Class: Couchbase::Datastructures::CouchbaseQueue

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/couchbase/datastructures/couchbase_queue.rb

Overview

A CouchbaseQueue is implements FIFO queue with Enumerable interface and backed by Collection document (more specifically a JSON array).

Note: sets are restricted to containing primitive types only due to server-side comparison restrictions.

Instance Method Summary collapse

Constructor Details

#initialize(id, collection, options = Options::CouchbaseQueue.new) ⇒ CouchbaseQueue

Create a new List, backed by the document identified by id in collection.

Parameters:

  • id (String) —

    the id of the document to back the queue.

  • collection (Collection) —

    the collection through which to interact with the document.

  • options (Options::CouchbaseList) (defaults to: Options::CouchbaseQueue.new) —

    customization of the datastructure



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# File 'lib/couchbase/datastructures/couchbase_queue.rb', line 35

def initialize(id, collection, options = Options::CouchbaseQueue.new)
  @id = id
  @collection = collection
  @options = options
  @cas = 0
  @observability = @collection.instance_variable_get(:@observability)
end

Instance Method Details

#clear(parent_span: nil) ⇒ Object

Removes all elements from the queue



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# File 'lib/couchbase/datastructures/couchbase_queue.rb', line 89

def clear(parent_span: nil)
  @observability.record_operation(Observability::OP_QUEUE_CLEAR, parent_span, self) do |obs_handler|
    options = @options.remove_options.clone
    options.parent_span = obs_handler.op_span
    @collection.remove(@id, options)
    nil
  rescue Error::DocumentNotFound
    nil
  end
end

#each(parent_span: nil) {|item| ... } ⇒ CouchbaseQueue, Enumerable

Calls the given block once for each element in the queue, passing that element as a parameter.

Yield Parameters:

  • item (Object)

Returns:



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# File 'lib/couchbase/datastructures/couchbase_queue.rb', line 48

def each(parent_span: nil, &)
  if block_given?
    current = @observability.record_operation(Observability::OP_QUEUE_EACH, parent_span, self) do |obs_handler|
      options = @options.get_options.clone
      options.parent_span = obs_handler.op_span
      result = @collection.get(@id, options)
      @cas = result.cas
      result.content
    rescue Error::DocumentNotFound
      @cas = 0
      []
    end
    current.each(&)
    self
  else
    enum_for(:each, parent_span: parent_span)
  end
end

#empty?(parent_span: nil) ⇒ Boolean

Returns true if queue is empty

Returns:

  • (Boolean) —

    returns true if queue is empty



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# File 'lib/couchbase/datastructures/couchbase_queue.rb', line 84

def empty?(parent_span: nil)
  size(parent_span: parent_span).zero?
end

#length(parent_span: nil) ⇒ Integer Also known as: size

Returns the number of elements in the queue.

Returns:

  • (Integer) —

    returns the number of elements in the queue.



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# File 'lib/couchbase/datastructures/couchbase_queue.rb', line 68

def length(parent_span: nil)
  @observability.record_operation(Observability::OP_QUEUE_LENGTH, parent_span, self) do |obs_handler|
    options = @options.lookup_in_options.clone
    options.parent_span = obs_handler.op_span
    result = @collection.lookup_in(@id, [
                                     LookupInSpec.count(""),
                                   ], options)
    result.content(0)
  rescue Error::DocumentNotFound
    0
  end
end

#pop(parent_span: nil) ⇒ Object? Also known as: deq, shift

Retrieves object from the queue

Returns:

  • (Object, nil) —

    queue entry or nil



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# File 'lib/couchbase/datastructures/couchbase_queue.rb', line 123

def pop(parent_span: nil)
  @observability.record_operation(Observability::OP_QUEUE_POP, parent_span, self) do |obs_handler|
    obj, cas = begin
      options = @options.lookup_in_options.clone
      options.parent_span = obs_handler.op_span
      result = @collection.lookup_in(@id, [
                                       LookupInSpec.get("[-1]"),
                                     ], @options.lookup_in_options)
      [
        result.exists?(0) ? result.content(0) : nil,
        result.cas,
      ]
    end
    begin
      options = Options::MutateIn.new(
        parent_span: obs_handler.op_span,
        cas: cas,
      )
      @collection.mutate_in(@id, [
                              MutateInSpec.remove("[-1]"),
                            ], options)
    end
    obj
  rescue Error::CasMismatch
    retry
  rescue Error::DocumentNotFound, Error::PathNotFound
    nil
  end
end

#push(obj, parent_span: nil) ⇒ CouchbaseQueue Also known as: enq, <<

Adds the given value to the queue

Parameters:

  • obj (Object)

Returns:



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# File 'lib/couchbase/datastructures/couchbase_queue.rb', line 104

def push(obj, parent_span: nil)
  @observability.record_operation(Observability::OP_QUEUE_PUSH, parent_span, self) do |obs_handler|
    options = @options.mutate_in_options.clone
    options.parent_span = obs_handler.op_span
    @collection.mutate_in(@id, [
                            MutateInSpec.array_prepend("", [obj]),
                          ], options)
  rescue Error::PathExists
    # ignore
  end
  self
end