static int hashCodeElem(Object elem) {
	    if (elem == null) {
	        return 0;
	    } else {
	        return elem.hashCode();
	    }
	}
Helper method to calculate hash code of a element stored in the list.

@param elem	element
@return		hash code for element
jphp-runtime/src/php/runtime/memory/support/IList.java