org.apache.mahout.math.set

Class OpenByteHashSet

java.lang.Object

org.apache.mahout.math.PersistentObject

org.apache.mahout.math.set.AbstractSet

org.apache.mahout.math.set.AbstractByteSet

org.apache.mahout.math.set.OpenByteHashSet

All Implemented Interfaces:

Serializable, Cloneable

public class OpenByteHashSet
extends AbstractByteSet

Open hash set of byte items;

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected static byte	FREE
protected static byte	FULL
protected static byte	NO_KEY_VALUE
protected static byte	REMOVED

Fields inherited from class org.apache.mahout.math.set.AbstractSet

DEFAULT_CAPACITY, DEFAULT_MAX_LOAD_FACTOR, DEFAULT_MIN_LOAD_FACTOR, distinct, highWaterMark, lowWaterMark, maxLoadFactor, minLoadFactor

Constructor Summary

Constructors

Constructor and Description
OpenByteHashSet() Constructs an empty map with default capacity and default load factors.
OpenByteHashSet(int initialCapacity) Constructs an empty map with the specified initial capacity and default load factors.
OpenByteHashSet(int initialCapacity, double minLoadFactor, double maxLoadFactor) Constructs an empty map with the specified initial capacity and the specified minimum and maximum load factor.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	add(byte key) Associates the given key with the given value.
void	clear() Removes all values associations from the receiver.
Object	clone() Returns a deep copy of the receiver.
boolean	contains(byte key) Returns true if the receiver contains the specified key.
void	ensureCapacity(int minCapacity) Ensures that the receiver can hold at least the specified number of associations without needing to allocate new internal memory.
boolean	forEachKey(ByteProcedure procedure) Applies a procedure to each key of the receiver, if any.
protected void	getInternalFactors(int[] capacity, double[] minLoadFactor, double[] maxLoadFactor) Access for unit tests.
protected int	indexOfInsertion(byte key)
protected int	indexOfKey(byte key)
void	keys(ByteArrayList list) Fills all keys contained in the receiver into the specified list.
protected void	rehash(int newCapacity) Rehashes the contents of the receiver into a new table with a smaller or larger capacity.
boolean	remove(byte key) Removes the given key with its associated element from the receiver, if present.
protected void	setUp(int initialCapacity, double minLoadFactor, double maxLoadFactor) Initializes the receiver.
void	trimToSize() Trims the capacity of the receiver to be the receiver's current size.

Methods inherited from class org.apache.mahout.math.set.AbstractByteSet

copy, equals, hashCode, keys, toString

Methods inherited from class org.apache.mahout.math.set.AbstractSet

chooseGrowCapacity, chooseHighWaterMark, chooseLowWaterMark, chooseMeanCapacity, chooseShrinkCapacity, equalsMindTheNull, isEmpty, nextPrime, size

Methods inherited from class java.lang.Object

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

Field Detail

FREE

protected static final byte FREE

See Also:

Constant Field Values

FULL

protected static final byte FULL

See Also:

Constant Field Values

REMOVED

protected static final byte REMOVED

See Also:

Constant Field Values

NO_KEY_VALUE

protected static final byte NO_KEY_VALUE

See Also:

Constant Field Values

Constructor Detail

OpenByteHashSet

public OpenByteHashSet()

Constructs an empty map with default capacity and default load factors.

OpenByteHashSet

public OpenByteHashSet(int initialCapacity)

Constructs an empty map with the specified initial capacity and default load factors.

Parameters:

initialCapacity - the initial capacity of the map.

Throws:

IllegalArgumentException - if the initial capacity is less than zero.

OpenByteHashSet

public OpenByteHashSet(int initialCapacity,
               double minLoadFactor,
               double maxLoadFactor)

Constructs an empty map with the specified initial capacity and the specified minimum and maximum load factor.

Parameters:

initialCapacity - the initial capacity.

minLoadFactor - the minimum load factor.

maxLoadFactor - the maximum load factor.

Throws:

IllegalArgumentException - if initialCapacity < 0 || (minLoadFactor < 0.0 || minLoadFactor >= 1.0) || (maxLoadFactor <= 0.0 || maxLoadFactor >= 1.0) || (minLoadFactor >= maxLoadFactor).

Method Detail

clear

public void clear()

Removes all values associations from the receiver. Implicitly calls trimToSize().

Specified by:

clear in class AbstractSet

clone

public Object clone()

Returns a deep copy of the receiver.

