presto-example-http/src/main/java/io/prestosql/plugin/example/ExampleClient.java/ExampleClient/lookupSchemas
class ExampleClient:    private static Map<String, Map<String, ExampleTable>> lookupSchemas(URI metadataUri, JsonCodec<Map<String, List<ExampleTable>>> catalogCodec)
            throws IOException
    {
        URL result = metadataUri.toURL();
        String json = Resources.toString(result, UTF_8);
        Map<String, List<ExampleTable>> catalog = catalogCodec.fromJson(json);

        return ImmutableMap.copyOf(transformValues(catalog, resolveAndIndexTables(metadataUri)));
    }