HashSet.java
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package org.hsqldb.lib;
import org.hsqldb.map.BaseHashMap;
/**
* This class does not store null keys.
*
* @author Fred Toussi (fredt@users dot sourceforge.net)
* @version 2.7.3
* @since 1.7.2
*/
public class HashSet<E> extends BaseHashMap implements Set<E> {
public HashSet() {
this(8);
}
public HashSet(int initialCapacity) throws IllegalArgumentException {
super(
initialCapacity,
BaseHashMap.objectKeyOrValue,
BaseHashMap.noKeyOrValue,
false);
}
public HashSet(
int initialCapacity,
ObjectComparator<E> comparator)
throws IllegalArgumentException {
this(initialCapacity);
this.comparator = comparator;
}
public HashSet(E[] valueList) {
this(valueList.length);
for (int i = 0; i < valueList.length; i++) {
add(valueList[i]);
}
}
public boolean contains(Object key) {
return super.containsObjectKey(key);
}
public boolean containsAll(Collection<E> col) {
Iterator<E> it = col.iterator();
while (it.hasNext()) {
if (contains(it.next())) {
continue;
}
return false;
}
return true;
}
/** returns existing value or null if added
* can be used as an Object cache
*/
public E getOrAdd(E key) {
if (key == null) {
throw new NullPointerException();
}
E value = get(key);
if (value == null) {
value = key;
add(key);
}
return value;
}
public E get(E key) {
if (key == null) {
throw new NullPointerException();
}
int lookup = getLookup(key);
if (lookup < 0) {
return null;
} else {
return (E) objectKeyTable[lookup];
}
}
/**
* returns true if element is added
*
* @param key the element
* @return true if added
*/
public boolean add(E key) {
if (key == null) {
throw new NullPointerException();
}
return (Boolean) super.addOrUpdate(0, 0, key, null);
}
/** returns true if any element is added
*
* @param c the Collection to add
* @return true if any element is added
*/
public boolean addAll(Collection<? extends E> c) {
boolean changed = false;
Iterator<? extends E> it = c.iterator();
while (it.hasNext()) {
changed |= add(it.next());
}
return changed;
}
/** returns true if any element is added
*
* @param keys the array of elements to add
* @return true if any element is added
*/
public boolean addAll(E[] keys) {
boolean changed = false;
for (int i = 0; i < keys.length; i++) {
changed |= add(keys[i]);
}
return changed;
}
/**
* returns true if any added
*
* @param keys array of keys to add
* @param start first index to add
* @param limit limit of index to add
* @return true if any element was added
*/
public boolean addAll(E[] keys, int start, int limit) {
boolean changed = false;
for (int i = start; i < keys.length && i < limit; i++) {
changed |= add(keys[i]);
}
return changed;
}
/**
* returns true if removed
*
* @param key Object to remove
* @return true if removed
*/
public boolean remove(E key) {
if (key == null) {
throw new NullPointerException();
}
return super.removeObject(key, false) != null;
}
/**
* returns true if all were removed
*
* @param c Collection of elements to remove
* @return true if all removed
*/
public boolean removeAll(Collection<E> c) {
Iterator<E> it = c.iterator();
boolean result = true;
while (it.hasNext()) {
result &= remove(it.next());
}
return result;
}
/**
* returns true if all were removed
*
* @param keys E[]
* @return boolean
*/
public boolean removeAll(E[] keys) {
boolean result = true;
for (int i = 0; i < keys.length; i++) {
result &= remove(keys[i]);
}
return result;
}
public int capacity() {
return super.capacity();
}
public int getCommonElementCount(Set<E> other) {
int count = 0;
Iterator<E> it = iterator();
while (it.hasNext()) {
if (other.contains(it.next())) {
count++;
}
}
return count;
}
public <T> T[] toArray(T[] a) {
return toArray(a, true);
}
public Object[] toArray() {
return toArray(true);
}
public Iterator<E> iterator() {
return new BaseHashIterator(true);
}
/**
* Returns a String like "[Drei, zwei, Eins]", exactly like
* java.util.HashSet.
*
* @return String representation
*/
public String toString() {
Iterator<E> it = iterator();
StringBuilder sb = new StringBuilder();
sb.append('[');
while (it.hasNext()) {
if (sb.length() > 1) {
sb.append(", ");
}
sb.append(it.next());
}
sb.append(']');
return sb.toString();
}
}