AGSObservableOperation Class Reference

Description

Base class for operations. This adds the ability to register a listener to the AGSOperationBase. It also adds the concept of an error and a result.

Since

100

Inheritance diagram for AGSObservableOperation:

Instance Methods
(void)	- cancel
(void)	- didComplete:
(void)	- doCancel
(void)	- doExecute
(void)	- doneExecuting
(void)	- execute
(BOOL)	- isRegisteredListener:
(void)	- registerListener:forCompletion:
(void)	- unregisterListener:

Properties
BOOL	canceled
NSError *	error
void(^	internalCompletion )(void)
id	result
BOOL	startAsynchronously
AGSOperationState	state

Method Documentation

cancel

- (void) cancel

Cancels the operation.

Since

100

didComplete:

- (void) didComplete:

(BOOL)

everStarted

Subclasses should override if they want to run some code once the operation is completed. This function is guaranteed to only be called once. everStarted will be NO if the operation was canceled before it could be started.

Since

100

Provided by category AGSOperationBase(ForSubclassEyesOnly).

doCancel

- (void) doCancel

Subclasses can override to do the actual work to cancel the operation. Once cancel is complete, call doneExecuting. For operations that do not do all of their work in doExecute, it makes sense to override this and cancel any network connections, etc. Then when the cancel is complete, you call doneExecuting. For operations where the work is all done in doExecute they shouldn't need to override this, you should just check the isCanceled property throughout the execution of the operation and if it is canceled then call doneExecuting and return.

Since

100

Provided by category AGSOperationBase(ForSubclassEyesOnly).

doExecute

- (void) doExecute

Subclasses should override to do the actual execution of the operation. Once done, call doneExecuting.

Since

100

Provided by category AGSOperationBase(ForSubclassEyesOnly).

doneExecuting

- (void) doneExecuting

Subclasses should call this when they are done executing or done cancelling.

Since

100

Provided by category AGSOperationBase(ForSubclassEyesOnly).

execute

- (void) execute

Starts the operation

Since

100

isRegisteredListener:

- (BOOL) isRegisteredListener:

(id)

listener

Returns whether or not the specified object is a registered as a listener to this operation.

Since

100

registerListener:forCompletion:

- (void) registerListener:		(id)	listener
forCompletion:		(void(^)(id __nullable result, NSError *__nullable error))	completion

Adds a completion handler to the operation for the specified listener. If you are using this option, you can unregister a completionHandler for a listener if you need to. When there are no more listeners the operation will be canceled automatically.

Parameters

listener	The listener to add the completion block for.
completion	The completion handler to be called.

Since

100

unregisterListener:

- (void) unregisterListener:

(id)

listener

Removes the registered completion handler to the operation for the specified listener. When there are no more listeners the operation will be canceled automatically. To avoid any potential retain cycles the listener is not retained by the operation. Unregistering is just the way to tell the operation that you no longer care about getting the completion event.

Parameters

listener

The listener to unregister

Since

100

Property Documentation

canceled

- (BOOL) canceled

readnonatomicassigninherited

Whether or not cancel has been called on the operation. "Canceled" is a modifier on the current state since:

1. The operation can be still "executing" until the cancel takes effect.
2. An operation can be canceled and in a completed state at the same time.

   Since

   100

error

- (NSError*) error

readnonatomicstrong

The error, if any, that occurred.

Since

100

internalCompletion

- (void(^ internalCompletion) (void))

readwritenonatomiccopyinherited

The block the operation will call to signify to the operation queue that the operation is complete. This block is reserved for use by the AGSOperationQueue. Do not assign your own block to this.

Since

100

result

- (id) result

readnonatomicstrong

The results of an operation. It will be of type NSDictionary when the result is json, AGSImage when the result is an image, and NSData when anything else.

Since

100

startAsynchronously

- (BOOL) startAsynchronously

readwritenonatomicassigninherited

Subclasses can set this if they want to be started asynchronously or not. If an operation does most or all of it's work in doExecute it should set this to YES. If an operation returns quickly from doExecute and does all of it's work on a different queue then this value should be NO. The default value is YES.

Provided by category AGSOperationBase(ForSubclassEyesOnly).

state

- (AGSOperationState) state

readnonatomicassigninherited

The current state of the operation.

Since

100