Github user fhueske commented on a diff in the pull request: https://github.com/apache/flink/pull/5441#discussion_r167949288 --- Diff: flink-libraries/flink-sql-client/src/main/java/org/apache/flink/table/client/gateway/DynamicResult.java --- @@ -0,0 +1,253 @@ +/* + * 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.table.client.gateway; + +import org.apache.flink.api.java.tuple.Tuple2; +import org.apache.flink.table.sinks.TableSink; +import org.apache.flink.types.Row; + +import java.net.InetAddress; +import java.util.ArrayList; +import java.util.HashMap; +import java.util.List; +import java.util.Map; + +/** + * A result of a dynamic table program. + */ +public class DynamicResult { + + private final boolean isChangelog; + private final CollectTableSink collectTableSink; + private final Object resultLock = new Object(); + private final ResultRetrievalThread retrievalThread; + private final JobMonitoringThread monitoringThread; + private Runnable program; + private SqlExecutionException executionException; + + // for table materialization + private final List<Row> materializedTable; + private final Map<Row, List<Integer>> rowPositions; // positions of rows in table for faster access + private final List<Row> snapshot; + private int pageSize; + private boolean isLastSnapshot; + + // for changelog + private Tuple2<Boolean, Row> nextChangeRecord; + + public DynamicResult(InetAddress targetAddress, int targetPort, boolean isChangelog) { + this.isChangelog = isChangelog; + + // create table sink + collectTableSink = new CollectTableSink(targetAddress, targetPort); + retrievalThread = new ResultRetrievalThread(); + monitoringThread = new JobMonitoringThread(); + + // prepare for table materialization + materializedTable = new ArrayList<>(); + rowPositions = new HashMap<>(); + snapshot = new ArrayList<>(); + isLastSnapshot = false; + } + + public boolean isChangelog() { + return isChangelog; + } + + public void startRetrieval(Runnable program) { + // start listener thread + retrievalThread.start(); + + // start program + this.program = program; + monitoringThread.start(); + } + + public TypedResult<Tuple2<Boolean, Row>> retrieveRecord() { + synchronized (resultLock) { + // retrieval thread is alive return a record if available + // but the program must not have failed + if (retrievalThread.isRunning && executionException == null) { + if (nextChangeRecord == null) { + return TypedResult.empty(); + } else { + final Tuple2<Boolean, Row> change = nextChangeRecord; + nextChangeRecord = null; + resultLock.notify(); + return TypedResult.payload(change); + } + } + // retrieval thread is dead but there is still a record to be delivered + else if (!retrievalThread.isRunning && nextChangeRecord != null) { + final Tuple2<Boolean, Row> change = nextChangeRecord; + nextChangeRecord = null; + return TypedResult.payload(change); + } + // no results can be returned anymore + else { + return handleMissingResult(); + } + } + } + + public TypedResult<Integer> snapshot(int pageSize) { + synchronized (resultLock) { + // retrieval thread is dead and there are no results anymore + // or program failed + if ((!retrievalThread.isRunning && isLastSnapshot) || executionException != null) { + return handleMissingResult(); + } + // this snapshot is the last result that can be delivered + else if (!retrievalThread.isRunning) { + isLastSnapshot = true; + } + + this.pageSize = pageSize; + snapshot.clear(); + snapshot.addAll(materializedTable); + + // at least one page + final int pageCount = Math.max(1, (int) Math.ceil(((double) snapshot.size() / pageSize))); + return TypedResult.payload(pageCount); + } + } + + public List<Row> retrievePage(int page) { + final int pageCount = Math.max(1, (int) Math.ceil(((double) snapshot.size()) / pageSize)); --- End diff -- pageCount could be remembered
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