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
· 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.
Finished
· boolean, read-only
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.
topInert
· boolean, read-only
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.
topLastErrorHtml
· 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.
topLastErrorText
· 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.
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.
topLastMethodSuccess
· 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.
topLive
· boolean, read-only
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.
topNumTasks
· integer, read-only
The number of tasks contained within the task chain.
topStatus
· string, read-only
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.
StatusInt
· integer, read-only
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.
StopOnFailedTask
· boolean
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.
topVerboseLogging
· 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.
topVersion
· string, read-only
Methods
Append
· Returns Boolean (true for success, false for failure).
· task Task
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.
Cancel
· Returns Boolean (true for success, false for failure).
GetTask
· Returns a Task
· index Number
Run
· Returns Boolean (true for success, false for failure).
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.
topSleepMs
· Does not return anything (returns Undefined).
· numMs Number
Convenience method to force the calling thread to sleep for a number of milliseconds.
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