Java Distance Calculate distance(final Class child, final Class parent)

Description

Gets derivation distance of an object<br> Possible values are:<br> - -1 = child !instanceof parent<br> - 0 = child is the same class as the parent one<br> - greater than 0 = child is the nth of the parent<br> <br> Copied from<br> https://github.com/apache/commons-lang/blob/master/src/main/java/org/apache/commons/lang3/reflect/InheritanceUtils.java

License

Open Source License

Parameter

Parameter	Description
child	Child class
parent	Parent class

Declaration

public static int distance(final Class<?> child, final Class<?> parent) 

Method Source Code

//package com.java2s;
//License from project: Open Source License 

public class Main {
    /**//from   ww w  .j av a 2 s .c  o  m
     * Gets derivation distance of an object<br>
     * Possible values are:<br>
     * - -1 = child !instanceof parent<br>
     * - 0 = child is the same class as the parent one<br>
     * - greater than 0 = child is the nth of the parent<br>
     * <br>
     * Copied from<br>
     * https://github.com/apache/commons-lang/blob/master/src/main/java/org/apache/commons/lang3/reflect/InheritanceUtils.java
     * @param child Child class
     * @param parent Parent class
     * @return
     */
    public static int distance(final Class<?> child, final Class<?> parent) {
        if (child == null || parent == null) {
            return -1;
        }

        if (child.equals(parent)) {
            return 0;
        }

        final Class<?> cParent = child.getSuperclass();
        int d = parent.equals(cParent) ? 1 : 0;

        if (cParent != null) {
            Class<?>[] interfaces = cParent.getInterfaces();
            for (Class<?> i : interfaces) {
                if (parent.equals(i))
                    d = 1;

            }
        }

        if (d == 1) {
            return d;
        }
        d += distance(cParent, parent);
        return d > 0 ? d + 1 : -1;
    }
}

Related

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6. distance(final double x, final double y)
7. distance(final double x1, final double y1, final double x2, final double y2)
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9. distance(final double[] a, final double[] b)