Adding Java versions of Pi and LogQuery

examples/src/main/java/spark/examples/JavaLogQuery.java

+package spark.examples;
+
+import com.google.common.collect.Lists;
+import scala.Tuple2;
+import scala.Tuple3;
+import spark.api.java.JavaPairRDD;
+import spark.api.java.JavaRDD;
+import spark.api.java.JavaSparkContext;
+import spark.api.java.function.Function2;
+import spark.api.java.function.PairFunction;
+
+import java.io.Serializable;
+import java.util.Collections;
+import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * Executes a roll up-style query against Apache logs.
+ */
+public class JavaLogQuery {
+
+    public static List<String> exampleApacheLogs = Lists.newArrayList(
+            "10.10.10.10 - \"FRED\" [18/Jan/2013:17:56:07 +1100] \"GET http://images.com/2013/Generic.jpg " +
+            "HTTP/1.1\" 304 315 \"http://referall.com/\" \"Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; GTB7.4; .NET CLR 2.0.50727; " +
+            ".NET CLR 3.0.04506.30; .NET CLR 3.0.04506.648; .NET CLR 3.5.21022; .NET CLR 3.0.4506.2152; .NET CLR 1.0.3705; .NET CLR 1.1.4322; .NET CLR " +
+            "3.5.30729; Release=ARP)\" \"UD-1\" - \"image/jpeg\" \"whatever\" 0.350 \"-\" - \"\" 265 923 934 \"\" " +
+            "62.24.11.25 images.com 1358492167 - Whatup",
+            "10.10.10.10 - \"FRED\" [18/Jan/2013:18:02:37 +1100] \"GET http://images.com/2013/Generic.jpg " +
+            "HTTP/1.1\" 304 306 \"http:/referall.com\" \"Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; " +
+            "GTB7.4; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.04506.648; .NET CLR " +
+            "3.5.21022; .NET CLR 3.0.4506.2152; .NET CLR 1.0.3705; .NET CLR 1.1.4322; .NET CLR  " +
+            "3.5.30729; Release=ARP)\" \"UD-1\" - \"image/jpeg\" \"whatever\" 0.352 \"-\" - \"\" 256 977 988 \"\" " +
+            "0 73.23.2.15 images.com 1358492557 - Whatup");
+
+
+    public static Pattern apacheLogRegex = Pattern.compile("^([\\d.]+) (\\S+) (\\S+) \\[([\\w\\d:/]+\\s[+\\-]\\d{4})\\] \"(.+?)\" (\\d{3}) ([\\d\\-]+) \"([^\"]+)\" \"([^\"]+)\".*");
+
+    /** Tracks the total query count and number of aggregate bytes for a particular group. */
+    public static class Stats implements Serializable {
+
+        private int count;
+        private int numBytes;
+
+        public Stats(int count, int numBytes) {
+            this.count = count;
+            this.numBytes = numBytes;
+        }
+        public Stats merge(Stats other) {
+            return new Stats(count + other.count, numBytes + other.numBytes);
+        }
+
+        public String toString() {
+            return String.format("bytes=%s\tn=%s", numBytes, count);
+        }
+    }
+
+    public static Tuple3<String, String, String> extractKey(String line) {
+        Matcher m = apacheLogRegex.matcher(line);
+        List<String> key = Collections.emptyList();
+        if (m.find()) {
+            String ip = m.group(1);
+            String user = m.group(3);
+            String query = m.group(5);
+            if (!user.equalsIgnoreCase("-")) {
+                return new Tuple3<String, String, String>(ip, user, query);
+            }
+        }
+        return new Tuple3<String, String, String>(null, null, null);
+    }
+
+    public static Stats extractStats(String line) {
+        Matcher m = apacheLogRegex.matcher(line);
+        if (m.find()) {
+            int bytes = Integer.parseInt(m.group(7));
+            return new Stats(1, bytes);
+        }
+        else
+            return new Stats(1, 0);
+    }
+
+    public static void main(String[] args) throws Exception {
+        if (args.length == 0) {
+            System.err.println("Usage: JavaLogQuery <master> [logFile]");
+            System.exit(1);
+        }
+
+        JavaSparkContext jsc = new JavaSparkContext(args[0], "JavaLogQuery",
+               System.getenv("SPARK_HOME"), System.getenv("SPARK_EXAMPLES_JAR"));
+
+        JavaRDD<String> dataSet = (args.length == 2) ? jsc.textFile(args[1]) : jsc.parallelize(exampleApacheLogs);
+
+        JavaPairRDD<Tuple3<String, String, String>, Stats> extracted = dataSet.map(new PairFunction<String, Tuple3<String, String, String>, Stats>() {
+            @Override
+            public Tuple2<Tuple3<String, String, String>, Stats> call(String s) throws Exception {
+                return new Tuple2<Tuple3<String, String, String>, Stats>(extractKey(s), extractStats(s));
+            }
+        });
+
+        JavaPairRDD<Tuple3<String, String, String>, Stats> counts = extracted.reduceByKey(new Function2<Stats, Stats, Stats>() {
+            @Override
+            public Stats call(Stats stats, Stats stats2) throws Exception {
+                return stats.merge(stats2);
+            }
+        });
+
+        List<Tuple2<Tuple3<String, String, String>, Stats>> output = counts.collect();
+        for (Tuple2 t : output) {
+            System.out.println(t._1 + "\t" + t._2);
+        }
+        System.exit(0);
+    }
+}

examples/src/main/java/spark/examples/JavaSparkPi.java

+package spark.examples;
+
+import spark.api.java.JavaRDD;
+import spark.api.java.JavaSparkContext;
+import spark.api.java.function.Function;
+import spark.api.java.function.Function2;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/** Computes an approximation to pi */
+public class JavaSparkPi {
+
+    public static void main(String[] args) throws Exception {
+        if (args.length == 0) {
+            System.err.println("Usage: JavaLogQuery <master> [slices]");
+            System.exit(1);
+        }
+
+        JavaSparkContext jsc = new JavaSparkContext(args[0], "JavaLogQuery",
+                System.getenv("SPARK_HOME"), System.getenv("SPARK_EXAMPLES_JAR"));
+
+        int slices = (args.length == 2) ? Integer.parseInt(args[1]) : 2;
+        int n = 100000 * slices;
+        List<Integer> l = new ArrayList<Integer>(n);
+        for (int i = 0; i < n; i++)
+            l.add(i);
+
+        JavaRDD<Integer> dataSet = jsc.parallelize(l, slices);
+
+        int count = dataSet.map(new Function<Integer, Integer>() {
+            @Override
+            public Integer call(Integer integer) throws Exception {
+                double x = Math.random() * 2 - 1;
+                double y = Math.random() * 2 - 1;
+                return (x * x + y * y < 1) ? 1 : 0;
+            }
+        }).reduce(new Function2<Integer, Integer, Integer>() {
+            @Override
+            public Integer call(Integer integer, Integer integer2) throws Exception {
+                return integer + integer2;
+            }
+        });
+
+        System.out.println("Pi is roughly " + 4.0 * count / n);
+    }
+}

examples/src/main/scala/spark/examples/SparkPi.scala

@@ -4,6 +4,7 @@ import scala.math.random
 import spark._
 import SparkContext._
 
+/** Computes an approximation to pi */
 object SparkPi {
   def main(args: Array[String]) {
     if (args.length == 0) {