1 files changed, 44 insertions, 0 deletions
diff --git a/src/main/java/dev/morling/onebrc/CalculateAverage.java b/src/main/java/dev/morling/onebrc/CalculateAverage.java
new file mode 100644
index 0000000..7672d75
--- /dev/null
+++ b/src/main/java/dev/morling/onebrc/CalculateAverage.java
@@ -0,0 +1,44 @@
+/*
+ *  Copyright 2023 The original authors
+ *
+ *  Licensed 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 dev.morling.onebrc;
+
+import static java.util.stream.Collectors.averagingDouble;
+import static java.util.stream.Collectors.groupingBy;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.Map;
+import java.util.TreeMap;
+import java.util.stream.Collectors;
+
+public class CalculateAverage {
+
+    private static final String FILE = "./measurements.txt";
+
+    public static void main(String[] args) throws IOException {
+        Map<String, Double> measurements = Files.lines(Paths.get(FILE))
+                .limit(10_000_000)
+                .map(l -> l.split(";"))
+                .collect(groupingBy(m -> m[0], averagingDouble(m -> Double.parseDouble(m[1]))));
+
+        measurements = new TreeMap<>(measurements.entrySet()
+                .stream()
+                .collect(Collectors.toMap(e -> e.getKey(), e -> Math.round(e.getValue() * 10.0) / 10.0)));
+
+        System.out.println(measurements);
+    }
+}