@Test
    public void testGet() {
        assertNull( get( new BasicDBObject( "foo", null ), "foo" ) );
        assertEquals( get( new BasicDBObject( "foo", "bar" ), "foo" ), "bar" );

        assertNull( get( new BasicDBObject( "foo", new BasicDBObject( "bar", null ) ), "foo.bar" ) );
        assertEquals( get( new BasicDBObject( "foo", new BasicDBObject( "bar", "baz" ) ), "foo.bar" ), "baz" );
    }

    @Test
    public void testPut() {
        BasicDBObject dbo = new BasicDBObject();
        put( dbo, "foo", null );
        assertNull( get( dbo, "foo" ) );

        dbo = new BasicDBObject();
        put( dbo, "foo", "bar" );
        assertEquals( get( dbo, "foo" ), "bar" );

        dbo = new BasicDBObject();
        put( dbo, "foo.bar", null );
        assertNull( get( dbo, "foo.bar" ) );

        dbo = new BasicDBObject();
        put( dbo, "foo.bar", "baz" );
        assertEquals( get( dbo, "foo.bar" ), "baz" );
    }

    /**
     * Gets the specified property (use dots for specifying an object/property graph) from the given {@link DBObject}.
     * @param <T> the type of the desired result.
     * @param dbo the dbobject.
     * @param key the key or path of keys separated by dots.
     * @return the result or <code>null</code>.
     */
    @CheckForNull
    @SuppressWarnings( "unchecked" )
    public static <T> T get( @Nonnull final DBObject dbo, @Nonnull final String key ) {
        final String[] keys = key.split( "\\." );
        DBObject current = dbo;
        Object result = null;
        for ( int i = 0; i < keys.length; i++ ) {
            result = current.get( keys[i] );
            if ( i + 1 < keys.length ) {
                current = (DBObject) result;
            }
        }
        return (T) result;
    }

    /**
     * Sets the given value for the specified key (or the last key if a property path was
     * specified using dot-notation) on the given {@link DBObject}.
     * @param dbo the dbobject to set the value.
     * @param key the key or path of keys separated by dots.
     * @return the previous value associated with <tt>key</tt>, or
     *         <tt>null</tt> if there was no mapping for <tt>key</tt>.
     *         (A <tt>null</tt> return can also indicate that the map
     *         previously associated <tt>null</tt> with <tt>key</tt>.)
     */
    @CheckForNull
    public static Object put( @Nonnull final DBObject dbo, @Nonnull final String key, @Nullable final Object value ) {
        final String[] keys = key.split( "\\." );
        DBObject current = dbo;
        for ( int i = 0; i + 1 < keys.length; i++ ) {
            DBObject child = (DBObject) current.get( keys[i] );
            if ( child == null ) {
                child = new BasicDBObject();
                current.put( keys[i], child );
            }
            current = child;
        }
        return current.put( keys[keys.length - 1], value );
    }