visad
Class ActionImpl

java.lang.Object
  visad.ActionImpl

All Implemented Interfaces:

Runnable, EventListener, Action, ThingChangedListener

Direct Known Subclasses:

CellImpl, DisplayImpl, FormulaVar

public abstract class ActionImpl
extends Object
implements Action, Runnable

ActionImpl is the abstract superclass for runnable threads that need to be notified when ThingReference objects change.

ActionImpl is the superclass of DisplayImpl and CellImpl.

ActionImpl is not Serializable and should not be copied between JVMs.

Field Summary

static boolean	TRACE_STACK
static boolean	TRACE_TIME Indicates whether we print out the trace from where an action is invoked and print its run time

Constructor Summary

ActionImpl(String name)
construct an ActionImpl

Method Summary

void	addReference(ThingReference ref) Creates a link to a ThingReference.
boolean	checkTicks()
void	disableAction() disable activity in this ActionImpl and if necessary wait for end of current doAction() call
abstract void	doAction() abstract method that implements activity of this ActionImpl
void	enableAction() enable activity in this ActionImpl and trigger any pending activity
ReferenceActionLink	findReference(ThingReference ref) Returns the link associated with a ThingReference.
Thread	getCurrentActionThread() return Thread currently active in run() method of this ActionImpl, or null is run() is not active
Vector	getLinks()
String	getName()
static int	getTaskCount() return the number of tasks in the threadpool queue
static void	printPool()
void	removeAllReferences() delete all links to ThingReferences
void	removeReference(ThingReference ref) Removes a link to a ThingReference.
void	run() invoked by a Thread from the ThreadPool whenever there is a request for activity in this ActionImpl
boolean	setEnabled(boolean enable) Set the "enabled" state of this action.
void	setName(String name) change the name of this Action
static void	setThreadPoolMaximum(int num) increase the maximum number of Threads allowed in the ThreadPool
void	stop() stop activity in this ActionImpl
static void	stopThreadPool() destroy all threads after they've drained the job queue
boolean	thingChanged(ThingChangedEvent e) a linked ThingReference has changed, requesting activity in this ActionImpl
void	waitForTasks() wait for all queued tasks in ThreadPool to finish

Methods inherited from class java.lang.Object

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

Field Detail

TRACE_TIME

public static final boolean TRACE_TIME

Indicates whether we print out the trace from where an action is invoked and print its run time

TRACE_STACK

public static final boolean TRACE_STACK

Constructor Detail

ActionImpl

public ActionImpl(String name)

construct an ActionImpl

Parameters:

name - - String name, used only for debugging

Method Detail

getTaskCount

public static int getTaskCount()

return the number of tasks in the threadpool queue

Returns:

number of queued and active tasks

printPool

public static void printPool()

stopThreadPool

public static void stopThreadPool()

destroy all threads after they've drained the job queue

setThreadPoolMaximum

public static void setThreadPoolMaximum(int num)
                                 throws Exception

increase the maximum number of Threads allowed in the ThreadPool

Parameters:

num - - new maximum number of Threads in ThreadPool

Throws:

Exception - - num is less than previous maximum

stop

public void stop()

stop activity in this ActionImpl

checkTicks

public boolean checkTicks()

Returns:

boolean that is disjunction (or) of flags saved in setTicks() calls to each linked ReferenceActionLink

enableAction

public void enableAction()

enable activity in this ActionImpl and trigger any pending activity

disableAction

public void disableAction()

disable activity in this ActionImpl and if necessary wait for end of current doAction() call

setEnabled

public boolean setEnabled(boolean enable)

Set the "enabled" state of this action. This may be used in code like the following to ensure that the action has the same "enabled" state on leaving the code as it did on entering it:

 ActionImpl action = ...;
 boolean wasEnabled = action.setEnabled(false);
 ...
 action.setEnabled(wasEnabled);
 

Parameters:

enable - The new "enabled" state for this action.

Returns:

The previous "enabled" state of this action.

getCurrentActionThread

public Thread getCurrentActionThread()

return Thread currently active in run() method of this ActionImpl, or null is run() is not active

Returns:

currently active thread or null

run

public void run()

invoked by a Thread from the ThreadPool whenever there is a request for activity in this ActionImpl

Specified by:

run in interface Runnable

doAction

public abstract void doAction()
                       throws VisADException,
                              RemoteException

abstract method that implements activity of this ActionImpl

Throws:

VisADException - a VisAD error occurred

RemoteException - an RMI error occurred

thingChanged

public boolean thingChanged(ThingChangedEvent e)
                     throws VisADException,
                            RemoteException

a linked ThingReference has changed, requesting activity in this ActionImpl

Specified by:

thingChanged in interface ThingChangedListener

Parameters:

e - ThingChangedEvent for change to ThingReference

Returns:

true if the ThingReference changed

Throws:

VisADException - a VisAD error occurred

RemoteException - an RMI error occurred

waitForTasks

public void waitForTasks()

wait for all queued tasks in ThreadPool to finish

addReference

public void addReference(ThingReference ref)
                  throws ReferenceException,
                         RemoteVisADException,
                         VisADException,
                         RemoteException

Creates a link to a ThingReference. Note that this method causes this object to register itself with the ThingReference.

Specified by:

addReference in interface Action

Parameters:

ref - The ThingReference to which to create the link. Subsequent invocation of thingChanged(ThingChangedEvent) causes invocation of ref.acknowledgeThingChanged(this) . This method invokes ref.addThingChangedListener(this, ...).

Throws:

RemoteVisADException - if the reference isn't a ThingReferenceImpl.

ReferenceException - if the reference has already been added.

VisADException - if a VisAD failure occurs.

RemoteException - if a Java RMI failure occurs.

See Also:

thingChanged(ThingChangedEvent), ThingReference.addThingChangedListener(ThingChangedListener, long)

removeReference

public void removeReference(ThingReference ref)
                     throws VisADException,
                            RemoteException

Removes a link to a ThingReference.

This implementation invokes findReference(ThingReference).

Specified by:

removeReference in interface Action

Parameters:

ref - The reference to be removed.

Throws:

RemoteVisADException - if the reference isn't a ThingReferenceImpl.

ReferenceException - if the reference isn't a part of this instance.

VisADException - if a VisAD failure occurs.

RemoteException - if a Java RMI failure occurs.

removeAllReferences

public void removeAllReferences()
                         throws VisADException,
                                RemoteException

delete all links to ThingReferences

Specified by:

removeAllReferences in interface Action

Throws:

RemoteException

VisADException

findReference

public ReferenceActionLink findReference(ThingReference ref)
                                  throws VisADException

Returns the link associated with a ThingReference.

Parameters:

ref - The reference to find.

Returns:

The link associated with the reference.

Throws:

ReferenceException - if the argument is null.

VisADException - if the argument is null.

getLinks

public Vector getLinks()

Returns:

Vector of linked ReferenceActionLinks

getName

public String getName()

Specified by:

getName in interface Action

Returns:

String name of this Action

setName

public void setName(String name)

change the name of this Action

Parameters:

name - new String name