ControllableQueue (Alluxio Core - Common Utilities 295 API)

java.lang.Object
- alluxio.util.executor.ControllableQueue<T>

Type Parameters:

T - the type of the value of ControllableQueue.DelayNode
```
public class ControllableQueue<T>
extends java.lang.Object
```
A controllable queue is a priority queue with ControllableQueue.DelayNodes. It supports tick the time forward and pop nodes whose delay is smaller than the past time.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static class`	`ControllableQueue.DelayNode<T>`	A delay node in delta queue which records the value and the total delay (which is the original delay plus the past time).

Constructor Summary

Constructors
Constructor Description

ControllableQueue()
Constructs a new ControllableQueue.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`add(long delay, T value)`	Adds a new node into the queue.
`long`	`getHeadDelay()`
`T`	`getHeadValue()`
`boolean`	`isEmpty()`
`T`	`pop()`
`boolean`	`remove(T element)`	Removes an element.
`void`	`tick(long duration)`	Jumps to a future time period.
`java.lang.String`	`toString()`

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

- Constructor Detail
  - ControllableQueue
```
public ControllableQueue()
```
    Constructs a new ControllableQueue.
- Method Detail
  - isEmpty
```
public boolean isEmpty()
```
    Returns:
    
    whether this queue is empty
  - getHeadValue
```
public T getHeadValue()
```
    Returns:
    
    the value of head element
  - getHeadDelay
```
public long getHeadDelay()
```
    Returns:
    
    the delay of head element
  - add
```
public void add(long delay,
                T value)
```
    Adds a new node into the queue.
    
    Parameters:
    
    delay - the delay in milliseconds
    
    value - the value
  - tick
```
public void tick(long duration)
```
    Jumps to a future time period.
    
    Parameters:
    
    duration - the time period to jump
  - pop
```
public T pop()
```
    Returns:
    
    the head element if it should be executed
  - remove
```
public boolean remove(T element)
```
    Removes an element.
    
    Parameters:
    
    element - an element
    
    Returns:
    
    true if the element removed successfully, false otherwise
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object