Overrides:

clone in class PersistentObject

Returns:

a deep copy of the receiver.

contains

public boolean contains(byte key)

Returns true if the receiver contains the specified key.

Overrides:

contains in class AbstractByteSet

Returns:

true if the receiver contains the specified key.

ensureCapacity

public void ensureCapacity(int minCapacity)

Ensures that the receiver can hold at least the specified number of associations without needing to allocate new internal memory. If necessary, allocates new internal memory and increases the capacity of the receiver.

This method never need be called; it is for performance tuning only. Calling this method before add()ing a large number of associations boosts performance, because the receiver will grow only once instead of potentially many times and hash collisions get less probable.

Overrides:

ensureCapacity in class AbstractSet

Parameters:

minCapacity - the desired minimum capacity.

forEachKey

public boolean forEachKey(ByteProcedure procedure)

Applies a procedure to each key of the receiver, if any. Note: Iterates over the keys in no particular order. Subclasses can define a particular order, for example, "sorted by key". All methods which can be expressed in terms of this method (most methods can) must guarantee to use the same order defined by this method, even if it is no particular order. This is necessary so that, for example, methods keys and values will yield association pairs, not two uncorrelated lists.

Specified by:

forEachKey in class AbstractByteSet

Parameters:

procedure - the procedure to be applied. Stops iteration if the procedure returns false, otherwise continues.

Returns:

false if the procedure stopped before all keys where iterated over, true otherwise.

indexOfInsertion

protected int indexOfInsertion(byte key)

Parameters:

key - the key to be added to the receiver.

Returns:

the index where the key would need to be inserted, if it is not already contained. Returns -index-1 if the key is already contained at slot index. Therefore, if the returned index < 0, then it is already contained at slot -index-1. If the returned index >= 0, then it is NOT already contained and should be inserted at slot index.

indexOfKey

protected int indexOfKey(byte key)

Parameters:

key - the key to be searched in the receiver.

Returns:

the index where the key is contained in the receiver, returns -1 if the key was not found.

keys

public void keys(ByteArrayList list)

Fills all keys contained in the receiver into the specified list. Fills the list, starting at index 0. After this call returns the specified list has a new size that equals this.size(). Iteration order is guaranteed to be identical to the order used by method forEachKey(ByteProcedure).

This method can be used to iterate over the keys of the receiver.

Overrides:

keys in class AbstractByteSet

Parameters:

list - the list to be filled, can have any size.

add

public boolean add(byte key)

Associates the given key with the given value. Replaces any old (key,someOtherValue) association, if existing.

Specified by:

add in class AbstractByteSet

Parameters:

key - the key the value shall be associated with.

Returns:

true if the receiver did not already contain such a key; false if the receiver did already contain such a key - the new value has now replaced the formerly associated value.

rehash

protected void rehash(int newCapacity)

Rehashes the contents of the receiver into a new table with a smaller or larger capacity. This method is called automatically when the number of keys in the receiver exceeds the high water mark or falls below the low water mark.

remove

public boolean remove(byte key)

Removes the given key with its associated element from the receiver, if present.

Specified by:

remove in class AbstractByteSet

Parameters:

key - the key to be removed from the receiver.

Returns:

true if the receiver contained the specified key, false otherwise.

setUp

protected final void setUp(int initialCapacity,
         double minLoadFactor,
         double maxLoadFactor)

Initializes the receiver.

Overrides:

setUp in class AbstractSet

Parameters:

initialCapacity - the initial capacity of the receiver.

minLoadFactor - the minLoadFactor of the receiver.

maxLoadFactor - the maxLoadFactor of the receiver.

Throws:

IllegalArgumentException - if initialCapacity < 0 || (minLoadFactor < 0.0 || minLoadFactor >= 1.0) || (maxLoadFactor <= 0.0 || maxLoadFactor >= 1.0) || (minLoadFactor >= maxLoadFactor).

trimToSize

public void trimToSize()

Trims the capacity of the receiver to be the receiver's current size. Releases any superfluous internal memory. An application can use this operation to minimize the storage of the receiver.

Overrides:

trimToSize in class AbstractSet

getInternalFactors

protected void getInternalFactors(int[] capacity,
                      double[] minLoadFactor,
                      double[] maxLoadFactor)

Access for unit tests.

Parameters:

capacity -

minLoadFactor -

maxLoadFactor -