private static Object typeCastValue(final String key, final String value, final Map<String, String> keyTypes) {
        final String type = keyTypes.get(key);
        if (null == type || type.equals(GraphMLTokens.STRING))
            return value;
        else if (type.equals(GraphMLTokens.FLOAT))
            return Float.valueOf(value);
        else if (type.equals(GraphMLTokens.INT))
            return Integer.valueOf(value);
        else if (type.equals(GraphMLTokens.DOUBLE))
            return Double.valueOf(value);
        else if (type.equals(GraphMLTokens.BOOLEAN))
            return Boolean.valueOf(value);
        else if (type.equals(GraphMLTokens.LONG))
            return Long.valueOf(value);
        else
            return value;
    }
This method is not supported for this reader.

@throws UnsupportedOperationException when called.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/io/graphml/GraphMLReader.java