com.sosnoski.util.hashset
Class StringHashSet

java.lang.Object
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  +--com.sosnoski.util.ObjectHashBase
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        +--com.sosnoski.util.hashset.ObjectSetBase
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              +--com.sosnoski.util.hashset.StringHashSet

public class StringHashSet

extends ObjectSetBase

Hash set of Strings. 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 implementation.

Version:

1.1

Author:

Dennis M. Sosnoski

Field Summary

protected boolean	m_identCompare Use identity comparison flag.
protected boolean	m_identHash Use identity hash flag.
protected java.lang.String[]	m_keyTable Array of value table slots.

Fields inherited from class com.sosnoski.util.ObjectHashBase

DEFAULT_FILL, IDENTITY_COMP, IDENTITY_HASH, m_arraySize, m_entryCount, m_entryLimit, m_fillFraction, m_hitOffset, MINIMUM_SIZE, STANDARD_HASH

Constructor Summary

StringHashSet()
Default constructor.

StringHashSet(int count)
Constructor with only size supplied.

StringHashSet(int count, double fill)
Constructor with size and fill fraction supplied.

StringHashSet(int count, double fill, java.lang.Object tech)
Constructor with full specification.

StringHashSet(int count, java.lang.Object tech)
Constructor with size and technique supplied.

StringHashSet(java.lang.Object tech)
Constructor with only technique supplied.

StringHashSet(StringHashSet base)
Copy (clone) constructor.

Method Summary

boolean	add(java.lang.String key) Add a key to the set.
protected int	assignSlot(java.lang.String key) Assign slot for entry.
java.lang.Object	clone() Construct a copy of the set.
boolean	contains(java.lang.String key) Check if key is in set.
protected java.lang.Object[]	getKeyArray() Get the backing array of keys.
protected boolean	reinsert(int slot) Reinsert a key into the hash set.
boolean	remove(java.lang.String key) Remove an entry from the set.
protected void	restructure(java.lang.Object karray) Restructure the set.
protected void	setKeyArray(java.lang.Object array) Set the backing array of keys.

Methods inherited from class com.sosnoski.util.hashset.ObjectSetBase

internalRemove, iterator, reallocate

Methods inherited from class com.sosnoski.util.ObjectHashBase

clear, ensureCapacity, freeSlot, growCapacity, size, standardFind, standardSlot, stepSlot

Methods inherited from class java.lang.Object

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

Field Detail

m_keyTable

protected java.lang.String[] m_keyTable

Array of value table slots.

m_identHash

protected boolean m_identHash

Use identity hash flag.

m_identCompare

protected boolean m_identCompare

Use identity comparison flag.

Constructor Detail

StringHashSet

public StringHashSet(int count,
                     double fill,
                     java.lang.Object tech)

Constructor with full specification.

Parameters:

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

fill - fraction full allowed for set before growing

tech - hash technique specifier (one of STANDARD_HASH, IDENTITY_COMP, or IDENTITY_HASH, inherited from ObjectHashBase)

StringHashSet

public StringHashSet(int count,
                     double fill)

Constructor with size and fill fraction supplied. Uses default value for hash technique.

Parameters:

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

fill - fraction full allowed for set before growing

StringHashSet

public StringHashSet(int count,
                     java.lang.Object tech)

Constructor with size and technique supplied. Uses default value for fill fraction.

Parameters:

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

tech - hash technique specifier (one of STANDARD_HASH, IDENTITY_COMP, or IDENTITY_HASH, inherited from ObjectHashBase)

StringHashSet

public StringHashSet(int count)

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

Parameters:

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

StringHashSet

public StringHashSet(java.lang.Object tech)

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

Parameters:

tech - hash technique specifier (one of STANDARD_HASH, IDENTITY_COMP, or IDENTITY_HASH, inherited from ObjectHashBase)

StringHashSet

public StringHashSet()

Default constructor.

StringHashSet

public StringHashSet(StringHashSet base)

Copy (clone) constructor.

Parameters:

base - instance being copied

Method Detail

getKeyArray

protected 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 ObjectHashBase

Returns:

backing key array object

setKeyArray

protected 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 ObjectHashBase

Parameters:

array - backing key array object

reinsert

protected boolean reinsert(int slot)

Reinsert a key into the hash set. This implementation of an abstract method is used when the set is being directly modified by the base class, and does not adjust the count present or check the set capacity.

Overrides:

reinsert in class ObjectSetBase

Parameters:

slot - position of key to be reinserted into hash set

Returns:

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

restructure

protected void restructure(java.lang.Object karray)

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

Overrides:

restructure in class ObjectSetBase

Parameters:

karray - array of keys

assignSlot

protected int assignSlot(java.lang.String key)

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 set

Returns:

slot at which key was added

add

public boolean add(java.lang.String key)

Add a key to the set.

Parameters:

key - key to be added to set

Returns:

true if key added to set, false if already present in set

contains

public boolean contains(java.lang.String key)

Check if key is in set.

Parameters:

key - key to be found in set

Returns:

true if key found in set, false if not

remove

public boolean remove(java.lang.String key)

Remove an entry from the set.

Parameters:

key - key to be removed from set

Returns:

true if key successfully removed from set, false if key not found in set

clone

public java.lang.Object clone()

Construct a copy of the set.

Overrides:

clone in class java.lang.Object

Returns:

shallow copy of set