Method checkNonNullComparable

src/java/org/apache/poi/util/BinaryTree.java:1198–1211

check if an object is fit to be proper input ... has to be Comparable and non-null @param o the object being checked @param index _KEY or _VALUE (used to put the right word in the exception message) @exception NullPointerException if o is null @exception ClassCastException if o is not

(Object o,
                                               int index)

     * @exception ClassCastException if o is not Comparable
     */
    private static void checkNonNullComparable(Object o,
                                               int index)
    {
        if (o == null)
        {
            throw new NullPointerException(_data_name[ index ]
                                           + " cannot be null");
        }
        if (!(o instanceof Comparable))
        {
            throw new ClassCastException(_data_name[ index ]
                                         + " must be Comparable");
        }
    }

    /**
     * check a key for validity (non-null and implements Comparable)