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public final Class IntHashtable

extends Object
Class Inheritance
Simple internal class for doing hash mapping. Much, much faster than the standard Hashtable for integer to integer mappings, and doesn't require object creation.
If a key is not found, the defaultValue is returned.

Note

the keys are limited to values above Integer.MIN_VALUE+1.

Field Summary

Modifier and TypeField and Description
private int
count

private int
defaultValue

private static final int
DELETED

private static final int
EMPTY

private static final float
HIGH_WATER_FACTOR

private int
highWaterMark

private int[]
keyList

private static final float
LOW_WATER_FACTOR

private int
lowWaterMark

private static final int
MAX_UNUSED

private int
primeIndex

private static final int[]
PRIMES

private int[]
values

Constructor Summary

AccessConstructor and Description
public
IntHashtable()

public
IntHashtable(int initialSize)

Method Summary

Modifier and TypeMethod and Description
public Object
clone()

Overrides java.lang.Object.clone.

Creates and returns a copy of this object.

public boolean
equals(Object that)

Overrides java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.

private int
find(int key)

public int
get(int key)

public int
getDefaultValue()

public int
hashCode()

Overrides java.lang.Object.hashCode.

Returns a hash code value for this object.

private void
initialize(int primeIndex)

public boolean
isEmpty()

private static int
leastGreaterPrimeIndex(int source)

public void
put(int key, int value)

public void
putInternal(int key, int value)

private void
rehash()

public void
remove(int key)

public void
setDefaultValue(int newValue)

public int
size()

Inherited from java.lang.Object:
finalizegetClassnotifynotifyAlltoStringwaitwaitwait

Field Detail

countback to summary
private int count
defaultValueback to summary
private int defaultValue
DELETEDback to summary
private static final int DELETED
EMPTYback to summary
private static final int EMPTY
HIGH_WATER_FACTORback to summary
private static final float HIGH_WATER_FACTOR
highWaterMarkback to summary
private int highWaterMark
keyListback to summary
private int[] keyList
LOW_WATER_FACTORback to summary
private static final float LOW_WATER_FACTOR
lowWaterMarkback to summary
private int lowWaterMark
MAX_UNUSEDback to summary
private static final int MAX_UNUSED
primeIndexback to summary
private int primeIndex
PRIMESback to summary
private static final int[] PRIMES
valuesback to summary
private int[] values

Constructor Detail

IntHashtableback to summary
public IntHashtable()
IntHashtableback to summary
public IntHashtable(int initialSize)

Method Detail

cloneback to summary
public Object clone() throws CloneNotSupportedException

Overrides java.lang.Object.clone.

Doc from java.lang.Object.clone.

Creates and returns a copy of this object. The precise meaning of "copy" may depend on the class of the object. The general intent is that, for any object x, the expression: 

x.clone() != x
will be true, and that the expression: 
x.clone().getClass() == x.getClass()
will be true, but these are not absolute requirements. While it is typically the case that: 
x.clone().equals(x)
will be true, this is not an absolute requirement.

By convention, the returned object should be obtained by calling super.clone. If a class and all of its superclasses (except Object) obey this convention, it will be the case that x.clone().getClass() == x.getClass().

By convention, the object returned by this method should be independent of this object (which is being cloned). To achieve this independence, it may be necessary to modify one or more fields of the object returned by super.clone before returning it. Typically, this means copying any mutable objects that comprise the internal "deep structure" of the object being cloned and replacing the references to these objects with references to the copies. If a class contains only primitive fields or references to immutable objects, then it is usually the case that no fields in the object returned by super.clone need to be modified.

Exceptions
CloneNotSupportedException:
if the object's class does not support the Cloneable interface. Subclasses that override the clone method can also throw this exception to indicate that an instance cannot be cloned.
equalsback to summary
public boolean equals(Object that)

Overrides java.lang.Object.equals.

Doc from java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

  • It is reflexive: for any non-null reference value x, x.equals(x) should return true.
  • It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
  • It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
  • It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
  • For any non-null reference value x, x.equals(null) should return false.

An equivalence relation partitions the elements it operates on into equivalence classes; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes.

Annotations
@Override
findback to summary
private int find(int key)
getback to summary
public int get(int key)
getDefaultValueback to summary
public int getDefaultValue()
hashCodeback to summary
public int hashCode()

Overrides java.lang.Object.hashCode.

Doc from java.lang.Object.hashCode.

Returns a hash code value for this object. This method is supported for the benefit of hash tables such as those provided by java.util.HashMap.

The general contract of hashCode is:

  • Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
  • If two objects are equal according to the equals method, then calling the hashCode method on each of the two objects must produce the same integer result.
  • It is not required that if two objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.
Annotations
@Override
initializeback to summary
private void initialize(int primeIndex)
isEmptyback to summary
public boolean isEmpty()
leastGreaterPrimeIndexback to summary
private static int leastGreaterPrimeIndex(int source)
putback to summary
public void put(int key, int value)
putInternalback to summary
public void putInternal(int key, int value)
rehashback to summary
private void rehash()
removeback to summary
public void remove(int key)
setDefaultValueback to summary
public void setDefaultValue(int newValue)
sizeback to summary
public int size()