vgrid.task
Interface Task

All Superinterfaces:

java.io.Serializable

All Known Implementing Classes:

AbstractTask, DonauTaskRenamed, EnnsTaskRenamed, NullTask, TestExceptionTask, TestTask, VeryActiveTestTask

public interface Task
extends java.io.Serializable

A vgrid task. If your distributed program implements the task interface it can be run within the vgrid framework.

A task has to fulfill the following requirements:

• It has to be independend from other tasks that might execute at the same time.
• It must be executable in steps.
• It must be finished after a finite amount of steps

Technically:

• A task must have an unique id.
• It must be able to serialize and deserialize its current state.

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 msg) 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.

Method Detail

setId

void setId(java.lang.String setId)

Sets the tasks id.

Parameters:

setId - Unique id.

getId

java.lang.String getId()

Gets the tasks unique id.

Returns:

The id.

setExecutionHistory

void setExecutionHistory(java.lang.String msg)

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.

Parameters:

msg - The message to be reported.

getExecutionHistory

java.lang.String getExecutionHistory()

Returns the execution history of the task.

Returns:

The execution history.

takeOneStep

void takeOneStep()
                 throws java.lang.Exception

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

Throws:

java.lang.Exception

isFinished

boolean isFinished()

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

Returns:

True if the task is finished.

toStateString

java.lang.String toStateString()

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

Returns:

A string containing a description of the state of task.