Class HashSetLinear

java.lang.Object

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  +--java.util.AbstractCollection

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        +--java.util.AbstractSet

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              +--HashSetLinear

public class HashSetLinear

extends java.util.AbstractSet

This class implements a hash set with linear probing. It extends AbstractSet, with a implementations of add(), remove(), size() and iterator(). The iterator supports hasNext(), next(), and remove().

The element null cannot be stored in a HashSetLinear.

The iterators returned by this version of HashSetLinear are "failsafe": this is implemented by maintaining a modification counter. The Math 176 homework solutions do not need to support this feature.

One novel feature of this implementation is that it supports active deletion (which is not generally used with linear probing).

The objects in the set must support equals() and hashCode(). Two objects which test as being equal should have the same hash code. Otherwise, unpredictable results may occur.

Constructor Summary

HashSetLinear()
This constuctor creates a new, empty HashSetLinear with an initial capacity of 101 and a load factor of 0.50.

HashSetLinear(int initialCapacity)
This constuctor creates a new, empty HashSetLinear with a specified initial capacity and the default load factor of 0.50.

HashSetLinear(int initialCapacity, float loadFactor)
This constuctor creates a new, empty HashSetLinear with a specified initial capacity and a specified load factor.

Method Summary

boolean	add(java.lang.Object o) Add an object to the set stored in the HashTableLinear.
void	clear() Removes all the elements from the set (not necessary for Math 176 homework).
boolean	contains(java.lang.Object o) Check whether an object is present in the hash table
java.util.Iterator	iterator() Create an iterator for the HashTableLinear set
boolean	remove(java.lang.Object o) Remove an object from the set stored in the HashTableLinear.
int	size() Return the number of elements in the hash table

Methods inherited from class java.util.AbstractSet

equals, hashCode

Methods inherited from class java.util.AbstractCollection

addAll, containsAll, isEmpty, removeAll, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

HashSetLinear

public HashSetLinear()

This constuctor creates a new, empty HashSetLinear with an initial capacity of 101 and a load factor of 0.50.

HashSetLinear

public HashSetLinear(int initialCapacity)

This constuctor creates a new, empty HashSetLinear with a specified initial capacity and the default load factor of 0.50.

Parameters:

initialCapacity - inital size of the hash table

Throws:

java.lang.IllegalArgumentException - if the initial capacity is negative.

HashSetLinear

public HashSetLinear(int initialCapacity,
                     float loadFactor)

This constuctor creates a new, empty HashSetLinear with a specified initial capacity and a specified load factor. The hash set will be resized whenever the number of elements exceeds the size of the hashtable times the load factor. The present implementation never resizes downwards.

Parameters:

initialCapacity - inital size of the hash table

loadFactor - the load factor: not recommended to be higher than 0.75.

Throws:

java.lang.IllegalArgumentException - if the initial capacity is negative or if the loadFactor is not greater than zero and less than one.

Method Detail

iterator

public java.util.Iterator iterator()

Create an iterator for the HashTableLinear set

Overrides:

iterator in class java.util.AbstractCollection

size

public int size()

Return the number of elements in the hash table

Overrides:

size in class java.util.AbstractCollection

contains

public boolean contains(java.lang.Object o)

Check whether an object is present in the hash table

Overrides:

contains in class java.util.AbstractCollection

Parameters:

o - The Object whose presence is being checked.

Returns:

true if o is in the set.

add

public boolean add(java.lang.Object o)

Add an object to the set stored in the HashTableLinear. An object that is already present in the set will not be re-added. Thus the set never contains duplicate copies of the same object. The hash table will be resized if the addition of one more element would exceed the resize threshold.

Overrides:

add in class java.util.AbstractCollection

Parameters:

o - the Object to be added.

Returns:

true if the object was added, i.e., if the object was not already present in the set.

remove

public boolean remove(java.lang.Object o)

Remove an object from the set stored in the HashTableLinear.

Overrides:

remove in class java.util.AbstractCollection

Parameters:

o - the Object to be removed

Returns:

true if the object was removed, i.e., returns true if the object was present in the set to be removed.

clear

public void clear()

Removes all the elements from the set (not necessary for Math 176 homework).

Overrides:

clear in class java.util.AbstractCollection