EDU.oswego.cs.dl.util.concurrent
Class Slot

java.lang.Object
  |
  +--EDU.oswego.cs.dl.util.concurrent.SemaphoreControlledChannel
        |
        +--EDU.oswego.cs.dl.util.concurrent.Slot
All Implemented Interfaces:
BoundedChannel, Channel, Puttable, Takable

public class Slot
extends SemaphoreControlledChannel

A one-slot buffer, using semaphores to control access. Slots are usually more efficient and controllable than using other bounded buffers implementations with capacity of 1.

Among other applications, Slots can be convenient in token-passing designs: Here. the Slot holds a some object serving as a token, that can be obtained and returned by various threads.

[ Introduction to this package. ]


Constructor Summary
Slot()
          Create a new Slot using default Semaphore implementations
Slot(java.lang.Class semaphoreClass)
          Create a buffer with the given capacity, using the supplied Semaphore class for semaphores.
 
Method Summary
 java.lang.Object peek()
          Return, but do not remove object at head of Channel, or null if it is empty.
 
Methods inherited from class EDU.oswego.cs.dl.util.concurrent.SemaphoreControlledChannel
capacity, offer, poll, put, size, take
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

Slot

public Slot(java.lang.Class semaphoreClass)
     throws java.lang.NoSuchMethodException,
            java.lang.SecurityException,
            java.lang.InstantiationException,
            java.lang.IllegalAccessException,
            java.lang.reflect.InvocationTargetException
Create a buffer with the given capacity, using the supplied Semaphore class for semaphores.

Throws:
java.lang.NoSuchMethodException - If class does not have constructor that intializes permits
java.lang.SecurityException - if constructor information not accessible
java.lang.InstantiationException - if semaphore class is abstract
java.lang.IllegalAccessException - if constructor cannot be called
java.lang.reflect.InvocationTargetException - if semaphore constructor throws an exception

Slot

public Slot()
Create a new Slot using default Semaphore implementations

Method Detail

peek

public java.lang.Object peek()
Description copied from interface: Channel
Return, but do not remove object at head of Channel, or null if it is empty.