--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.jfr/share/classes/jdk/jfr/consumer/UseCasesStream.java Fri May 17 18:03:14 2019 +0200
@@ -0,0 +1,193 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.jfr.consumer;
+
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.text.ParseException;
+import java.time.Duration;
+import java.util.ArrayDeque;
+
+import jdk.jfr.Configuration;
+import jdk.jfr.EventType;
+import jdk.jfr.ValueDescriptor;
+
+class UseCasesStream {
+
+ //
+ // Use case: Out-of-the-Box Experience
+ //
+ // - Simple things should be simple
+ // - Pique interest, i.e. a one-liner on Stack Overflow
+ // - Few lines of code as possible
+ // - Should be easier than alternative technologies, like JMX and JVM TI
+ //
+ // - Non-goals: Corner-cases, advanced configuration, releasing resources
+ //
+ public static void outOfTheBox() throws Exception {
+ try (RecordingStream rs = new RecordingStream()) {
+ rs.enable("jdk.ExceptionThrown");
+ rs.onEvent(e -> System.out.println(e.getString("message")));
+ rs.start();
+ }
+
+ // EventStream.start("jdk.JavaMonitorEnter", "threshold", "20 ms",
+ // "stackTrace", "false")
+ // .addConsumer(System.out::println);
+ //
+ // EventStream.start("jdk.CPULoad", "period", "1 s")
+ // .addConsumer(e -> System.out.println(100 *
+ // e.getDouble("totalMachine") + " %"));
+ //
+ // EventStream.start("jdk.GarbageCollection")
+ // .addConsumer(e -> System.out.println("GC: " + e.getStartTime() + "
+ // maxPauseTime=" + e.getDuration("maxPauseTime").toMillis() + " ms"));
+
+ Thread.sleep(100_000);
+ }
+
+ // Use case: Event Forwarding
+ //
+ // - Forward arbitrary event to frameworks such as RxJava, JSON/XML and
+ // Kafka
+ // - Handle flooding
+ // - Performant
+ // - Graceful shutdown
+ // - Non-goals: Filter events
+ //
+ public static void eventForwarding() throws InterruptedException, IOException, ParseException {
+ // KafkaProducer producer = new KafkaProducer<String, String>();
+ try (RecordingStream rs = new RecordingStream(Configuration.getConfiguration("default"))) {
+ rs.setMaxAge(Duration.ofMinutes(5));
+ rs.setMaxSize(1000_000_000L);
+ // es.setParallel(true);
+ // es.setReuse(true);
+ // es.consume(e -> producer.send(new ProducerRecord<String,
+ // String>("topic",
+ // e.getString("key"), e.getString("value"))));
+ rs.start();
+ }
+ // Write primitive values to XML
+ try (RecordingStream rs = new RecordingStream(Configuration.getConfiguration("deafult"))) {
+ try (PrintWriter p = new PrintWriter(new FileWriter("recording.xml"))) {
+ // es.setParallel(false);
+ // es.setReuse(true);
+ p.println("<?xml version=\"1.0\" encoding=\"UTF-8\" ?>");
+ p.println("<events>");
+ rs.onEvent(e -> {
+ EventType type = e.getEventType();
+ p.println(" <event type=\"" + type.getName() + "\" start=\"" + e.getStartTime() + "\" end=\"" + e.getEndTime() + "\">");
+ for (ValueDescriptor field : e.getEventType().getFields()) {
+ Object value = e.getValue(field.getName());
+ if (value instanceof Number || field.getTypeName().equals("java.lang.String")) {
+ p.println(" <value field=\"" + field.getName() + "\">" + value + "</value>");
+ }
+ }
+ });
+ rs.start();
+ p.println("</events>");
+ }
+ }
+ }
+
+ // Use case: Repository Access
+ //
+ // - Read the disk repository from another process, for example a side car
+ // in
+ // Docker container
+ // - Be able to configure flush interval from command line or jcmd.
+ // - Graceful shutdown
+ //
+ public static void repositoryAccess() throws IOException, InterruptedException {
+ Path repository = Paths.get("c:\\repository").toAbsolutePath();
+ String command = new String();
+ command += "java -XX:StartFlightRecording:flush=2s";
+ command += "-XX:FlightRecorderOption:repository=" + repository + " Application";
+ Process myProcess = Runtime.getRuntime().exec(command);
+ try (RecordingStream rs = new RecordingStream()) {
+ rs.onEvent(System.out::println);
+ rs.startAsync();
+ Thread.sleep(10_000);
+ myProcess.destroy();
+ Thread.sleep(10_000);
+ }
+ }
+
+ // Use: Tooling
+ //
+ // - Monitor a stream of data for a very long time
+ // - Predictable interval, i.e. once every second
+ // - Notification with minimal delay
+ // - Events with the same period should arrive together
+ // - Consume events in chronological order
+ // - Low overhead
+ //
+ public static void tooling() throws IOException, ParseException {
+ ArrayDeque<Double> measurements = new ArrayDeque<>();
+ try (RecordingStream rs = new RecordingStream(Configuration.getConfiguration("profile"))) {
+ rs.setInterval(Duration.ofSeconds(1));
+ rs.setMaxAge(Duration.ofMinutes(1));
+ // rs.setOrdered(true);
+ // rs.setReuse(false);
+ // rs.setParallel(true);
+ rs.onEvent("jdk.CPULoad", e -> {
+ double d = e.getDouble("totalMachine");
+ measurements.addFirst(d);
+ if (measurements.size() > 60) {
+ measurements.removeLast();
+ }
+ // repaint();
+ });
+ rs.start();
+ }
+ }
+
+ // Use case: Low Impact
+ //
+ // - Support event subscriptions in a low latency environment (minimal GC
+ // pauses)
+ // - Filter out relevant events to minimize disk overhead and allocation
+ // pressure
+ // - Avoid impact from other recordings
+ // - Avoid Heisenberg effects, in particular self-recursion
+ //
+ // Non-goals: one-liner
+ //
+ public static void lowImpact() throws InterruptedException, IOException, ParseException {
+ try (RecordingStream rs = new RecordingStream()) {
+ rs.enable("jdk.JavaMonitorEnter#threshold").withThreshold(Duration.ofMillis(10));
+ rs.enable("jdk.ExceptionThrow#enabled");
+ // ep.setReuse(true);
+ rs.onEvent("jdk.JavaMonitorEnter", System.out::println);
+ rs.onEvent("jdk.ExceptionThrow", System.out::println);
+ rs.start();
+ ;
+ }
+ }
+}