org.jibx.runtime.impl

Class StringIntHashMap

java.lang.Object

org.jibx.runtime.impl.StringIntHashMap

public class StringIntHashMap
extends Object

Hash map using String values as keys mapped to primitive int 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. The map implementation is not very efficient when resizing, but works well when the size of the map is known in advance.

Version:

1.1

Author:

Dennis M. Sosnoski

Field Summary

Fields

Modifier and Type	Field and Description
protected static double	DEFAULT_FILL Default fill fraction allowed before growing table.
static int	DEFAULT_NOT_FOUND Default value returned when key not found in table.
protected int	m_arraySize Size of array used for keys.
protected int	m_entryCount Number of entries present in table.
protected int	m_entryLimit Entries allowed before growing table.
protected double	m_fillFraction Fill fraction allowed for this hash table.
protected int	m_hitOffset Offset added (modulo table size) to slot number on collision.
protected String[]	m_keyTable Array of key table slots.
protected int	m_notFoundValue Value returned when key not found in table.
protected int[]	m_valueTable Array of value table slots.
protected static int	MINIMUM_SIZE Minimum size used for hash table.

Constructor Summary

Constructors

Constructor and Description
StringIntHashMap() Default constructor.
StringIntHashMap(int count) Constructor with only size supplied.
StringIntHashMap(int count, double fill) Constructor with size and fill fraction specified.
StringIntHashMap(int count, double fill, int miss) Constructor with full specification.
StringIntHashMap(StringIntHashMap base) Copy (clone) constructor.

Method Summary

Methods

Modifier and Type	Method and Description
int	add(String key, int value) Add an entry to the table.
Object	clone() Construct a copy of the table.
boolean	containsKey(String key) Check if an entry is present in the table.
int	get(String key) Find an entry in the table.
protected void	internalRemove(int slot) Internal remove pair from the table.
int	remove(String key) Remove an entry from the table.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_NOT_FOUND

public static final int DEFAULT_NOT_FOUND

Default value returned when key not found in table.

See Also:

Constant Field Values

DEFAULT_FILL

protected static final double DEFAULT_FILL

Default fill fraction allowed before growing table.

See Also:

Constant Field Values

MINIMUM_SIZE

protected static final int MINIMUM_SIZE

Minimum size used for hash table.

See Also:

Constant Field Values

m_fillFraction

protected final double m_fillFraction

Fill fraction allowed for this hash table.

m_entryCount

protected int m_entryCount

Number of entries present in table.

m_entryLimit

protected int m_entryLimit

Entries allowed before growing table.

m_arraySize

protected int m_arraySize

Size of array used for keys.

m_hitOffset

protected int m_hitOffset

Offset added (modulo table size) to slot number on collision.

m_keyTable

protected String[] m_keyTable

Array of key table slots.

m_valueTable

protected int[] m_valueTable

Array of value table slots.

m_notFoundValue

protected int m_notFoundValue

Value returned when key not found in table.

Constructor Detail

StringIntHashMap

public StringIntHashMap(int count,
                double fill,
                int miss)

Constructor with full specification.

Parameters:

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

fill - fraction full allowed for table before growing

miss - value returned when key not found in table

StringIntHashMap

public StringIntHashMap(int count,
                double fill)

Constructor with size and fill fraction specified. Uses default hash technique and value returned when key not found in table.

Parameters:

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

fill - fraction full allowed for table before growing

StringIntHashMap

public StringIntHashMap(int count)

Constructor with only size supplied. Uses default hash technique and values for fill fraction and value returned when key not found in table.

Parameters:

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

StringIntHashMap

public StringIntHashMap()

Default constructor.

StringIntHashMap

public StringIntHashMap(StringIntHashMap base)

Copy (clone) constructor.

Parameters:

base - instance being copied

Method Detail

internalRemove

protected void internalRemove(int slot)

Internal remove pair from the table. Removes the pair from the table by setting the key entry to null and adjusting the count present, then chains through the table to reinsert any other pairs which may have collided with the removed pair. If the associated value is an object reference, it should be set to null before this method is called.

Parameters:

slot - index number of pair to be removed

add

public int add(String key,
      int 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 (non- null)

value - associated value for key

Returns:

value previously associated with key, or reserved not found value if key not previously present in table

containsKey

public final boolean containsKey(String key)

Check if an entry is present in the table. This method is supplied to support the use of values matching the reserved not found value.

Parameters:

key - key for entry to be found

Returns:

true if key found in table, false if not

get

public final int get(String key)

Find an entry in the table.

Parameters:

key - key for entry to be returned

Returns:

value for key, or reserved not found value if key not found

remove

public int remove(String key)

Remove an entry from the table. If multiple entries are present with the same key value, only the first one found will be removed.

Parameters:

key - key to be removed from table

Returns:

value associated with removed key, or reserved not found value if key not found in table

clone

public Object clone()

Construct a copy of the table.

Overrides:

clone in class Object

Returns:

shallow copy of table