<![CDATA[
// Quick and dirty implementation of HashSet. handout #37
public class HashSet<E> {
private HashNode[] entries;
private int size;
public HashSet(int capacity) {
// set up array with load factor of 0.75
entries = new HashNode[(int) (capacity / 0.75)];
}
public void add(E value) {
if (!contains(value)) {
int i = indexOf(value);
entries[i] = new HashNode(value, entries[i]);
size++;
}
}
public boolean contains(E value) {
int i = indexOf(value);
HashNode current = entries[i];
while (current != null) {
if (current.data.equals(value))
return true;
current = current.next;
}
return false;
}
public void remove(E value) {
if (contains(value)) {
int i = indexOf(value);
if (entries[i].data.equals(value))
entries[i] = entries[i].next;
else {
HashNode current = entries[i];
while (!current.next.data.equals(value))
current = current.next;
current.next = current.next.next;
}
size--;
}
}
public int size() {
return size;
}
private int indexOf(E value) {
return Math.abs(value.hashCode() % entries.length);
}
private static class HashNode {
public Object data;
public HashNode next;
public HashNode(Object data, HashNode next) {
this.data = data;
this.next = next;
}
}
}
]]>