@Override
  public Schema getSchema(Type type) {
    Schema schema = schemas.get(type);

    if (schema == null) {
      synchronized (schemas) {
        schema = schemas.get(type);
        if (schema == null) {
          schema = new SchemaImpl(ensureResourceProvider(type));
          schemas.put(type, schema);
        }
      }
    }

    return schema;
  }
Check whether properties specified with a @SortRequest are supported by
the @ResourceProvider.

@param sortRequest @SortRequest
@param type @Type
@param provider @ResourceProvider
@throws UnsupportedPropertyException
ambari-server/src/main/java/org/apache/ambari/server/controller/internal/ClusterControllerImpl.java