SortedSet.java

package assign08;

import java.util.ArrayList;
import java.util.Collection;
import java.util.NoSuchElementException;

/**
 * An interface for representing a sorted set of generically-typed items. By
 * definition, a set contains no duplicate items. The items are ordered using
 * their natural ordering (i.e., each item must be Comparable). Note that this
 * interface is much like Java's SortedSet, but simpler.
 * 
 * @author Erin Parker
 * @version March 17, 2021
 */
public interface SortedSet<Type extends Comparable<? super Type>> {

	/**
	 * Ensures that this set contains the specified item.
	 * 
	 * @param item - the item whose presence is ensured in this set
	 * @return true if this set changed as a result of this method call (that is, if
	 *         the input item was actually inserted); otherwise, returns false
	 */
	public boolean add(Type item);

	/**
	 * Ensures that this set contains all items in the specified collection.
	 * 
	 * @param items - the collection of items whose presence is ensured in this set
	 * @return true if this set changed as a result of this method call (that is, if
	 *         any item in the input collection was actually inserted); otherwise,
	 *         returns false
	 */
	public boolean addAll(Collection<? extends Type> items);

	/**
	 * Removes all items from this set. The set will be empty after this method
	 * call.
	 */
	public void clear();

	/**
	 * Determines if there is an item in this set that is equal to the specified
	 * item.
	 * 
	 * @param item - the item sought in this set
	 * @return true if there is an item in this set that is equal to the input item;
	 *         otherwise, returns false
	 */
	public boolean contains(Type item);

	/**
	 * Determines if for each item in the specified collection, there is an item in
	 * this set that is equal to it.
	 * 
	 * @param items - the collection of items sought in this set
	 * @return true if for each item in the specified collection, there is an item
	 *         in this set that is equal to it; otherwise, returns false
	 */
	public boolean containsAll(Collection<? extends Type> items);

	/**
	 * Returns the first (i.e., smallest) item in this set.
	 * 
	 * @throws NoSuchElementException if the set is empty
	 */
	public Type first() throws NoSuchElementException;

	/**
	 * Returns true if this set contains no items.
	 */
	public boolean isEmpty();

	/**
	 * Returns the last (i.e., largest) item in this set.
	 * 
	 * @throws NoSuchElementException if the set is empty
	 */
	public Type last() throws NoSuchElementException;

	/**
	 * Ensures that this set does not contain the specified item.
	 * 
	 * @param item - the item whose absence is ensured in this set
	 * @return true if this set changed as a result of this method call (that is, if
	 *         the input item was actually removed); otherwise, returns false
	 */
	public boolean remove(Type item);

	/**
	 * Ensures that this set does not contain any of the items in the specified
	 * collection.
	 * 
	 * @param items - the collection of items whose absence is ensured in this set
	 * @return true if this set changed as a result of this method call (that is, if
	 *         any item in the input collection was actually removed); otherwise,
	 *         returns false
	 */
	public boolean removeAll(Collection<? extends Type> items);

	/**
	 * Returns the number of items in this set.
	 */
	public int size();

	/**
	 * Returns an ArrayList containing all of the items in this set, in sorted
	 * order.
	 */
	public ArrayList<Type> toArrayList();
}