Package rife.workflow

Class Workflow

java.lang.Object

rife.workflow.Workflow

public class Workflow
extends Object

Runs work and dispatches events to work that is paused.

Note that this workflow executes the work, but doesn't create a new thread for itself. When a workflow is used, you should take the necessary steps to keep the application running for as long as you need the work to be available.

Events are delivered to the registered listeners before any work that is paused for them is resumed. Events that work triggers after being woken up are therefore always delivered to listeners after the event that woke the work up. No ordering is guaranteed between events that are triggered concurrently from independent threads.

Since:

1.0

API Note:

The workflow engine is in a BETA STAGE and might still change.

Constructor Summary

Constructors

Constructor	Description
Workflow()	Creates a new workflow instance with a cached thread pool.
Workflow(ExecutorService executor)	Creates a new workflow instance with a provided executor.
Workflow(ExecutorService executor, HierarchicalProperties properties)	Creates a new workflow instance.
Workflow(HierarchicalProperties properties)	Creates a new workflow instance with a provided parent properties.

Method Summary

Modifier and Type	Method	Description
void	addErrorListener(ErrorListener listener)	Adds a new error listener that will be notified when work fails with an exception.
void	addListener(EventListener listener)	Adds a new event listener.
void	inform(Object type)	Convenience method that informs about an event in a workflow.
void	inform(Object type, Object data)	Convenience method that informs about an event in a workflow with associated data.
void	inform(Event event)	Informs about an event that wakes up work if it is paused for the event type.
HierarchicalProperties	properties()	Retrieves the hierarchical properties for this workflow instance.
void	removeErrorListener(ErrorListener listener)	Removes an error listener.
void	removeListener(EventListener listener)	Removes an event listener.
Workflow	start(Class<? extends Work> klass)	Starts the execution of a new work instance.
Workflow	start(Work work)	Starts the execution of a new work instance.
void	trigger(Object type)	Convenience method that triggers an event in a workflow.
void	trigger(Object type, Object data)	Convenience method that triggers an event in a workflow with associated data.
void	trigger(Event event)	Triggers an event that wakes up work that is paused for the event type.
void	waitForNoWork()	Causes the calling thread to wait until no more work is running.
boolean	waitForPausedWork()	Causes the calling thread to wait until work is paused for events.

Methods inherited from class java.lang.Object

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

Constructor Details

Workflow

public Workflow()

Creates a new workflow instance with a cached thread pool.

Since:

1.0

Workflow

public Workflow(ExecutorService executor)

Creates a new workflow instance with a provided executor.

Parameters:

executor - the executor to use for running the work

Since:

1.0

Workflow

public Workflow(HierarchicalProperties properties)

Creates a new workflow instance with a provided parent properties.

Parameters:

properties - the parent hierarchical properties

Since:

1.0

Workflow

public Workflow(ExecutorService executor,
 HierarchicalProperties properties)

Creates a new workflow instance.

Parameters:

executor - the executor to use for running the work

properties - the parent hierarchical properties

Since:

1.0

Method Details

properties

public HierarchicalProperties properties()

Retrieves the hierarchical properties for this workflow instance.

Returns:

this workflow's collection of hierarchical properties

Since:

1.0

start

public Workflow start(Class<? extends Work> klass)

Starts the execution of a new work instance.

Parameters:

klass - the work class whose instance that should be executed, the class should extend Work

Since:

1.0

start

public Workflow start(Work work)

Starts the execution of a new work instance.

Parameters:

work - the work that should be executed

Returns:

this workflow instance

Since:

1.0

inform

public void inform(Object type)

Convenience method that informs about an event in a workflow.

Parameters:

type - the type of the event

Since:

1.0

See Also:

• inform(Object, Object)
• inform(Event)

inform

public void inform(Object type,
 Object data)

Convenience method that informs about an event in a workflow with associated data.

Parameters:

type - the type of the event

data - the data that will be sent with the event

Since:

1.0

See Also:

• inform(Object)
• inform(Event)

inform

public void inform(Event event)

Informs about an event that wakes up work if it is paused for the event type.

If events are informed about and no work is ready to consume them, they will be lost. This is different from events being triggered.

Parameters:

event - the event

Since:

1.0

See Also:

• trigger(Object)
• trigger(Object, Object)

trigger

public void trigger(Object type)

Convenience method that triggers an event in a workflow.

Parameters:

type - the type of the event

Since:

1.0

See Also:

• trigger(Object, Object)
• trigger(Event)

trigger

public void trigger(Object type,
 Object data)

Convenience method that triggers an event in a workflow with associated data.

Parameters:

type - the type of the event

data - the data that will be sent with the event

Since:

1.0

See Also:

• trigger(Object)
• trigger(Event)

trigger

public void trigger(Event event)

Triggers an event that wakes up work that is paused for the event type.

If events are triggered, and no work is ready to consume them, they will be queued up until the first available work arrives.

Parameters:

event - the event

Since:

1.0

See Also:

• trigger(Object)
• trigger(Object, Object)

waitForPausedWork

public boolean waitForPausedWork()
                          throws InterruptedException

Causes the calling thread to wait until work is paused for events.

This method also returns when no active work remains that could still pause, for instance when all work has finished or has failed with an exception. The returned value indicates which of the two situations occurred.

Returns:

true when work is paused for events; or

false when no active work remains that could still pause

Throws:

InterruptedException - when the current thread is interrupted

Since:

1.0

waitForNoWork

public void waitForNoWork()
                   throws InterruptedException

Causes the calling thread to wait until no more work is running.

Throws:

InterruptedException - when the current thread is interrupted

Since:

1.0

addListener

public void addListener(EventListener listener)

Adds a new event listener.

Parameters:

listener - the event listener that will be added

Since:

1.0

See Also:

• removeListener(rife.workflow.EventListener)

removeListener

public void removeListener(EventListener listener)

Removes an event listener.

Parameters:

listener - the event listener that will be removed

Since:

1.0

See Also:

• addListener(rife.workflow.EventListener)

addErrorListener

public void addErrorListener(ErrorListener listener)

Adds a new error listener that will be notified when work fails with an exception.

When no error listeners have been registered, work failures will be logged to the rife.workflow logger instead.

Parameters:

listener - the error listener that will be added

Since:

1.10

See Also:

• removeErrorListener(rife.workflow.ErrorListener)
• ErrorListener

removeErrorListener

public void removeErrorListener(ErrorListener listener)

Removes an error listener.

Once the listener has been removed, it will not be notified of any work failures anymore.

Parameters:

listener - the error listener that will be removed

Since:

1.10

See Also:

• addErrorListener(rife.workflow.ErrorListener)
• ErrorListener