flink

src/main/java/demo/SocketWindowWordCount.java

+package demo;
+
+import org.apache.flink.api.common.functions.FlatMapFunction;
+import org.apache.flink.api.common.functions.ReduceFunction;
+import org.apache.flink.api.java.utils.ParameterTool;
+import org.apache.flink.streaming.api.datastream.DataStream;
+import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
+import org.apache.flink.streaming.api.windowing.time.Time;
+import org.apache.flink.util.Collector;
+
+public class SocketWindowWordCount {
+
+    public static void main(String[] args) throws Exception {
+
+        // the port to connect to
+        final int port;
+        try {
+            final ParameterTool params = ParameterTool.fromArgs(args);
+            port = params.getInt("port");
+        } catch (Exception e) {
+            System.err.println("No port specified. Please run 'SocketWindowWordCount --port <port>'");
+            return;
+        }
+
+        // get the execution environment
+        final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
+
+        // get input data by connecting to the socket
+        DataStream<String> text = env.socketTextStream("localhost", port, "\n");
+
+        // parse the data, group it, window it, and aggregate the counts
+        DataStream<WordWithCount> windowCounts = text
+                .flatMap(new FlatMapFunction<String, WordWithCount>() {
+                    @Override
+                    public void flatMap(String value, Collector<WordWithCount> out) {
+                        for (String word : value.split("\\s")) {
+                            out.collect(new WordWithCount(word, 1L));
+                        }
+                    }
+                })
+                .keyBy("word")
+                .timeWindow(Time.seconds(5), Time.seconds(1))
+                .reduce(new ReduceFunction<WordWithCount>() {
+                    @Override
+                    public WordWithCount reduce(WordWithCount a, WordWithCount b) {
+                        return new WordWithCount(a.word, a.count + b.count);
+                    }
+                });
+
+        // print the results with a single thread, rather than in parallel
+        windowCounts.print().setParallelism(1);
+
+        env.execute("Socket Window WordCount");
+    }
+
+    // Data type for words with count
+    public static class WordWithCount {
+
+        public String word;
+        public long count;
+
+        public WordWithCount() {}
+
+        public WordWithCount(String word, long count) {
+            this.word = word;
+            this.count = count;
+        }
+
+        @Override
+        public String toString() {
+            return word + " : " + count;
+        }
+    }
+}