TaskChain Node.js Reference Documentation

TaskChain

Current Version: 10.1.2

Represents a chain of asynchronous tasks to be run in sequence in a background thread.

Object Creation

var obj = new chilkat.TaskChain();

Properties

DebugLogFilePath
DebugLogFilePath
· string

If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.

Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.

Possible causes of hangs include:

  • A timeout property set to 0, indicating an infinite timeout.
  • A hang occurring within an event callback in the application code.
  • An internal bug in the Chilkat code causing the hang.

More Information and Examples
top
Finished
Finished
· boolean, read-only
Introduced in version 9.5.0.52

true if the task status is "canceled", "aborted", or "completed". A task chain can only reach the "canceled" status if it was activated via the Run method, made it onto the internal thread pool thread's queue, was waiting for a pool thread to become available, and was then canceled prior to the task actually starting.

top
Inert
Inert
· boolean, read-only
Introduced in version 9.5.0.52

true if the task status is "empty" or "loaded". When a task chain is inert, it has been loaded but is not scheduled to run yet.

top
LastErrorHtml
LastErrorHtml
· string, read-only

Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

top
LastErrorText
LastErrorText
· string, read-only

Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

top
LastErrorXml
LastErrorXml
· string, read-only

Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

top
LastMethodSuccess
LastMethodSuccess
· boolean

Indicates the success or failure of the most recent method call: true means success, false means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages.

top
Live
Live
· boolean, read-only
Introduced in version 9.5.0.52

true if the task status is "queued" or "running". When a task chain is live, it is either already running, or is on the thread pool thread's queue waiting for a thread to become available.

top
NumTasks
NumTasks
· integer, read-only
Introduced in version 9.5.0.52

The number of tasks contained within the task chain.

top
Status
Status
· string, read-only
Introduced in version 9.5.0.52

The current status of the task chain. Possible values are:

  • "empty" -- No tasks have yet been appended to the task chain.
  • "loaded" -- The task chain has been loaded (appended) with one or more task objects.
  • "queued" -- The task chain is in the thread pool's queue of tasks awaiting to be run.
  • "running" -- The task chain is currently running.
  • "canceled" -- The task chain was canceled before it entered the "running" state.
  • "aborted" -- The task chain was canceled while it was in the running state.
  • "completed" -- The task chain completed.

top
StatusInt
StatusInt
· integer, read-only
Introduced in version 9.5.0.52

The current status of the task as an integer value. Possible values are:

  • 1 -- "empty" -- No tasks have yet been appended to the task chain.
  • 2 -- "loaded" -- The task chain has been loaded (appended) with one or more task objects.
  • 3 -- "queued" -- The task chain is in the thread pool's queue of tasks awaiting to be run.
  • 4 -- "running" -- The task chain is currently running.
  • 5 -- "canceled" -- The task chain was canceled before it entered the "running" state.
  • 6 -- "aborted" -- The task chain was canceled while it was in the running state.
  • 7 -- "completed" -- The task chain completed.

top
StopOnFailedTask
StopOnFailedTask
· boolean
Introduced in version 9.5.0.52

If true then stops execution of the task chain if any individual task fails. Task failure is defined by the standard LastMethodSuccess property. If false, then all of the tasks in the chain will be run even if some fail. The default value of this property is true.

top
VerboseLogging
VerboseLogging
· boolean

If set to true, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is false. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

top
Version
Version
· string, read-only

Version of the component/library, such as "10.1.0"

More Information and Examples
top

Methods

Append
var status = Append(task);
· Returns Boolean (true for success, false for failure).
· task Task
Introduced in version 9.5.0.52

Appends a task to the task chain. Can fail if the task is already part of another chain. (A task can only be part of a single chain.)

Returns true for success, false for failure.

More Information and Examples
top
Cancel
var status = Cancel();
· Returns Boolean (true for success, false for failure).
Introduced in version 9.5.0.52

Cancels execution of the asynchronous task chain.

Returns true for success, false for failure.

top
GetTask
var ret_task = GetTask(index);
· Returns a Task
· index Number
Introduced in version 9.5.0.52

Returns the Nth task in the chain. The 1st task is at index 0.

Returns null on failure

top
Run
var status = Run([taskCompleted]);
· Returns Boolean (true for success, false for failure).
Introduced in version 9.5.0.52

If a taskCompleted callback function is passed in , then the task chain is started on Node's internal thread pool. Each task in the chain will run, one after the other. If no callback function is passed, the task chain runs synchronously.

Returns true for success, false for failure.

top
SleepMs
SleepMs(numMs);
· Does not return anything (returns Undefined).
· numMs Number
Introduced in version 9.5.0.52

Convenience method to force the calling thread to sleep for a number of milliseconds.

top