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package com.talk2object.util;

import java.util.ArrayList;
import java.util.Set;

public class ClassAssignmentUtils {
	public static final int INTERFACE_COST = 10000;
	public static final int OBJECT_COST = 20000;

	/**
	 * interface cost is more than class inheritance.
	 * 
	 * @param assigneeClass
	 * @param assignerClass
	 * @return -1 if not assignable. bigger means more inheritance levels.
	 */
	public static int getAssignmentCost(Class assigneeClass, Class assignerClass) {
		if (assigneeClass.isAssignableFrom(assignerClass)) {
			if (assigneeClass.isInterface()) {
				return INTERFACE_COST;
			} else {
				if (assigneeClass == Object.class)
					return OBJECT_COST;
				else
					return getInheritanceLevel(assigneeClass, assignerClass);
			}
		} else {
			return -1;
		}
	}

	/**
	 * 
	 * 
	 * @param assignee
	 * @param assigner
	 * @return
	 */
	public static int getInheritanceLevel(Class superClass, Class subClass) {

		int count = 0;
		Class tempClass = subClass;
		while (tempClass != superClass) {
			count++;
			tempClass = tempClass.getSuperclass();
		}

		if (count >= INTERFACE_COST)
			throw new RuntimeException("too many inheritance levels.");

		return count;
	}

}