/*
 *     file: Inference.java
 *  package: oreilly.hcj.tiger
 *
 * This software is granted under the terms of the Common Public License,
 * CPL, which may be found at the following URL:
 * http://www-124.ibm.com/developerworks/oss/CPLv1.0.htm
 *
 * Copyright(c) 2003-2005 by the authors indicated in the @author tags.
 * All Rights are Reserved by the various authors.
 *
########## DO NOT EDIT ABOVE THIS LINE ########## */
package oreilly.hcj.tiger;

import java.util.*;
import java.io.Serializable;

/** 
 * Implements a manager of lists that stores the lists by
 * key.
 */
public class InferenceDemo {
	static int callCount = 0;

	/** First. */	
	public static <Type> Type someMethod(final Type obj) {
		System.out.print("First==> ");
		return obj;
	}

	/** Second. */	
	public static <Type extends Number> Type someMethod(final Type num) {
		System.out.print("Second==> ");
		return num;
	}

	/** Third. */	
	public static <Type> Type someMethod(final Type obj, List<Type> list) {
		System.out.print("Third==> ");
		return obj;
	}

	/** Fourth. */	
	public static <Type> List<Type> someMethod() {
		System.out.print("Fourth==> ");
		return new ArrayList<Type>();
	}

	/** Fifth. */	
	public static void someMethod(final Object obj) {
		System.out.print("Fifth==> ");
	}

	/** Sixth. */	
 	public static void someMethod(final String str) {
		System.out.print("Sixth==> ");
	}

	/** Seventh. */	
	public static <Type> Type someOtherMethod(final Type obj, List<? extends Type> list) {
		System.out.print("Seventh==> ");
		return obj;
	}

	/** Demonstrate the rules. */
	public final static void main(final String[] args) {
		System.out.println();

		// Picks Sixth
		System.out.print("\n1) ");
		someMethod("Hello");

		// Ambiguous, wont compile.
		//System.out.print("\n2) ");
		//someMethod(new C());

		// Ambiguous, wont compile.
		// First and Fifth mask each other and can never be called.
		//System.out.print("\n3) ");
		//someMethod(new Object());

		// Picks Second
		System.out.print("\n5) ");
		someMethod(new Integer(5));

		// Picks Second
		System.out.print("\n6) ");
		someMethod(5);

		// Picks Fourth
		System.out.print("\n7) ");
		List<Integer> listOne = someMethod();
		listOne.add(new Integer(5));

		System.out.print("\n7a) ");
		List<String> listTwo = someMethod();
		listTwo.add(new String("Hello"));

		System.out.print("\n7b) ");
		Object listThree = someMethod();
		System.out.println(listThree.getClass());
		//listThree.add( ... );  // Cant put anything into this list

		// -- Make some lists --
		List<A> listOfA = new ArrayList<A>();
		listOfA.add(new A());

		List<B> listOfB = new ArrayList<B>();
		listOfB.add(new B());
		
		// Picks 
		System.out.print("\n8) ");
		someMethod(5, new ArrayList<Integer>());

		// Wont compile: No such type. Since A can not necessarily be promoted to B.
		//System.out.print("9) ");
		//someMethod(new A(), listOfB);

		// Picks Three: Works because B can be demoted to A
		System.out.print("\n10) ");
		someMethod(new B(), listOfA);

		// Picks Seventh
		System.out.print("\n11) ");
		someOtherMethod(new A(), listOfB);

		// Picks Seventh
		// Works even though it probably shouldnt. The someOtherMethod() signature implies
		// that the type of the component of the ist should be a subtype of the type used
		// for obj. However, in this case first is a List<A> and A clearly isnt a subtype
		// of B. Is this a bug?
		System.out.print("\n12) ");
		someOtherMethod(new B(), listOfA);

		// Really weird as the two types arent even remotely related. This should probably
		// be rejected by the compiler but it doesnt seem to be enforcing its bounds. 
		System.out.print("\n13) ");
		List<String> listOfString = new ArrayList<String>();
		listOfString.add("Hello");
		someOtherMethod(new Integer(5), listOfString);

		// Doesnt work even though the spec says it should: 
		//System.out.print(I"14)");
		//A value = <A>someMethod(new B(), new ArrayList<A>());

		// Picks Fourth: The type of the list returned by SomeMethod is List<Integer> 
		System.out.print("\n15) ");
		someMethod(5, someMethod());

		// Picks Fourth: The type of the list returned by SomeMethod is List<String> 
		System.out.print("\n16) ");
		someMethod("Hello", someMethod());
	}

	private static class A {
	}

	private static class B extends A {
	}

	private static class C extends B {
	}
}

/* ########## End of File ########## */