aljoscha commented on a change in pull request #14765: URL: https://github.com/apache/flink/pull/14765#discussion_r565454247
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/state/KeyValueStateIterator.java ########## @@ -0,0 +1,73 @@ +/* + * 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; + +/** + * Iterator that over all key-value state entries in a {@link KeyedStateBackend}. For use during + * snapshotting. + * + * <p>This is required to partition all states into contiguous key-groups. The resulting iteration + * sequence is ordered by (key-group, kv-state). + */ +public interface KeyValueStateIterator extends AutoCloseable { + + /** + * Advances the iterator. Should only be called if {@link #isValid()} returned true. Valid flag + * can only change after calling {@link #next()}. + */ + void next(); + + /** Returns the key-group for the current key. */ + int keyGroup(); + + byte[] key(); + + byte[] value(); + + /** Returns the Id of the K/V state to which the current key belongs. */ + int kvStateId(); + + /** + * Indicates if current key starts a new k/v-state, i.e. belong to a different k/v-state than + * it's predecessor. + * + * @return true iff the current key belong to a different k/v-state than it's predecessor. + */ + boolean isNewKeyValueState(); + + /** + * Indicates if current key starts a new key-group, i.e. belong to a different key-group than + * it's predecessor. + * + * @return true iff the current key belong to a different key-group than it's predecessor. + */ + boolean isNewKeyGroup(); + + /** + * Check if the iterator is still valid. Getters like {@link #key()}, {@link #value()}, etc. as + * well as {@link #next()} should only be called if valid returned true. Should be checked after + * each call to {@link #next()} before accessing iterator state. + * + * @return True iff this iterator is valid. + */ + boolean isValid(); + + @Override + void close(); Review comment: I kept this from `RocksStatesPerKeyGroupMergeIterator`, which also overrode `close()` without exception. And some of the code that uses it expects it not to throw. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
