ai.grakn.engine.backgroundtasks

Interface StateStorage

All Known Implementing Classes:

GraknStateStorage, InMemoryStateStorage

public interface StateStorage

Method Summary

Modifier and Type	Method and Description
TaskState	getState(String id) This is a copy of the internal TaskState object.
Set<javafx.util.Pair<String,TaskState>>	getTasks(TaskStatus taskStatus, String taskClassName, String createdBy, int limit, int offset) Return a Set of Pairs of tasks that match any of the criteria.
String	newState(String taskName, String createdBy, Date runAt, Boolean recurring, long interval, org.json.JSONObject configuration) Create a new task state and store it, returning an ID to later access this task state.
void	updateState(String id, TaskStatus status, String statusChangeBy, String executingHostname, Throwable failure, String checkpoint, org.json.JSONObject configuration) Used to update task state.

Method Detail

newState

String newState(String taskName,
                String createdBy,
                Date runAt,
                Boolean recurring,
                long interval,
                org.json.JSONObject configuration)

Create a new task state and store it, returning an ID to later access this task state.

Parameters:

taskName - String class name of object implementing the BackgroundTask interface. This must not be null.

createdBy - String of who is creating this new state. This must not be null.

runAt - Date when should this task be executed. This must not be null.

recurring - Boolean marking if this task should be run again after it has finished executing successfully. This must not be null.

interval - If a task is marked as recurring, this represents the time delay between the next executing of this task. This must not be null.

configuration - A JSONObject instance containing configuration and optionally data for the task. This is an optional parameter and may be set to null to not pass any configuration (task.start() will get an initialised but empty JSONObject).

Returns:

String form of the task id, which can be use later to update or retrieve the task state. Null if task could not be created of mandatory fields were omitted.

updateState

void updateState(String id,
                 TaskStatus status,
                 String statusChangeBy,
                 String executingHostname,
                 Throwable failure,
                 String checkpoint,
                 org.json.JSONObject configuration)

Used to update task state. With the exception of @id any other fields may individually be null, however all parameters cannot be null at the same time. Setting any of the parameters to null indicates that their values should not be changed.

Parameters:

id - ID of task to update, this must not be null.

status - New status of task, may be null.

statusChangeBy - String identifying caller, may be null.

executingHostname - String hostname of engine instance scheduling/executing this task. May be null.

failure - Throwable to store any exceptions that occurred during executing. May be null.

checkpoint - String to store task checkpoint, may be null.

getState

TaskState getState(String id)

This is a copy of the internal TaskState object. It is guaranteed to be correct at the time of call, however the actual internal state may change at any time after.

Parameters:

id - String id of task.

Returns:

TaskState object or null if no TaskState with this id could be found.

getTasks

Set<javafx.util.Pair<String,TaskState>> getTasks(TaskStatus taskStatus,
                                                 String taskClassName,
                                                 String createdBy,
                                                 int limit,
                                                 int offset)

Return a Set of Pairs of tasks that match any of the criteria. The first value of the Pair is the task id, whilst the second is the TaskState. Parameters may be set to null to not match against then (rather than to match null values), if *all* parameters are null then all known tasks in the system are returned.

Parameters:

taskStatus - See TaskStatus enum.

taskClassName - String containing task class name. See TaskState.

createdBy - String containing created by. See TaskState.

limit - Limit the returned result set to @limit amount of entries.

offset - Use in conjunction with @limit for pagination.

Returns:

Set> of task IDs and corresponding TaskState *copies*.