Class AWS::SimpleWorkflow::DecisionTaskCollection
In: lib/aws/simple_workflow/decision_task_collection.rb
Parent: Object

Provides an interface to count, and receive decision tasks ({DecisionTask} objects) from the service.

## Counting

To get a count of decision tasks needing attention, call {count} with a task list name:

    domain.decision_tasks.count('my-task-list').to_i #=> 7

## Getting a single decision task

To process a single task use {poll_for_single_task}:

    domain.decision_tasks.poll_for_single_task('my-task-list') do |task|
      # this block is yielded to only if a task is found
      # within 60 seconds.
    end

At the end of the block, the decision task is auto-completed. If you prefer you can omit the block and `nil` or a {DecisionTask} will be returned.

    if task = domain.decision_tasks.poll_for_single_task('my-task-list')
      # you need to call complete! or the decision task will time out
      task.complete!
    end

## Polling for Tasks in a Loop

You can poll indefinitely for tasks in a loop with {poll}:

    domain.decision_tasks.poll('my-task-list') do |task|
      # yields once for every decision task found
    end

Just like the block form above, the decision task is auto completed at the end of the block. Please note, if you call `break` or `return` from inside the block, you MUST call {DecisionTask#complete!} or the task will timeout.

## Events and Decisions

Each decision task provides an enumerable collection of both new events ({DecisionTask#new_events}) and all events ({DecisionTask#events}).

Based on the events in the workflow execution history, you should call methods on the decision task. See {DecisionTask} for a complete list of decision methods.

Methods

Included Modules

Core::Model OptionFormatters

Attributes

domain  [R]  @return [Domain]

Public Class methods

Public Instance methods

Returns the number of decision tasks in the specified `task_list`.

    count = decision_tasks.count('task-list-name')
    count.truncated? #=> false
    count.to_i #=> 7

@note This operation is eventually consistent. The results are best

  effort and may not exactly reflect recent updates and changes.

@param [String] task_list Name of the task list to count

  decision tasks for.

@return [Count] Returns a {Count} object that specifies the number

  of decision tasks for the given task list.  This count will
  also indicate if the count was truncated.

Polls indefinitely for decision tasks. Each decision task found is yielded to the block. At the end of the block the decision task is auto-completed ({DecisionTask#complete!} is called).

    # yields once for each decision task found, indefinitely
    domain.decision_tasks.poll do |decision_task|
      # make decisions here
    end

@note If you to terminate the block (by calling `break` or `return`)

  then it is your responsibility to call #complete! on the decision
  task.

@param (see poll_for_single_task)

@option (see poll_for_single_task)

@yieldparam [DecisionTask] decision_task

@return [nil]

Polls the service for a single decision task. The service may hold the request for up to 60 seconds before responding.

    # try to get a single task, may return nil when no tasks available
    task = domain.decision_tasks.poll_for_single_task('task-list')
    if task
      # make decisions ...
      task.complete!
    end

You can optionally pass a block and that will only be yielded to when a decision task is available within the 60 seconds.

    domain.decision_tasks.poll_for_single_task('task-list') do |task|
       # make decisions
       # task.complete! is called for you at the end of the block
    end

With the block form you do not need to call complete! on the decision task. It will be called when the block exists.

@note If you are not using the block form you must call

  {DecisionTask#complete!} yourself or your decision task will
  timeout.

@param [String] task_list Specifies the task list to poll for

  decision tasks.

@param [Hash] options

@option options [String] :identity The identity of the decider

  requesting a decision task.  This will be recorded in the
  DecisionTaskStarted event in the workflow history.
  If `:identity` is not passed then the hostname and
  process id will be sent (e.g. "hostname:pid").

@option options [Boolean] :reverse_event_order (false) When true,

  the history events on the decision task will enumerate in
  reverse chronological order (newest events first).  By default
  the events are enumerated in chronological order (oldest first).

@option options [Integer] :event_batch_size (1000) When enumerating

  events on the decision task, multiple requests may be required
  to fetch all of the events.  You can specify the maximum number
  of events to request each time (must not be greater than 1000).

@yieldparam [DecisionTask] decision_task

@return [DecisionTask,nil] Returns a decision task or `nil`. If

  a block was passed then `nil` is always returned.  If a block
  is not passed, then `nil` or a {DecisionTask} will be returned.

[Validate]