org.apache.mahout.math.map

Class OpenCharObjectHashMap<T>

java.lang.Object

org.apache.mahout.math.PersistentObject

org.apache.mahout.math.set.AbstractSet

org.apache.mahout.math.map.AbstractCharObjectMap<T>

org.apache.mahout.math.map.OpenCharObjectHashMap<T>

All Implemented Interfaces:

Serializable, Cloneable

public class OpenCharObjectHashMap<T>
extends AbstractCharObjectMap<T>

See Also:

Serialized Form

Field Summary

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
OpenCharObjectHashMap() Constructs an empty map with default capacity and default load factors.
OpenCharObjectHashMap(int initialCapacity) Constructs an empty map with the specified initial capacity and default load factors.
OpenCharObjectHashMap(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
void	clear() Removes all (key,value) associations from the receiver.
OpenCharObjectHashMap<T>	clone() Returns a deep copy of the receiver.
boolean	containsKey(char key) Returns true if the receiver contains the specified key.
boolean	containsValue(T value) Returns true if the receiver contains the specified value.
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(CharProcedure procedure) Applies a procedure to each key of the receiver, if any.
boolean	forEachPair(CharObjectProcedure<T> procedure) Applies a procedure to each (key,value) pair of the receiver, if any.
T	get(char key) Returns the value associated with the specified key.
protected void	getInternalFactors(int[] capacity, double[] minLoadFactor, double[] maxLoadFactor) Access for unit tests.
protected int	indexOfInsertion(char key)
protected int	indexOfKey(char key)
protected int	indexOfValue(T value)
void	keys(CharArrayList list) Fills all keys contained in the receiver into the specified list.
void	pairsMatching(CharObjectProcedure<T> condition, CharArrayList keyList, List<T> valueList) Fills all pairs satisfying a given condition into the specified lists.
boolean	put(char key, T value) Associates the given key with the given value.
protected void	rehash(int newCapacity) Rehashes the contents of the receiver into a new table with a smaller or larger capacity.
boolean	removeKey(char 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.
void	values(List<T> list) Fills all values contained in the receiver into the specified list.

Methods inherited from class org.apache.mahout.math.map.AbstractCharObjectMap

copy, equals, hashCode, keys, keysSortedByValue, pairsSortedByKey, pairsSortedByValue, toString, toStringByValue, values

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

Constructor Detail

OpenCharObjectHashMap

public OpenCharObjectHashMap()

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

OpenCharObjectHashMap

public OpenCharObjectHashMap(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.

OpenCharObjectHashMap

public OpenCharObjectHashMap(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 (key,value) associations from the receiver. Implicitly calls trimToSize().

Specified by:

clear in class AbstractSet

clone

public OpenCharObjectHashMap<T> clone()

Returns a deep copy of the receiver.

Overrides:

clone in class PersistentObject

Returns:

a deep copy of the receiver.

containsKey

public boolean containsKey(char key)

Returns true if the receiver contains the specified key.

Overrides:

containsKey in class AbstractCharObjectMap<T>

Returns:

true if the receiver contains the specified key.

containsValue

public boolean containsValue(T value)

Returns true if the receiver contains the specified value.

Overrides:

containsValue in class AbstractCharObjectMap<T>

Returns:

true if the receiver contains the specified value.

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 put()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(CharProcedure 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 AbstractCharObjectMap<T>

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.

forEachPair

public boolean forEachPair(CharObjectProcedure<T> procedure)

Applies a procedure to each (key,value) pair of the receiver, if any. Iteration order is guaranteed to be identical to the order used by method forEachKey(CharProcedure).

Overrides:

forEachPair in class AbstractCharObjectMap<T>

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.

get

public T get(char key)

Returns the value associated with the specified key. It is often a good idea to first check with containsKey(char) whether the given key has a value associated or not, i.e. whether there exists an association for the given key or not.

Specified by:

get in class AbstractCharObjectMap<T>

Parameters:

key - the key to be searched for.

Returns:

the value associated with the specified key; null if no such key is present.

indexOfInsertion

protected int indexOfInsertion(char 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(char 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.

indexOfValue

protected int indexOfValue(T value)

Parameters:

value - the value to be searched in the receiver.

Returns:

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

keys

public void keys(CharArrayList 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(CharProcedure).

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

Overrides:

keys in class AbstractCharObjectMap<T>

Parameters:

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

pairsMatching

public void pairsMatching(CharObjectProcedure<T> condition,
                 CharArrayList keyList,
                 List<T> valueList)

Fills all pairs satisfying a given condition into the specified lists. Fills into the lists, starting at index 0. After this call returns the specified lists both have a new size, the number of pairs satisfying the condition. Iteration order is guaranteed to be identical to the order used by method forEachKey(CharProcedure).

Example:

 CharObjectProcedure condition = new CharObjectProcedure() { // match even keys only
 public boolean apply(char key, Object value) { return key%2==0; }
 }
 keys = (8,7,6), values = (1,2,2) --> keyList = (6,8), valueList = (2,1)
 

Overrides:

pairsMatching in class AbstractCharObjectMap<T>

Parameters:

condition - the condition to be matched. Takes the current key as first and the current value as second argument.

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

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

put

public boolean put(char key,
          T value)

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

Specified by:

put in class AbstractCharObjectMap<T>

Parameters:

key - the key the value shall be associated with.

value - the value to be associated.

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.

removeKey

public boolean removeKey(char key)

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

Specified by:

removeKey in class AbstractCharObjectMap<T>

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

values

public void values(List<T> list)

Fills all values 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().

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

Overrides:

values in class AbstractCharObjectMap<T>

Parameters:

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

getInternalFactors

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

Access for unit tests.

Parameters:

capacity -

minLoadFactor -

maxLoadFactor -