thread
Class Deque

java.lang.Object
  thread.Deque

All Implemented Interfaces:

java.io.Serializable

public class Deque
extends java.lang.Object
implements java.io.Serializable

This Deque class implements a double ended queue in a similar way as the class BoundedBuffer does. It has some capacity to store objects. With the method put objects are placed into the buffer. With the get method objects are taken from the buffer in FIFO order and with pop objects are taken from the buffer in LIFO order. put blocks if there is no space to place a object into the buffer. get and pop block if there are no objects in the channel. This class is safe against Thread InterruptedException.

Author:

Akitoshi Yoshida, Heinz Kredel.

See Also:

see Channel see Queue see Deque see MemoryChannel see SyncChannel see Stack, Serialized Form

Field Summary

private java.lang.Object[]	buffer the buffer is the deque contents.
private Semaphore	empty a semaphore indicating an empty cell.
private int	front index to the first filled cell.
private Semaphore	full a semaphore indicating a filled cell.
private java.lang.Object	rcv mutex for receive.
private int	rear index to the first empty cell.
private int	size the buffer's size.
private java.lang.Object	snd mutex for send.
static java.lang.String	undefined Declares an undefined value of type String.

Constructor Summary

Deque(int init)
Construct a Deque.

Method Summary

boolean	empty() Tests if the deque is empty.
java.lang.Object	get() Get an object from the deque, FIFO order.
java.lang.Object	get(int m) Get an object from the deque within given timeout, FIFO order.
java.lang.Object	pop() Pop an object from the deque, LIFO order.
java.lang.Object	pop(int m) Pop an object from the deque within given timeout, LIFO order.
void	push(java.lang.Object v) Push an object to the deque.
void	put(java.lang.Object v) Put an object to the deque.
int	size() Get the number of elements in the deque.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

buffer

private java.lang.Object[] buffer

the buffer is the deque contents.

size

private int size

the buffer's size.

front

private int front

index to the first filled cell.

rear

private int rear

index to the first empty cell.

empty

private Semaphore empty

a semaphore indicating an empty cell.

full

private Semaphore full

a semaphore indicating a filled cell.

snd

private java.lang.Object snd

mutex for send.

rcv

private java.lang.Object rcv

mutex for receive.

undefined

public static final java.lang.String undefined

Declares an undefined value of type String.

See Also:

Constant Field Values

Constructor Detail

Deque

public Deque(int init)

Construct a Deque.

Parameters:

init - An integer which defines the deques size.

Method Detail

put

public void put(java.lang.Object v)
         throws java.lang.InterruptedException

Put an object to the deque. Return without object put if Interrupted.

Throws:

InterruptedException.

java.lang.InterruptedException

push

public void push(java.lang.Object v)
          throws java.lang.InterruptedException

Push an object to the deque. Return without object pushed if Interrupted.

Throws:

InterruptedException.

java.lang.InterruptedException

get

public java.lang.Object get()
                     throws java.lang.InterruptedException

Get an object from the deque, FIFO order.

Returns:

null object if Interrupted.

Throws:

InterruptedException.

java.lang.InterruptedException

get

public java.lang.Object get(int m)
                     throws java.lang.InterruptedException

Get an object from the deque within given timeout, FIFO order.

Returns:

null object if Interrupted.

Throws:

InterruptedException.

java.lang.InterruptedException

pop

public java.lang.Object pop()
                     throws java.lang.InterruptedException

Pop an object from the deque, LIFO order.

Returns:

null object if Interrupted.

Throws:

InterruptedException.

java.lang.InterruptedException

pop

public java.lang.Object pop(int m)
                     throws java.lang.InterruptedException

Pop an object from the deque within given timeout, LIFO order.

Returns:

null object if Interrupted.

Throws:

InterruptedException.

java.lang.InterruptedException

empty

public boolean empty()

Tests if the deque is empty.

size

public int size()

Get the number of elements in the deque.

Returns:

size of deque.