Class ArraySet

src/main/java/pascal/taie/util/collection/ArraySet.java:36–190

Set implementation based on ArrayList. This class should only be used for small set. Elements cannot be null. Note that remove(Object) will shift the rest elements to the end. TODO: if necessary, optimize remove(Object) and let add(Object) add element to empty hole of the array.

 *  element to empty hole of the array.
 */
public class ArraySet<E> extends AbstractSetEx<E>
        implements Serializable {

    public static final int DEFAULT_CAPACITY = 8;

    private static final String NULL_MESSAGE = "ArraySet does not permit null element";

    private final ArrayList<E> elements;

    private final int initialCapacity;

    private final boolean fixedCapacity;

    public ArraySet() {
        this(DEFAULT_CAPACITY, true);
    }

    public ArraySet(int initialCapacity) {
        this(initialCapacity, true);
    }

    public ArraySet(int initialCapacity, boolean fixedCapacity) {
        this.initialCapacity = initialCapacity;
        this.fixedCapacity = fixedCapacity;
        elements = new ArrayList<>(initialCapacity);
    }

    /**
     * Takes given array list as elements.
     * Note that the caller should ensure that {@code elements} contains
     * no duplicate elements.
     */
    public ArraySet(ArrayList<E> elements, boolean fixedCapacity) {
        // assert new java.util.HashSet<>(elements).size() == elements.size();
        this.elements = elements;
        this.initialCapacity = elements.size();
        this.fixedCapacity = fixedCapacity;
    }

    public ArraySet(Collection<? extends E> coll) {
        this(coll.size(), false);
        addAll(coll);
    }

    @Override
    public boolean isEmpty() {
        return elements.isEmpty();
    }

    @Override
    public boolean contains(Object o) {
        return elements.contains(o);
    }

    @Override
    @Nonnull
    public Object[] toArray() {
        return elements.toArray();