// The IMaps class defines static methods for the IMap<K,V> type.
// In particular, it defines a static factory method for creating the
// empty map of the IMap<K,V> type.

import java.util.Iterator;

class IMaps {

    private static IMap theEmptyIMap = new IMapList();

    // static factory method for creating an empty IMap<K,V>

    @SuppressWarnings("unchecked")
    public static <K,V> IMap<K,V> empty () {
        return (IMap<K,V>) theEmptyIMap;
    }

    // main method for testing

    public static void main (String[] args) {
        IMapTests.main (args);
    }
}

// Tests for IMap<K,V> objects.

class IMapTests {

    public static void main (String[] args) {
	IMap<Integer,String> m0 = IMaps.empty();
	IMap<Integer,String> m1 = m0.extend (1, "one");
	IMap<Integer,String> m2 = m0.extend (2, "two");
	IMap<Integer,String> m3 = m0.extend (3, "three");
	IMap<Integer,String> m4 = m0.extend (4, "four");
	IMap<Integer,String> m5 = m0.extend (5, "five");
	IMap<Integer,String> m6 = m0.extend (6, "six");
	IMap<Integer,String> m7 = m0.extend (7, "seven");
	IMap<Integer,String> m8 = m0.extend (8, "eight");
	IMap<Integer,String> m9 = m0.extend (9, "nine");

	IMap<Integer,String> m00 = IMaps.empty();
	IMap<Integer,String> m03 = m9.extend (3, "drei");
	IMap<Integer,String> m10 = m03.extend (10, "zehn");

	assert ! m0.containsKey(1);
	assert m9.containsKey(4);
	assert ! m9.containsKey(10);

	assert m9.get(9).equals("nine");
	assert m9.get(3).equals("three");
	assert m9.get(1).equals("one");

	assert m10.get(9).equals("nine");
	assert m10.get(3).equals("drei");
	assert m10.get(1).equals("one");

	assert m0.isEmpty();
	assert ! m1.isEmpty();

	assert m0.size() == 0;
	assert m1.size() == 1;
	assert m9.size() == 9;
	assert m03.size() == 9;
	assert m10.size() == 10;

        System.out.println ("IMap tests passed.");
    }
}