BlockingFetchQueues (ImgLib2 Javadocs 0-SNAPSHOT API)

java.lang.Object
- net.imglib2.cache.queue.BlockingFetchQueues<E>

Type Parameters:

E - element type.
```
public class BlockingFetchQueues<E>
extends Object
```
TODO revise javadoc Queueing structure (intended for cache entries to be fetched). There is an array of ArrayDeques, ordered by priority. Elements are put(Object, int, boolean) with a priority and added to one of the queues, accordingly. take() returns an element from the highest priority non-empty queue. Furthermore, there is a prefetch deque of bounded size to provides elements when all the queues are exhausted. clearToPrefetch() empties all queues, and moves the removed elements to the prefetch queue.
Locking is adapted from ArrayBlockingQueue.
BlockingFetchQueues is constructed with the number of priority levels n. Priorities are consecutive integers 0 ... n-1, where 0 is the highest priority. Priorities of enqueued entries are clamped to the range 0 ... n-1.

Author:

Tobias Pietzsch

Constructor Summary

Constructors
Constructor and Description
`BlockingFetchQueues(int numPriorities, int numConsumers)`
`BlockingFetchQueues(int numPriorities, int numConsumers, int prefetchCapacity)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`clear()` Atomically removes all of the elements from this queue.
`void`	`clearToPrefetch()` Atomically removes all of the elements from this queue.
`long`	`getCurrentFrame()`
`int`	`getNumPriorities()`
`void`	`pause()` Pause the queue.
`void`	`put_unsafe(E element, int priority, boolean enqueuToFront)` Equivalent to `put(Object, int, boolean)`, but priorities are not clamped to the allowed range.
`void`	`put(E element, int priority, boolean enqueuToFront)` Add element to the queue of the specified priority.
`void`	`resume()`
`E`	`take()` Remove and return an element from the highest priority non-empty queue.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - BlockingFetchQueues
```
public BlockingFetchQueues(int numPriorities,
                           int numConsumers)
```
  - BlockingFetchQueues
```
public BlockingFetchQueues(int numPriorities,
                           int numConsumers,
                           int prefetchCapacity)
```
- Method Detail
  - put
```
public void put(E element,
                int priority,
                boolean enqueuToFront)
```
    Add element to the queue of the specified priority. The element can be added to the front or back of the queue.
    
    Parameters:
    
    element - the element to enqueue
    
    priority - lower values mean higher priority
    
    enqueuToFront - if true, enqueue element at the front (LIFO). if false, enqueue element at the back (FIFO)
  - put_unsafe
```
public void put_unsafe(E element,
                       int priority,
                       boolean enqueuToFront)
```
    Equivalent to put(Object, int, boolean), but priorities are not clamped to the allowed range. Will throw an ArrayIndexOutOfBoundsException if priority < 0 or priority >= numPriorities.
    Add element to the queue of the specified priority. The element can be added to the front or back of the queue.
    
    Parameters:
    
    element - the element to enqueue
    
    priority - lower values mean higher priority
    
    enqueuToFront - if true, enqueue element at the front (LIFO). if false, enqueue element at the back (FIFO)
  - take
```
public E take()
       throws InterruptedException
```
    Remove and return an element from the highest priority non-empty queue. If all queues are empty, then return an element from the prefetch deque. If the prefetch deque is also empty, then block.
    
    Returns:
    
    element.
    
    Throws:
    
    InterruptedException
  - pause
```
public void pause()
           throws InterruptedException
```
    Pause the queue. While the queue is paused, all consumer threads are held in take(). The pause() method itself blocks until all (of the pre-defined number of) consumer threads have arrived in take().
    While the queue is paused, all calls to take() block. (Calls to put() are not affected.)
    
    Throws:
    
    InterruptedException
  - resume
```
public void resume()
            throws InterruptedException
```
    Throws:
    
    InterruptedException
  - clearToPrefetch
```
public void clearToPrefetch()
```
    Atomically removes all of the elements from this queue. All queues will be empty after this call returns. Removed elements are moved to the prefetch deque.
  - clear
```
public void clear()
```
    Atomically removes all of the elements from this queue. All queues, as well as the prefetch deque, will be empty after this call returns.
  - getNumPriorities
```
public int getNumPriorities()
```
  - getCurrentFrame
```
public long getCurrentFrame()
```

Class BlockingFetchQueues<E>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

BlockingFetchQueues

BlockingFetchQueues

Method Detail

put

put_unsafe

take

pause

resume

clearToPrefetch

clear

getNumPriorities

getCurrentFrame