vgrid.task
Class NullTask

java.lang.Object
  vgrid.task.NullTask

All Implemented Interfaces:

java.io.Serializable, Task

public class NullTask
extends java.lang.Object
implements Task

A task that does nothing on the client but to sleep for a certain amount of time. It gets deployed by the server if no other tasks are avaylable. The client creates its own NullTask if it cannot become a task from the server.

See Also:

Serialized Form

Field Summary

static java.lang.String

ID

Constructor Summary

NullTask()

NullTask(java.lang.String description, int timeout)

Method Summary

java.lang.String	getExecutionHistory() Returns the execution history of the task.
java.lang.String	getId() Gets the tasks unique id.
boolean	isFinished() Indicates that the task is finished.
void	setExecutionHistory(java.lang.String setId) Sets the tasks execution history.
void	setId(java.lang.String setId) Sets the tasks id.
void	takeOneStep() Executes one step of the task.
java.lang.String	toStateString() Should produce some info about the task and its current state.

Methods inherited from class java.lang.Object

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

Field Detail

ID

public static final java.lang.String ID

See Also:

Constant Field Values

Constructor Detail

NullTask

public NullTask()

NullTask

public NullTask(java.lang.String description,
                int timeout)

Method Detail

setId

public void setId(java.lang.String setId)

Description copied from interface: Task

Sets the tasks id.

Specified by:

setId in interface Task

Parameters:

setId - Unique id.

getId

public java.lang.String getId()

Description copied from interface: Task

Gets the tasks unique id.

Specified by:

getId in interface Task

Returns:

The id.

takeOneStep

public void takeOneStep()

Description copied from interface: Task

Executes one step of the task. Execution of this method should bring the task closer to termination.

Specified by:

takeOneStep in interface Task

isFinished

public boolean isFinished()

Description copied from interface: Task

Indicates that the task is finished. A task must finish after a finite amount of steps.

Specified by:

isFinished in interface Task

Returns:

True if the task is finished.

toStateString

public java.lang.String toStateString()

Description copied from interface: Task

Should produce some info about the task and its current state. Is used in the client GUI.

Specified by:

toStateString in interface Task

Returns:

A string containing a description of the state of task.

getExecutionHistory

public java.lang.String getExecutionHistory()

Description copied from interface: Task

Returns the execution history of the task.

Specified by:

getExecutionHistory in interface Task

Returns:

The execution history.

setExecutionHistory

public void setExecutionHistory(java.lang.String setId)

Description copied from interface: Task

Sets the tasks execution history. Typically this method is used by the client to inform the vendor what happend during execution. If an exception occures dureing execution the vendor finds the execution stack here.

Specified by:

setExecutionHistory in interface Task

Parameters:

setId - The message to be reported.