Java Distance Calculate distanceToClass(Class<?> theClass, Class<?> theAncestor)

Description

Compute the hierarchical distance between the given class and an ancestor class.

License

LGPL

Parameter

Parameter	Description
theClass	the class to check.
theAncestor	the ancestor class.

Return

0 if the two parameters are equals, to 1 if the class directly extends the ancestor and is incremented by 1 for each ancestor between the class and its ancestor.

Declaration

public static int distanceToClass(Class<?> theClass, Class<?> theAncestor)

Method Source Code

//package com.java2s;
//License from project: LGPL 

public class Main {
    /**//from   w  w  w .j  a v  a 2  s.c  o m
     * Compute the hierarchical distance between the given class and an ancestor class. 
     * The hierarchical distance is equals to <code>0</code> if the two parameters are equals, 
     * to <code>1</code> if the class directly extends the ancestor
     * and is incremented by <code>1</code> for each ancestor between the class and its ancestor.<br>
     * If the given class is not a sub class of the ancestor, the result is <code>-1</code>.
     * @param theClass the class to check.
     * @param theAncestor the ancestor class.
     * @return <code>0</code> if the two parameters are equals, 
     * to <code>1</code> if the class directly extends the ancestor
     * and is incremented by <code>1</code> for each ancestor between the class and its ancestor.
     * @see #isSubClass(Class, Class)
     */
    public static int distanceToClass(Class<?> theClass, Class<?> theAncestor) {

        Class<?> superClass = null;

        if ((theClass != null) && (theAncestor != null) && (!theAncestor.isInterface())) {

            // If the ancestor and the current class are equals, the distance is 0
            if (theAncestor.equals(theClass)) {
                return 0;
            }

            // Search if the ancestor is directly declared on the class itself as super class. In this case,
            // the method return true. If the ancestor is not declared within the given class, 
            // its class hierarchy is recursively processed.
            superClass = theClass.getSuperclass();

            if (superClass != null) {

                if (superClass.equals(theAncestor)) {
                    return 1;
                } else {
                    // the ancestor was not the direct super class,
                    // the search is done following the class hierarchy
                    int tmp = distanceToClass(theClass.getSuperclass(), theAncestor);

                    if (tmp > -1) {
                        return 1 + tmp;
                    }
                }
            }
            superClass = null;
        }

        return -1;
    }
}

Java Distance Calculate distanceToClass(Class theClass, Class theAncestor)