import java.util.*;

public class MultiHashMapTest {

    /** Objects to be used as keys */
    private static final Object o1 = new Object();
    private static final Object o2 = new Object();
    private static final Object o3 = new Object();
    private static final Object o4 = new Object();

    /** Strings to be used as values */
    private static final String s1 = "one";
    private static final String s2 = "two";
    private static final String s3 = "three";
    private static final String s4 = "four";

    /** Collections to be used to test */
    private static final Collection c12 = new Vector();
    private static final Collection c12n = new Vector();

    /** Main entry point to program */
    public static void main(String[] args) {
	setupCollections();

	try {
	    testMHM();
	} catch (Exception excn) {
	    excn.printStackTrace();
	}
    }

    public static void setupCollections() {
	c12.add(s1);
	c12.add(s2);

	c12n.addAll(c12);
	c12n.add(null);
    }

    public static void testMHM() throws CheckFailedException {

	MultiHashMap mhm = new MultiHashMap();
	check("Assigning value to a key that was not in before", mhm.put(o1, s1) == null);
	check("Verifying association caused by put", s1.equals(mhm.get(o1)));
	check("Verifying return value when reassigning a key to a value", s1.equals(mhm.put(o1, s2)));
	checkEqualCollection("Verifying getAll method", c12, mhm.getAll(o1));
	mhm.putAll(o3, c12);
	checkEqualCollection("Verifying putAll method", c12, mhm.getAll(o3));
	mhm.put(o3, null);
	checkEqualCollection("Verifying the ability to add null values with put method", c12n, mhm.getAll(o3));
	check("Verifying the contains method works for null", mhm.contains(o3, null));
	check("Verifying the contains method works", mhm.contains(o3, s1));
	check("Verifying remove method return value", mhm.remove(o3, null));
	check("Verifying remove method works", !mhm.contains(o3, null));
	checkEqualCollection("Verifying HashMap remove method return value", (Collection) mhm.remove(o3), c12);
	check("Verifying HashMap remove method works", mhm.get(o3) == null);
    }
    
    public static void check(String message, boolean result) throws CheckFailedException {
	if (result == false)
	    throw new CheckFailedException(message + " failed");
	else
	    System.out.println(message + " passed");
    }

    public static void checkEqualCollection(String message, Collection c1, Collection c2) throws CheckFailedException {
	check(message, c1.containsAll(c2) && c2.containsAll(c1));
    }

    private static class CheckFailedException extends Exception {
	public CheckFailedException() { super(); }
	public CheckFailedException(String message) { super(message); }
    }
}