fj.data.HashSet Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of functionaljava Show documentation
Show all versions of functionaljava Show documentation
Functional Java is an open source library that supports closures for the Java programming language
package fj.data;
import fj.Equal;
import fj.Hash;
import fj.Unit;
import static fj.Unit.unit;
import java.util.Collection;
import java.util.Iterator;
/**
* A mutable hash set that guarantees uniqueness of its elements providing O(1) lookup.
*
* @version %build.number%
* @see HashMap
*/
public final class HashSet implements Iterable {
/**
* Returns an iterator for this hash set. This method exists to permit the use in a for-each loop.
*
* @return A iterator for this hash set.
*/
public Iterator iterator() {
return toCollection().iterator();
}
private final HashMap m;
/**
* Construct a hash set with the given equality and hashing strategy.
*
* @param e The equality strategy.
* @param h The hashing strategy.
*/
public HashSet(final Equal e, final Hash h) {
m = new HashMap(e, h);
}
/**
* Construct a hash set with the given equality and hashing strategy.
*
* @param e The equality strategy.
* @param h The hashing strategy.
* @param initialCapacity The initial capacity.
*/
public HashSet(final Equal e, final Hash h, final int initialCapacity) {
m = new HashMap(e, h, initialCapacity);
}
/**
* Construct a hash set with the given equality and hashing strategy.
*
* @param e The equality strategy.
* @param h The hashing strategy.
* @param initialCapacity The initial capacity.
* @param loadFactor The load factor.
*/
public HashSet(final Equal e, final Hash h, final int initialCapacity, final float loadFactor) {
m = new HashMap(e, h, initialCapacity, loadFactor);
}
/**
* Compare two values for equality using the underlying equality strategy.
*
* @param a1 One value to compare.
* @param a2 The other value to compare.
* @return true if the two values are equal, false otherwise.
*/
public boolean eq(final A a1, final A a2) {
return m.eq(a1, a2);
}
/**
* Compute the hash of the given value using the underlying hashing strategy.
*
* @param a The value to computer the hash of.
* @return The hash of the given value.
*/
public int hash(final A a) {
return m.hash(a);
}
/**
* Determines if this hash set contains the given element.
*
* @param a The element to look for in this hash set.
* @return true if this hash set contains the given element, false otherwise.
*/
public boolean contains(final A a) {
return m.contains(a);
}
/**
* Insert the given element into this hash set.
*
* @param a The element to insert.
*/
public void set(final A a) {
m.set(a, unit());
}
/**
* Clear all elements from this hash set.
*/
public void clear() {
m.clear();
}
/**
* Determines if this hash set contains any elements.
*
* @return true if this hash set contains no elements, false otherwise.
*/
public boolean isEmpty() {
return m.isEmpty();
}
/**
* Returns the number of entries in this hash set.
*
* @return The number of entries in this hash set.
*/
public int size() {
return m.size();
}
/**
* Deletes the given element from this hash set.
*
* @param a The element to delete from this hash set.
* @return true if this hash set contained the given element prior to deletion, false
* otherwise.
*/
public boolean delete(final A a) {
return m.getDelete(a).isSome();
}
/**
* Returns a list projection of this hash set.
*
* @return A list projection of this hash set.
*/
public List toList() {
return m.keys();
}
/**
* Projects an immutable collection of this hash set.
*
* @return An immutable collection of this hash set.
*/
public Collection toCollection() {
return toList().toCollection();
}
}