flink-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From shixiaogang <...@git.apache.org>
Subject [GitHub] flink pull request #3336: [FLINK-4856][state] Add MapState in KeyedState
Date Mon, 20 Feb 2017 01:37:29 GMT
Github user shixiaogang commented on a diff in the pull request:

    https://github.com/apache/flink/pull/3336#discussion_r101936792
  
    --- Diff: flink-core/src/main/java/org/apache/flink/api/common/state/MapState.java ---
    @@ -0,0 +1,111 @@
    +/*
    + * Licensed to the Apache Software Foundation (ASF) under one
    + * or more contributor license agreements.  See the NOTICE file
    + * distributed with this work for additional information
    + * regarding copyright ownership.  The ASF licenses this file
    + * to you under the Apache License, Version 2.0 (the
    + * "License"); you may not use this file except in compliance
    + * with the License.  You may obtain a copy of the License at
    + *
    + *     http://www.apache.org/licenses/LICENSE-2.0
    + *
    + * Unless required by applicable law or agreed to in writing, software
    + * distributed under the License is distributed on an "AS IS" BASIS,
    + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    + * See the License for the specific language governing permissions and
    + * limitations under the License.
    + */
    +
    +package org.apache.flink.api.common.state;
    +
    +import org.apache.flink.annotation.PublicEvolving;
    +
    +import java.io.IOException;
    +import java.util.Iterator;
    +import java.util.Map;
    +
    +/**
    + * {@link State} interface for partitioned key-value state. The key-value pair can be
    + * added, updated and retrieved.
    + *
    + * <p>The state is accessed and modified by user functions, and checkpointed consistently
    + * by the system as part of the distributed snapshots.
    + *
    + * <p>The state is only accessible by functions applied on a KeyedDataStream. The
key is
    + * automatically supplied by the system, so the function always sees the value mapped
to the
    + * key of the current element. That way, the system can handle stream and state partitioning
    + * consistently together.
    + *
    + * @param <UK> Type of the keys in the state.
    + * @param <UV> Type of the values in the state.
    + */
    +@PublicEvolving
    +public interface MapState<UK, UV> extends AppendingState<Map<UK, UV>,
Iterable<Map.Entry<UK, UV>>> {
    --- End diff --
    
    `MapState` provides the `add` method which puts a collection of key-value pairs into the
state. Though the semantics may be a little different in existing `AppendingState`s, I think
it's okay for `MapState` to be an `AppendingState` because the interface does not enforce
any restriction on the modification of previous data.


---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastructure@apache.org or file a JIRA ticket
with INFRA.
---

Mime
View raw message