import java.util.*;

/**
 * Adapts a set to contain only shapes of type AShape.
 * @author Jeff Raab
 */
public class SetOfAShape {

    /** Set containing shapes. */
    private JavaSet shapes = new JavaSet();
    
    /** Constructs an empty set of shapes. */
    public SetOfAShape() {}
    
    /**
     * Adds the given shape to this.
     * @param anAShape shape to be added
     */
    public void add(AShape anAShape) {
        shapes.add(anAShape);
    }
    
    /**
     * Removes the given shape from this.
     * @param anAShape shape to be removed
     */
    public void remove(AShape anAShape) {
        shapes.remove(anAShape);
    }
    
    /**
     * Sets this to its union with the given set.
     * @param aSet set with which to union
     */
    public void union(SetOfAShape aSet) {
        shapes.union(aSet.shapes);
    }
    
    /**
     * Sets this to its intersection with the given set.
     * @param aSet set with which to intersect
     */
    public void intersection(SetOfAShape aSet) {
        shapes.intersection(aSet.shapes);
    }
    
    /** Returns the number of shapes in this. */
    public int size() {
        return shapes.size();
    }
    
    /** 
     * Returns whether or not this contains the given shape.
     * @param anAShape shape to compare with contents of this
     */
    public boolean contains(AShape anAShape) {
        return shapes.contains(anAShape);
    }
    
    /** 
     * Returns whether or not the given object equals this.
     * @param anObject object to compare with this
     */
    public boolean equals(Object anObject) {
        return shapes.equals(anObject);
    }
    
    /** Returns an item in this. */
    public AShape item() {
        return (AShape)shapes.item();
    }
    
    /** Returns an enumeration of the contents of this. */
    public Enumeration elements() {
        return shapes.elements();
    }
}