drcl.comp.queue
Class ActiveQueue

java.lang.Object
  drcl.DrclObj
      drcl.comp.Component
          drcl.comp.queue.ActiveQueue

All Implemented Interfaces:

java.lang.Cloneable, ObjectCloneable, ObjectDuplicable, java.io.Serializable

Direct Known Subclasses:

Queue, QueueFIFO

public abstract class ActiveQueue

extends Component

An ActiveQueue is a queue and it is designed to interact with a data pulling component. It accepts a null signal from the data pulling component which triggers a dequeue and the dequeued data is sent at the output@ port. If the queue is empty, this component remembers that the pulling component is available for receiving data, and when new data arrives, this component actively sends out the data at the output@ port without the pulling component having to do the pulling again. Multiple pullings when the queue is empty results in only one time of active sending.

See Also:

Serialized Form

Nested Class Summary

Nested classes inherited from class drcl.comp.Component

Component.Locks

Field Summary

static java.lang.String

OUTPUT_PORT_ID

Fields inherited from class drcl.comp.Component

FLAG_COMPONENT_NOTIFICATION, FLAG_DEBUG_ENABLED, FLAG_DIRECT_OUTPUT_ENABLED, FLAG_ENABLED, FLAG_ERROR_ENABLED, FLAG_EVENT_ENABLED, FLAG_GARBAGE_DISPLAY_ENABLED, FLAG_GARBAGE_ENABLED, FLAG_PORT_NOTIFICATION, FLAG_STARTED, FLAG_STOPPED, FLAG_TRACE_ENABLED, FLAG_UNDEFINED_START, id, infoPort, locks, name, parent, PortGroup_DEFAULT_GROUP, PortGroup_EVENT, PortGroup_SERVICE, Root, Trace_DATA, Trace_SEND

Constructor Summary

ActiveQueue()

ActiveQueue(java.lang.String id_)

Method Summary

abstract java.lang.Object	dequeue() Dequeues and returns the first object in the queue.
abstract java.lang.Object	enqueue(java.lang.Object obj_) Enqueues the object at the end of the queue
java.lang.Object	enqueueAt(java.lang.Object obj_, int pos_) Enqueues the object at the position specified.
java.lang.Object	firstElement() Retrieves but not dequeue the first object in the queue.
int	getAvailableSize() Returns the available size of the queue.
abstract int	getCapacity() Returns the capacity of the queue.
abstract int	getSize() Returns the current size of the queue.
void	increaseEnqueCount() Increases the enqueue counter, for diagnosis purpose.
java.lang.String	info() Returns information regarding this component.
java.lang.String	info(java.lang.String prefix_)
abstract boolean	isEmpty() Return true if the queue is empty.
abstract boolean	isFull() Return true if the queue is full.
java.lang.Object	lastElement() Retrieves but not remove the last object in the queue.
java.lang.Object	peekAt(int pos_) Retrieves but not dequeue the object at the position specified.
void	reset() Resets the component for being used anew.
java.lang.Object	retrieveAt(int pos_) Dequeues the object at the position specified.
abstract void	setCapacity(int capacity_) Sets the capacity of the queue.

