PriorityQueue

java.lang.Object
- org.datavec.api.berkeley.PriorityQueue<E>

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.util.Iterator<E>, PriorityQueueInterface<E>
```
public class PriorityQueue<E>
extends java.lang.Object
implements java.util.Iterator<E>, java.io.Serializable, java.lang.Cloneable, PriorityQueueInterface<E>
```
A priority queue based on a binary heap. Note that this implementation does not efficiently support containment, removal, or element promotion (decreaseKey) -- these methods are therefore not yet implemented. It is a maximum priority queue, so next() gives the highest-priority object.

See Also:

Serialized Form

Constructor Summary

Constructors
Constructor and Description

PriorityQueue()

PriorityQueue(int capacity)

Constructors
Constructor and Description
`PriorityQueue()`
`PriorityQueue(int capacity)`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`add(E key, double priority)`
`Counter<E>`	`asCounter()` Returns a counter whose keys are the elements in this priority queue, and whose counts are the priorities in this queue.
`PriorityQueue<E>`	`clone()` Returns a clone of this priority queue.
`double`	`getPriority()` Gets the priority of the highest-priority element of the queue.
`protected void`	`grow(int newCapacity)`
`boolean`	`hasNext()` Returns true if the priority queue is non-empty
`protected void`	`heapifyDown(int loc)`
`protected void`	`heapifyUp(int loc)`
`boolean`	`isEmpty()` True if the queue is empty (size == 0).
`protected int`	`leftChild(int loc)`
`static void`	`main(java.lang.String[] args)`
`E`	`next()` Returns the element in the queue with highest priority, and pops it from the queue.
`protected int`	`parent(int loc)`
`E`	`peek()` Returns the highest-priority element in the queue, but does not pop it.
`void`	`put(E key, double priority)` Adds a key to the queue with the given priority.
`void`	`remove()` Not supported -- next() already removes the head of the queue.
`protected void`	`removeFirst()`
`protected int`	`rightChild(int loc)`
`int`	`size()` Number of elements in the queue.
`protected void`	`swap(int loc1, int loc2)`
`java.lang.String`	`toString()` Returns a representation of the queue in decreasing priority order.
`java.lang.String`	`toString(int maxKeysToPrint, boolean multiline)` Returns a representation of the queue in decreasing priority order, displaying at most maxKeysToPrint elements and optionally printing one element per line.

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

Methods inherited from interface java.util.Iterator
forEachRemaining

- Constructor Detail
  - PriorityQueue
```
public PriorityQueue()
```
  - PriorityQueue
```
public PriorityQueue(int capacity)
```
- Method Detail
  - grow
```
protected void grow(int newCapacity)
```
  - parent
```
protected int parent(int loc)
```
  - leftChild
```
protected int leftChild(int loc)
```
  - rightChild
```
protected int rightChild(int loc)
```
  - heapifyUp
```
protected void heapifyUp(int loc)
```
  - heapifyDown
```
protected void heapifyDown(int loc)
```
  - swap
```
protected void swap(int loc1,
                    int loc2)
```
  - removeFirst
```
protected void removeFirst()
```
  - hasNext
```
public boolean hasNext()
```
    Description copied from interface: PriorityQueueInterface
    
    Returns true if the priority queue is non-empty
    
    Specified by:
    
    hasNext in interface java.util.Iterator<E>
    
    Specified by:
    
    hasNext in interface PriorityQueueInterface<E>
  - next
```
public E next()
```
    Description copied from interface: PriorityQueueInterface
    
    Returns the element in the queue with highest priority, and pops it from the queue.
    
    Specified by:
    
    next in interface java.util.Iterator<E>
    
    Specified by:
    
    next in interface PriorityQueueInterface<E>
  - remove
```
public void remove()
```
    Description copied from interface: PriorityQueueInterface
    
    Not supported -- next() already removes the head of the queue.
    
    Specified by:
    
    remove in interface java.util.Iterator<E>
    
    Specified by:
    
    remove in interface PriorityQueueInterface<E>
  - peek
```
public E peek()
```
    Description copied from interface: PriorityQueueInterface
    
    Returns the highest-priority element in the queue, but does not pop it.
    
    Specified by:
    
    peek in interface PriorityQueueInterface<E>
  - getPriority
```
public double getPriority()
```
    Description copied from interface: PriorityQueueInterface
    
    Gets the priority of the highest-priority element of the queue.
    
    Specified by:
    
    getPriority in interface PriorityQueueInterface<E>
  - size
```
public int size()
```
    Description copied from interface: PriorityQueueInterface
    
    Number of elements in the queue.
    
    Specified by:
    
    size in interface PriorityQueueInterface<E>
  - isEmpty
```
public boolean isEmpty()
```
    Description copied from interface: PriorityQueueInterface
    
    True if the queue is empty (size == 0).
    
    Specified by:
    
    isEmpty in interface PriorityQueueInterface<E>
  - add
```
public boolean add(E key,
                   double priority)
```
  - put
```
public void put(E key,
                double priority)
```
    Description copied from interface: PriorityQueueInterface
    
    Adds a key to the queue with the given priority. If the key is already in the queue, it will be added an additional time, NOT promoted/demoted.
    
    Specified by:
    
    put in interface PriorityQueueInterface<E>
  - toString
```
public java.lang.String toString()
```
    Returns a representation of the queue in decreasing priority order.
    
    Overrides:
    
    toString in class java.lang.Object
  - toString
```
public java.lang.String toString(int maxKeysToPrint,
                                 boolean multiline)
```
    Returns a representation of the queue in decreasing priority order, displaying at most maxKeysToPrint elements and optionally printing one element per line.
    
    Parameters:
    
    maxKeysToPrint -
    
    multiline - TODO
  - asCounter
```
public Counter<E> asCounter()
```
    Returns a counter whose keys are the elements in this priority queue, and whose counts are the priorities in this queue. In the event there are multiple instances of the same element in the queue, the counter's count will be the sum of the instances' priorities.
    
    Returns:
  - clone
```
public PriorityQueue<E> clone()
```
    Returns a clone of this priority queue. Modifications to one will not affect modifications to the other.
    
    Overrides:
    
    clone in class java.lang.Object
  - main
```
public static void main(java.lang.String[] args)
```

Class PriorityQueue<E>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Iterator

Constructor Detail

PriorityQueue

PriorityQueue

Method Detail

grow

parent

leftChild

rightChild

heapifyUp

heapifyDown

swap

removeFirst

hasNext

next

remove

peek

getPriority

size

isEmpty

add

put

toString

toString

asCounter

clone

main