryModel() method.

Method Summary

Modifier and Type	Method	Description
void	addInterruptionListener(InterruptionContext.Listener listener)	This implementation does nothing.
void	checkInterruption()	This implementation does nothing.
static DefaultContext	getInstance()	Returns an instance of this class, created by "new DefaultContext(){}" call.
MemoryModel	getMemoryModel()	This implementation returns the memory model, specified by the argument of the corresponding constructor, or Arrays.SystemSettings.globalMemoryModel() if the constructor without arguments was used.
MemoryModel	getMemoryModel(Class<?> elementType)	This implementation returns mm.isElementTypeSupported(elementType) ? mm : SimpleMemoryModel.getInstance(), where mm is the result of getMemoryModel() method.
MemoryModel	getMemoryModel(String settings)	This implementation calls getMemoryModel() and returns its result.
ThreadPoolFactory	getThreadPoolFactory()	This implementation returns an instance of DefaultThreadPoolFactory.
void	removeInterruptionListener(InterruptionContext.Listener listener)	This implementation does nothing.
void	updateProgress(double readyPart, boolean force)	This implementation calls updateStatus(String, boolean) with the first argument alike Math.round(readyPart*100)+"%" and the second argument force.
void	updateStatus(String message)	This implementation calls updateStatus(message, true).
void	updateStatus(String message, boolean force)	This implementation does nothing.

Methods inherited from class net.algart.contexts.AbstractContext

as, is

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.algart.contexts.Context

as, is

Constructor Details

DefaultContext

protected DefaultContext()

This constructor prevents direct instantiation of this class. Please use getInstance() method instead.

DefaultContext

public DefaultContext(MemoryModel memoryModel)

Creates an instance of this context with the specified memory model, which will be returned by getMemoryModel() method.

Parameters:

memoryModel - desired memory model.

Method Details

getInstance

public static DefaultContext getInstance()

Returns an instance of this class, created by "new DefaultContext(){}" call. This instance can be used as a simplest default implementation of most standard contexts, offered by this package: InterruptionContext, ArrayMemoryContext, ArrayThreadPoolContext, StatusUpdater, ProgressUpdater. This implementation does not allow interrupt modules, provides the default global memory model, the default thread pool factory and does nothing while attempts to show the status line or execution progress.

The result of this method is probably a singleton: all calls of this method may return the same instance.

Returns:

the default instance of this class.

checkInterruption

public void checkInterruption()

This implementation does nothing. So, this context does not allow to interrupt long-working algorithms.

The simplest possible implementation of this method in your subclass, allowing to interrupt algorithsm, may be the following:

 if (Thread.interrupted())
     throw new InterruptionException();
 

Specified by:

checkInterruption in interface InterruptionContext

addInterruptionListener

public void addInterruptionListener(InterruptionContext.Listener listener)

This implementation does nothing.

Specified by:

addInterruptionListener in interface InterruptionContext

Parameters:

listener - is ignored.

removeInterruptionListener

public void removeInterruptionListener(InterruptionContext.Listener listener)

This implementation does nothing.

Specified by:

removeInterruptionListener in interface InterruptionContext

Parameters:

listener - is ignored.

getMemoryModel

public MemoryModel getMemoryModel()

This implementation returns the memory model, specified by the argument of the corresponding constructor, or Arrays.SystemSettings.globalMemoryModel() if the constructor without arguments was used.

Specified by:

getMemoryModel in interface ArrayMemoryContext

Returns:

the desired memory model.

getMemoryModel

public MemoryModel getMemoryModel(Class<?> elementType)

This implementation returns mm.isElementTypeSupported(elementType) ? mm : SimpleMemoryModel.getInstance(), where mm is the result of getMemoryModel() method.

Specified by:

getMemoryModel in interface ArrayMemoryContext

Parameters:

elementType - the required element type.

Returns:

the desired memory model.

getMemoryModel

public MemoryModel getMemoryModel(String settings)

This implementation calls getMemoryModel() and returns its result.

Specified by:

getMemoryModel in interface ArrayMemoryContext

Parameters:

settings - additional desires about the required memory model.

Returns:

the desired memory model.

Throws:

NullPointerException - if the argument is null.

getThreadPoolFactory

public ThreadPoolFactory getThreadPoolFactory()

This implementation returns an instance of DefaultThreadPoolFactory.

Specified by:

getThreadPoolFactory in interface ArrayThreadPoolContext

Returns:

the desired thread tool factory.

updateProgress

public void updateProgress(double readyPart,
 boolean force)

This implementation calls updateStatus(String, boolean) with the first argument alike Math.round(readyPart*100)+"%" and the second argument force.

Specified by:

updateProgress in interface ProgressUpdater

Parameters:

readyPart - the part of calculations that is already done (from 0.0 to 1.0).

force - whether this information must be shown always (true) or may be lost (false).

updateStatus

public void updateStatus(String message)

This implementation calls updateStatus(message, true).

Specified by:

updateStatus in interface StatusUpdater

Parameters:

message - some information message.

updateStatus

public void updateStatus(String message,
 boolean force)

This implementation does nothing.

Specified by:

updateStatus in interface StatusUpdater

Parameters:

message - some information message.

force - whether this information must be shown always (true) or may be lost (false).