com.sosnoski.util.hashmap
Class IntStringHashMap

java.lang.Object
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  +--com.sosnoski.util.PrimitiveHashBase
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        +--com.sosnoski.util.hashmap.PrimitiveKeyBase
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              +--com.sosnoski.util.hashmap.IntStringHashMap

public class IntStringHashMap

extends PrimitiveKeyBase

Hash map using primitive int values as keys mapped to String values. This implementation is unsynchronized in order to provide the best possible performance for typical usage scenarios, so explicit synchronization must be implemented by a wrapper class or directly by the application in cases where instances are modified in a multithreaded environment. See the base classes for other details of the hash map implementation.

Version:

1.1

Author:

Dennis M. Sosnoski

Field Summary

protected int[]	m_keyTable Array of key table slots.
protected java.lang.String[]	m_valueTable Array of value table slots.

Fields inherited from class com.sosnoski.util.PrimitiveHashBase

DEFAULT_FILL, KEY_MULTIPLIER, m_entryCount, m_entryLimit, m_fillFraction, m_flagTable, m_hitOffset, MINIMUM_SIZE

Constructor Summary

IntStringHashMap()
Default constructor.

IntStringHashMap(int count)
Constructor with only size supplied.

IntStringHashMap(int count, double fill)
Constructor with full specification.

IntStringHashMap(IntStringHashMap base)
Copy (clone) constructor.

Method Summary

java.lang.String	add(int key, java.lang.String value) Add an entry to the table.
protected int	assignSlot(int key, java.lang.String value) Assign slot for entry.
java.lang.Object	clone() Construct a copy of the table.
protected int	computeSlot(int key) Compute the base slot for a key.
boolean	containsKey(int key) Check if an entry is present in the table.
java.lang.String	get(int key) Find an entry in the table.
protected java.lang.Object	getKeyArray() Get the backing array of keys.
protected java.lang.Object	getValueArray() Get the backing array of values.
protected int	internalFind(int key) Internal find key in table.
protected boolean	reinsert(int slot) Reinsert an entry into the hash map.
java.lang.String	remove(int key) Remove an entry from the table.
protected void	restructure(boolean[] flags, java.lang.Object karray, java.lang.Object varray) Restructure the table.
protected void	setKeyArray(java.lang.Object array) Set the backing array of keys.
protected void	setValueArray(java.lang.Object array) Set the backing array of values.
java.util.Iterator	valueIterator() Return an iterator for the value Objects in this map.

Methods inherited from class com.sosnoski.util.hashmap.PrimitiveKeyBase

clear, reallocate

Methods inherited from class com.sosnoski.util.PrimitiveHashBase

ensureCapacity, freeSlot, growCapacity, size, stepSlot

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

m_keyTable

protected int[] m_keyTable

Array of key table slots.

m_valueTable

protected java.lang.String[] m_valueTable

Array of value table slots.

Constructor Detail

IntStringHashMap

public IntStringHashMap(int count,
                        double fill)

Constructor with full specification.

Parameters:

count - number of values to assume in initial sizing of table

fill - fraction full allowed for table before growing

IntStringHashMap

public IntStringHashMap(int count)

Constructor with only size supplied. Uses default value for fill fraction.

Parameters:

count - number of values to assume in initial sizing of table

IntStringHashMap

public IntStringHashMap()

Default constructor.

IntStringHashMap

public IntStringHashMap(IntStringHashMap base)

Copy (clone) constructor.

Parameters:

base - instance being copied

Method Detail

getKeyArray

protected final java.lang.Object getKeyArray()

Get the backing array of keys. This implementation of an abstract method is used by the type-agnostic base class code to access the array used for type-specific storage by the child class.

Overrides:

getKeyArray in class PrimitiveHashBase

Returns:

backing key array object

setKeyArray

protected final void setKeyArray(java.lang.Object array)

Set the backing array of keys. This implementation of an abstract method is used by the type-agnostic base class code to set the array used for type-specific storage by the child class.

Overrides:

setKeyArray in class PrimitiveHashBase

Parameters:

array - backing key array object

getValueArray

protected final java.lang.Object getValueArray()

Get the backing array of values. This implementation of an abstract method is used by the type-agnostic base class code to access the array used for type-specific storage by the child class.

Overrides:

getValueArray in class PrimitiveKeyBase

Returns:

backing key array object

setValueArray

protected final void setValueArray(java.lang.Object array)

Set the backing array of values. This implementation of an abstract method is used by the type-agnostic base class code to set the array used for type-specific storage by the child class.

Overrides:

setValueArray in class PrimitiveKeyBase

Parameters:

array - backing value array object

reinsert

protected final boolean reinsert(int slot)

Reinsert an entry into the hash map. This method is designed for internal use when the table is being modified, and does not adjust the count present or check the table capacity.

Parameters:

slot - position of entry to be reinserted into hash map

Returns:

true if the slot number used by the entry has has changed, false if not

restructure

protected void restructure(boolean[] flags,
                           java.lang.Object karray,
                           java.lang.Object varray)

Restructure the table. This implementation of an abstract method is used when the table is increasing or decreasing in size, and works directly with the old table representation arrays. It inserts pairs from the old arrays directly into the table without adjusting the count present or checking the table size.

Overrides:

restructure in class PrimitiveKeyBase

Parameters:

flags - array of flags for array slots used

karray - array of keys

varray - array of values

computeSlot

protected final int computeSlot(int key)

Compute the base slot for a key.

Parameters:

key - key value to be computed

Returns:

base slot for key

assignSlot

protected int assignSlot(int key,
                         java.lang.String value)

Assign slot for entry. Starts at the slot found by the hashed key value. If this slot is already occupied, it steps the slot number and checks the resulting slot, repeating until an unused slot is found. This method does not check for duplicate keys, so it should only be used for internal reordering of the tables.

Parameters:

key - key to be added to table

value - associated value for key

Returns:

slot at which entry was added

add

public java.lang.String add(int key,
                            java.lang.String value)

Add an entry to the table. If the key is already present in the table, this replaces the existing value associated with the key.

Parameters:

key - key to be added to table

value - associated value for key

Returns:

value previously associated with key, null if key not previously present in table

internalFind

protected final int internalFind(int key)

Internal find key in table.

Parameters:

key - to be found in table

Returns:

index of matching key, or -index-1 of slot to be used for inserting key in table if not already present (always negative)

containsKey

public final boolean containsKey(int key)

Check if an entry is present in the table. This method is supplied to support the use of null values in the table.

Parameters:

key - key for entry to be found

Returns:

true if key found in table, false if not

get

public final java.lang.String get(int key)

Find an entry in the table.

Parameters:

key - key for entry to be returned

Returns:

value for key, or null if key not found

remove

public java.lang.String remove(int key)

Remove an entry from the table.

Parameters:

key - key to be removed from table

Returns:

value associated with removed key, null if key not found in table

valueIterator

public final java.util.Iterator valueIterator()

Return an iterator for the value Objects in this map. The iterator returns all values in arbitrary order, but is not "live". Any changes to the map while the iteration is in progress will give indeterminant results.

Returns:

iterator for values in array

clone

public java.lang.Object clone()

Construct a copy of the table.

Overrides:

clone in class java.lang.Object

Returns:

shallow copy of table