gnu.trove.impl.hash
Class TObjectHash<T>

java.lang.Object
  gnu.trove.impl.hash.THash
      gnu.trove.impl.hash.TObjectHash<T>

All Implemented Interfaces:

java.io.Externalizable, java.io.Serializable

Direct Known Subclasses:

THashMap, TObjectIntHashMap, TObjectLongHashMap

public abstract class TObjectHash<T>
extends THash

An open addressed hashing implementation for Object types.

Created: Sun Nov 4 08:56:06 2001

Version:

$Id: TObjectHash.java,v 1.1.2.6 2009/11/07 03:36:44 robeden Exp $

Author:

Eric D. Friedman, Rob Eden, Jeff Randall

See Also:

Serialized Form

Field Summary

java.lang.Object[]	_set the set of Objects
static java.lang.Object	FREE
static java.lang.Object	REMOVED

Fields inherited from class gnu.trove.impl.hash.THash

_autoCompactionFactor, _autoCompactRemovesRemaining, _autoCompactTemporaryDisable, _free, _loadFactor, _maxSize, _size, DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR

Constructor Summary

TObjectHash()
Creates a new TObjectHash instance with the default capacity and load factor.

TObjectHash(int initialCapacity)
Creates a new TObjectHash instance whose capacity is the next highest prime above initialCapacity + 1 unless that value is already prime.

TObjectHash(int initialCapacity, float loadFactor)
Creates a new TObjectHash instance with a prime value at or near the specified capacity and load factor.

Method Summary

int	capacity()
boolean	contains(java.lang.Object obj) Searches the set for obj
boolean	forEach(TObjectProcedure<T> procedure) Executes procedure for each element in the set.
protected int	index(java.lang.Object obj) Locates the index of obj.
protected int	insertionIndex(T obj) Locates the index at which obj can be inserted.
void	readExternal(java.io.ObjectInput in)
protected void	removeAt(int index) Delete the record at index.
int	setUp(int initialCapacity) initializes the Object set of this hash table.
protected void	throwObjectContractViolation(java.lang.Object o1, java.lang.Object o2) Convenience methods for subclasses to use in throwing exceptions about badly behaved user objects employed as keys.
void	writeExternal(java.io.ObjectOutput out)

Methods inherited from class gnu.trove.impl.hash.THash

calculateGrownCapacity, clear, compact, computeMaxSize, computeNextAutoCompactionAmount, ensureCapacity, getAutoCompactionFactor, isEmpty, postInsertHook, reenableAutoCompaction, rehash, setAutoCompactionFactor, size, tempDisableAutoCompaction, trimToSize

Methods inherited from class java.lang.Object

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

Field Detail

_set

public transient java.lang.Object[] _set

the set of Objects

REMOVED

public static final java.lang.Object REMOVED

FREE

public static final java.lang.Object FREE

Constructor Detail

TObjectHash

public TObjectHash()

Creates a new TObjectHash instance with the default capacity and load factor.

TObjectHash

public TObjectHash(int initialCapacity)

Creates a new TObjectHash instance whose capacity is the next highest prime above initialCapacity + 1 unless that value is already prime.

Parameters:

initialCapacity - an int value

TObjectHash

public TObjectHash(int initialCapacity,
                   float loadFactor)

Creates a new TObjectHash instance with a prime value at or near the specified capacity and load factor.

Parameters:

initialCapacity - used to find a prime capacity for the table.

loadFactor - used to calculate the threshold over which rehashing takes place.

Method Detail

capacity

public int capacity()

Specified by:

capacity in class THash

Returns:

the current physical capacity of the hash table.

contains

public boolean contains(java.lang.Object obj)

Searches the set for obj

Parameters:

obj - an Object value

Returns:

a boolean value

forEach

public boolean forEach(TObjectProcedure<T> procedure)

Executes procedure for each element in the set.

Parameters:

procedure - a TObjectProcedure value

Returns:

false if the loop over the set terminated because the procedure returned false for some value.

index

protected int index(java.lang.Object obj)

Locates the index of obj.

Parameters:

obj - an Object value

Returns:

the index of obj or -1 if it isn't in the set.

insertionIndex

protected int insertionIndex(T obj)

Locates the index at which obj can be inserted. if there is already a value equal()ing obj in the set, returns that value's index as -index - 1.

Parameters:

obj - an Object value

Returns:

the index of a FREE slot at which obj can be inserted or, if obj is already stored in the hash, the negative value of that index, minus 1: -index -1.

readExternal

public void readExternal(java.io.ObjectInput in)
                  throws java.io.IOException,
                         java.lang.ClassNotFoundException

Specified by:

readExternal in interface java.io.Externalizable

Overrides:

readExternal in class THash

Throws:

java.io.IOException

java.lang.ClassNotFoundException

removeAt

protected void removeAt(int index)

Description copied from class: THash

Delete the record at index. Reduces the size of the collection by one.

Overrides:

removeAt in class THash

Parameters:

index - an int value

setUp

public int setUp(int initialCapacity)

initializes the Object set of this hash table.

Overrides:

setUp in class THash

Parameters:

initialCapacity - an int value

Returns:

an int value

throwObjectContractViolation

protected final void throwObjectContractViolation(java.lang.Object o1,
                                                  java.lang.Object o2)
                                           throws java.lang.IllegalArgumentException

Convenience methods for subclasses to use in throwing exceptions about badly behaved user objects employed as keys. We have to throw an IllegalArgumentException with a rather verbose message telling the user that they need to fix their object implementation to conform to the general contract for java.lang.Object.

Parameters:

o1 - the first of the equal elements with unequal hash codes.

o2 - the second of the equal elements with unequal hash codes.

Throws:

java.lang.IllegalArgumentException - the whole point of this method.

writeExternal

public void writeExternal(java.io.ObjectOutput out)
                   throws java.io.IOException

Specified by:

writeExternal in interface java.io.Externalizable

Overrides:

writeExternal in class THash

Throws:

java.io.IOException