src/jdk.jfr/share/classes/jdk/jfr/consumer/package-info.java
changeset 50113 caf115bb98ad
child 53016 9f13f8aad8dc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.jfr/share/classes/jdk/jfr/consumer/package-info.java	Tue May 15 20:24:34 2018 +0200
@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2017, 2018, 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.
+ */
+
+/**
+ * This package contains classes for consuming Flight Recorder data.
+ * <p>
+ * In the following example, the program prints a histogram of all method samples in a recording.
+ * <pre>
+ * <code>
+ *   public static void main(String[] args) {
+ *     if (args.length != 0) {
+ *       System.out.println("Must specify recording file.");
+ *       return;
+ *     }
+ *     try (RecordingFile f = new RecordingFile(Paths.get(args[0]))) {
+ *       Map{@literal <}String, SimpleEntry{@literal <}String, Integer{@literal >}{@literal >} histogram = new HashMap{@literal <}{@literal >}();
+ *       int total = 0;
+ *       while (f.hasMoreEvents()) {
+ *         RecordedEvent event = f.readEvent();
+ *         if (event.getEventType().getName().equals("jdk.ExecutionSample")) {
+ *           RecordedStackTrace s = event.getStackTrace();
+ *           if (s != null) {
+ *             RecordedFrame topFrame= s.getFrames().get(0);
+ *             if (topFrame.isJavaFrame())  {
+ *               RecordedMethod method = topFrame.getMethod();
+ *               String methodName = method.getType().getName() + "#" + method.getName() + " " + method.getDescriptor();
+ *               Entry entry = histogram.computeIfAbsent(methodName, u -{@literal >} new SimpleEntry{@literal <}String, Integer{@literal >}(methodName, 0));
+ *               entry.setValue(entry.getValue() + 1);
+ *               total++;
+ *             }
+ *           }
+ *         }
+ *       }
+ *       List{@literal <}SimpleEntry{@literal <}String, Integer{@literal >}{@literal >} entries = new ArrayList{@literal <}{@literal >}(histogram.values());
+ *       entries.sort((u, v) -{@literal >} v.getValue().compareTo(u.getValue()));
+ *       for (SimpleEntry{@literal <}String, Integer{@literal >} c : entries) {
+ *         System.out.printf("%2.0f%% %s\n", 100 * (float) c.getValue() / total, c.getKey());
+ *       }
+ *       System.out.println("\nSample count: " + total);
+ *     } catch (IOException ioe) {
+ *       System.out.println("Error reading file " + args[0] + ". " + ioe.getMessage());
+ *     }
+ *   }
+ * </code>
+ * </pre>
+ * <p>
+ * <b>Null-handling</b>
+ * <p>
+ * All methods define whether they accept or return {@code null} in the Javadoc.
+ * