Package it.unimi.di.law.warc.util

Class ReorderingBlockingQueue<E>

java.lang.Object

it.unimi.di.law.warc.util.ReorderingBlockingQueue<E>

public class ReorderingBlockingQueue<E>
extends java.lang.Object

A blocking queue holding a fixed amount of timestamped items. The put(Object, long) must be called with an object and a timestamp. Timestamps must be a contiguous interval of the natural numbers starting at zero, and objects will be returned in timestamp order. Failure to comply with the contract (i.e., missing timestamps) will cause the queue to block forever.

put(Object, long) might block if there is not enough space to keep track of the object (i.e., if its timestamp is too far in time w.r.t. the timestamp that would be returned next by the queue). take() might block if the object with the next timestamp has not been put(Object, long) yet.

All methods of this class complete in constant time.

Constructor Summary

Constructors

Constructor	Description
ReorderingBlockingQueue(int capacity)	Creates a ReorderingBlockingQueue with the given fixed capacity.

Method Summary

Modifier and Type	Method	Description
boolean	isEmpty()	Returns whether this queue is empty.
void	put(E e, long timeStamp)	Inserts an element with given timestamp, waiting for space to become available if the timestamp of the element minus the current timestamp of the queue exceeds the queue capacity.
int	size()	Returns the number of elements in this queue.
E	take()	Returns the element with the next timestamp, waiting until it is available.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReorderingBlockingQueue

public ReorderingBlockingQueue(int capacity)

Creates a ReorderingBlockingQueue with the given fixed capacity.

Parameters:

capacity - the capacity of this queue (will be rounded to the next power of two).

Method Detail

put

public void put(E e,
                long timeStamp)
         throws java.lang.InterruptedException

Inserts an element with given timestamp, waiting for space to become available if the timestamp of the element minus the current timestamp of the queue exceeds the queue capacity.

Parameters:

e - an element.

timeStamp - the timestamp of e.

Throws:

java.lang.InterruptedException

take

public E take()
       throws java.lang.InterruptedException

Returns the element with the next timestamp, waiting until it is available.

Note that because of the reordering semantics, an invocation of this method on a nonempty queue might block nonetheless.

Returns:

the element with the next timestamp.

Throws:

java.lang.InterruptedException

size

public int size()

Returns the number of elements in this queue.

Returns:

the number of elements in this queue

See Also:

isEmpty()

isEmpty

public boolean isEmpty()

Returns whether this queue is empty.

Returns:

whether this queue is empty.