Methods inherited from class drcl.comp.Component

addComponent, addComponent, addEventPort, addEventPort, addForkPort, addPort, addPort, addPort, addPort, addPort, addPort, addPort, addPort, addServerPort, addServerPort, cancelFork, connect, containsComponent, containsComponent, containsPort, debug, disconnectAll, disconnectAllPeers, disconnectAllPorts, drop, drop, duplicate, error, error, expose, exposeEventPorts, exposePort, exposePort, exposePort, exposePort, exposePort, findAvailable, findAvailable, findAvailable, fork, forkAt, getAllComponents, getAllPorts, getAllPorts, getAllWiresInside, getAllWiresInsideOut, getAllWiresOut, getComponent, getComponentFlag, getComponentFlag, getContract, getContractHT, getContractHT, getDebugFlagsInBinary, getDebugLevelNames, getID, getName, getParent, getPort, getPort, getRoot, getTime, iduplicate, isAncestorOf, isContainer, isDebugEnabled, isDebugEnabledAt, isDirectlyRelatedTo, isDirectOutputEnabled, isEnabled, isErrorNoticeEnabled, isEventExportEnabled, isGarbageDisplayEnabled, isGarbageEnabled, isPortRemovable, isStarted, isStopped, isTraceEnabled, lock, notify, notifyAll, operate, reboot, removeAll, removeAllComponents, removeAllPorts, removeAllPorts, removeComponent, removeComponent, removePort, removePort, removePort, resume, run, sduplicate, send, sendAt, setComponentFlag, setComponentFlag, setDebugEnabled, setDebugEnabled, setDebugEnabledAt, setDebugEnabledAt, setDebugEnabledAt, setDirectOutputEnabled, setDirectOutputEnabled, setEnabled, setErrorNoticeEnabled, setErrorNoticeEnabled, setEventExportEnabled, setEventExportEnabled, setExecutionBoundary, setGarbageDisplayEnabled, setGarbageDisplayEnabled, setGarbageEnabled, setGarbageEnabled, setID, setID, setName, setPort, setPort, setTraceEnabled, setTraceEnabled, sleepFor, sleepUntil, stop, toString, unexpose, unlock, useLocalForkManager, useLocalForkManager, wait

Methods inherited from class drcl.DrclObj

clone

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

OUTPUT_PORT_ID

public static final java.lang.String OUTPUT_PORT_ID

See Also:

Constant Field Values

Constructor Detail

ActiveQueue

public ActiveQueue()

ActiveQueue

public ActiveQueue(java.lang.String id_)

Method Detail

reset

public void reset()

Description copied from class: Component

Resets the component for being used anew. All the internal variables must be set to the initial state. All the ports and child components are reset as well.

Overrides:

reset in class Component

info

public java.lang.String info()

Description copied from class: Component

Returns information regarding this component. Subclasses should override this method to provide useful information at run time.

Overrides:

info in class Component

info

public java.lang.String info(java.lang.String prefix_)

increaseEnqueCount

public final void increaseEnqueCount()

Increases the enqueue counter, for diagnosis purpose.

enqueue

public abstract java.lang.Object enqueue(java.lang.Object obj_)

Enqueues the object at the end of the queue

Returns:

the object being dropped due to the enqueue; null otherwise.

enqueueAt

public java.lang.Object enqueueAt(java.lang.Object obj_,
                                  int pos_)

Enqueues the object at the position specified.

Returns:

the object being dropped due to the enqueue; null otherwise.

dequeue

public abstract java.lang.Object dequeue()

Dequeues and returns the first object in the queue.

Returns:

the object dequeued; null if position is not valid.

retrieveAt

public java.lang.Object retrieveAt(int pos_)

Dequeues the object at the position specified.

Returns:

the object dequeued; null if position is not valid.

peekAt

public java.lang.Object peekAt(int pos_)

Retrieves but not dequeue the object at the position specified.

Returns:

the object; null if position is not valid.

firstElement

public java.lang.Object firstElement()

Retrieves but not dequeue the first object in the queue.

Returns:

the object; null if queue is empty.

lastElement

public java.lang.Object lastElement()

Retrieves but not remove the last object in the queue.

Returns:

the object; null if queue is empty.

isFull

public abstract boolean isFull()

Return true if the queue is full.

isEmpty

public abstract boolean isEmpty()

Return true if the queue is empty.

setCapacity

public abstract void setCapacity(int capacity_)

Sets the capacity of the queue.

getCapacity

public abstract int getCapacity()

Returns the capacity of the queue.

getSize

public abstract int getSize()

Returns the current size of the queue.

getAvailableSize

public int getAvailableSize()

Returns the available size of the queue.