net.cscott.jutil
Class AbstractHeap<K,V>

java.lang.Object
  net.cscott.jutil.AbstractHeap<K,V>

All Implemented Interfaces:

Heap<K,V>

Direct Known Subclasses:

BinaryHeap, BinomialHeap, FibonacciHeap

public abstract class AbstractHeap<K,V>
extends Object
implements Heap<K,V>

AbstractHeap provides a skeletal implementation of the Heap interface, to minimize the effort required to implement this interface.

Version:

$Id: AbstractHeap.java,v 1.6 2006-10-30 20:14:40 cananian Exp $

Author:

C. Scott Ananian

Constructor Summary

protected

AbstractHeap(Comparator<K> c) Sole constructor, for invocation by subclass constructors.

Method Summary

abstract void	clear() Removes all entries from this Heap.
Comparator<K>	comparator() Returns the comparator used to compare keys in this Heap, or null if the keys' natural ordering is used.
abstract void	decreaseKey(Map.Entry<K,V> me, K newkey) Replace the key in the specified map entry with the specified smaller key.
abstract void	delete(Map.Entry<K,V> me) Remove the specified map entry from the mapping.
abstract Collection<Map.Entry<K,V>>	entries() Returns a collection view of all the Map.Entrys in this Heap.
protected Comparator<Map.Entry<K,V>>	entryComparator() Returns a comparator which can be used to compare Map.Entrys.
boolean	equals(Object o) Compares the specified object with this heap for equality.
Map.Entry<K,V>	extractMinimum() Remove and return a map entry with minimal key.
int	hashCode() Returns the hash code for this heap.
abstract Map.Entry<K,V>	insert(K key, V value) Inserts a node with the specified key and value into the Heap.
protected void	insert(Map.Entry<K,V> me) This method should insert the specified Map.Entry, which is not currently in the Heap, into the Heap.
boolean	isEmpty() Returns true if this Heap has no more entries.
protected Comparator<K>	keyComparator() Returns the comparator used to compare keys in this Heap.
abstract Map.Entry<K,V>	minimum() Returns a mapping entry with minimal key.
protected K	setKey(Map.Entry<K,V> me, K newkey) This method should set the key for the specified Map.Entry to the given newkey.
abstract int	size() Returns the number of entries in this Heap.
String	toString() Returns a string representation of this Heap.
void	union(Heap<? extends K,? extends V> h) Merges all of the mappings from the specified Heap into this Heap.
void	updateKey(Map.Entry<K,V> me, K newkey) Replace the key in the specified map entry with the specified key, which may be either larger or smaller than its current key.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

AbstractHeap

protected AbstractHeap(Comparator<K> c)

Sole constructor, for invocation by subclass constructors.

Method Detail

insert

public abstract Map.Entry<K,V> insert(K key,
                                      V value)

Description copied from interface: Heap

Inserts a node with the specified key and value into the Heap. Returns the generated Map.Entry which may be stored and eventually passed back to decreaseKey() or delete to remove this node.

Specified by:

insert in interface Heap<K,V>

minimum

public abstract Map.Entry<K,V> minimum()

Description copied from interface: Heap

Returns a mapping entry with minimal key.

Specified by:

minimum in interface Heap<K,V>

decreaseKey

public abstract void decreaseKey(Map.Entry<K,V> me,
                                 K newkey)

Description copied from interface: Heap

Replace the key in the specified map entry with the specified smaller key.

Specified by:

decreaseKey in interface Heap<K,V>

delete

public abstract void delete(Map.Entry<K,V> me)

Description copied from interface: Heap

Remove the specified map entry from the mapping.

Specified by:

delete in interface Heap<K,V>

size

public abstract int size()

Description copied from interface: Heap

Returns the number of entries in this Heap.

Specified by:

size in interface Heap<K,V>

entries

public abstract Collection<Map.Entry<K,V>> entries()

Description copied from interface: Heap

Returns a collection view of all the Map.Entrys in this Heap.

Specified by:

entries in interface Heap<K,V>

clear

public abstract void clear()

Description copied from interface: Heap

Removes all entries from this Heap.

Specified by:

clear in interface Heap<K,V>

updateKey

public void updateKey(Map.Entry<K,V> me,
                      K newkey)

Description copied from interface: Heap

Replace the key in the specified map entry with the specified key, which may be either larger or smaller than its current key.

Specified by:

updateKey in interface Heap<K,V>

insert

protected void insert(Map.Entry<K,V> me)

This method should insert the specified Map.Entry, which is not currently in the Heap, into the Heap. Implementation is optional, but it is required if you use the default implementation of updateKey().

setKey

protected K setKey(Map.Entry<K,V> me,
                   K newkey)

This method should set the key for the specified Map.Entry to the given newkey. Implementation is optional, but it is required if you use the default implementation of updateKey().

extractMinimum

public Map.Entry<K,V> extractMinimum()

Description copied from interface: Heap

Remove and return a map entry with minimal key.

Specified by:

extractMinimum in interface Heap<K,V>

union

public void union(Heap<? extends K,? extends V> h)

Description copied from interface: Heap

Merges all of the mappings from the specified Heap into this Heap. Note that duplicates are permitted. After calling union(), the Heap passed in as an argument will be empty.

Note that usually efficient implementations of this method require that the Heap argument be from the same implementation as this. (That is, they must both be binomial heaps, or both fibonacci heaps, etc.)

Specified by:

union in interface Heap<K,V>

isEmpty

public boolean isEmpty()

Description copied from interface: Heap

Returns true if this Heap has no more entries.

Specified by:

isEmpty in interface Heap<K,V>

hashCode

public int hashCode()

Description copied from interface: Heap

Returns the hash code for this heap. The hash code for this heap will be one greater than the hash code for the Collection returned by Heap.entries().

Specified by:

hashCode in interface Heap<K,V>

Overrides:

hashCode in class Object

equals

public boolean equals(Object o)

Description copied from interface: Heap

Compares the specified object with this heap for equality. Returns true iff the given object is also a Heap and the Collections returned by their Heap.entries() methods are equal using the equals() method of Collection.

Specified by:

equals in interface Heap<K,V>

Overrides:

equals in class Object

toString

public String toString()

Description copied from interface: Heap

Returns a string representation of this Heap.

Specified by:

toString in interface Heap<K,V>

Overrides:

toString in class Object

comparator

public Comparator<K> comparator()

Returns the comparator used to compare keys in this Heap, or null if the keys' natural ordering is used.

Specified by:

comparator in interface Heap<K,V>

keyComparator

protected Comparator<K> keyComparator()

Returns the comparator used to compare keys in this Heap. Will never return null.

entryComparator

protected Comparator<Map.Entry<K,V>> entryComparator()

Returns a comparator which can be used to compare Map.Entrys. Will never return null.