Package ikr.simlib.entities.queues

Queues

See: Description

Class Summary

Class	Description
BoundedFIFOQueue	This class implements a bounded FIFO (First In First Out) queue, i.e., it has a finite buffer size.
BoundedLIFOQueue	This class implements a bounded LIFO (Last In First Out) queue, i.e., it has a finite buffer size.
FIFODropTailQueue	Deprecated
QueuingEntity	QueuingEntity is the entity that integrates a queuing discipline managing some buffer into the simulation.
SingleServerQueue	Deprecated
StdSingleServerQueue	Deprecated
UnboundedFIFOQueue	This class implements an unbounded FIFO (First In First Out) queue, i.e., it has an infinite buffer size.
UnboundedLIFOQueue	This class implements an unbounded LIFO (Last In First Out) queue, i.e., it has an infinite buffer size.

Package ikr.simlib.entities.queues Description

Queues

Queues that are based on the base class QueuingEntity which is derived from Entity can store any kind of message. QueuingEntity has four special derivatives, namely BoundedFIFOQueue, UnboundedFIFOQueue, BoundedLIFOQueue and UnboundedLIFOQueue. The first two represent a FIFO queues (First In First Out), whereas the latter two represents a LIFO queue (Last In First Out).
The lengths of a queue is measured in units (information units, e. g. bytes). A unit corresponds to the length specified in the member length of Message and is also the basis to determine whether a bounded queue is full. Nevertheless, the length of a queue in number of packets is also remembered by List<> in which the messages are stored. The different kinds of lengths can be retrieved by queue.getQDisc().getCurrentNumberOfUnits() and queue.getQDisc().getCurrentNumberOfMessages(), respectively.

• The communication with the preceding or succeeding model component is processed via an input port (class InputPort) or via an output port (class OutputPort).
• In QueuingEntity messages that arrive at the input port are buffered including their arrival time with the method put() (if there is enough room in the queue).
• Simultaneously a message for the succeeding model component is offered.
• If there is not enough buffer space in the queue to store the currently arriving message, a BoundedFIFOQueue will drop the message, whereas a BoundedLIFOQueue will drop as many messages from the head of the queue as necessary to store the arriving message. In case it is larger than the maximum allowed queue size, it is dropped immediately without deleting any messages from the queue.
• Upon request by the succeeding model component the method get() is used to retrieve the next message from the queue.
• Statistics are kept on
  • the waiting time in reference to waiting messages
  • the waiting time in reference to all passing messages (transfer time)
  • the queue length in number of units
  • the queue length in number of messages
  • the loss probability