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ASF GitHub Bot commented on FLINK-5041: --------------------------------------- Github user StephanEwen commented on a diff in the pull request: https://github.com/apache/flink/pull/2781#discussion_r91076224 --- Diff: flink-runtime/src/main/java/org/apache/flink/runtime/state/MultiStreamStateHandle.java --- @@ -0,0 +1,96 @@ +/* + * 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.runtime.state; + +import org.apache.flink.core.fs.AbstractMultiFSDataInputStream; +import org.apache.flink.core.fs.FSDataInputStream; +import org.apache.flink.util.Preconditions; + +import java.io.IOException; +import java.util.List; +import java.util.Map; +import java.util.TreeMap; + +/** + * Wrapper class that takes multiple {@link StreamStateHandle} and makes them look like a single one. This is done by + * providing a contiguous view on all the streams of the inner handles through a wrapper stream and by summing up all + * all the meta data. + */ +public class MultiStreamStateHandle implements StreamStateHandle { + + private static final long serialVersionUID = -4588701089489569707L; + private final List<StreamStateHandle> stateHandles; + private final long stateSize; + + public MultiStreamStateHandle(List<StreamStateHandle> stateHandles) throws IOException { --- End diff -- Would be good to either reject empty lists, or add a test that validates that this works with empty lists of streams. > Implement savepoint backwards compatibility 1.1 -> 1.2 > ------------------------------------------------------ > > Key: FLINK-5041 > URL: https://issues.apache.org/jira/browse/FLINK-5041 > Project: Flink > Issue Type: New Feature > Components: State Backends, Checkpointing > Affects Versions: 1.2.0 > Reporter: Stefan Richter > Assignee: Stefan Richter > > This issue tracks the implementation of backwards compatibility between Flink > 1.1 and 1.2 releases. > This task subsumes: > - Converting old savepoints to new savepoints, including a conversion of > state handles to their new replacement. > - Converting keyed state from old backend implementations to their new > counterparts. > - Converting operator and function state for all changed operators. -- This message was sent by Atlassian JIRA (v6.3.4#6332)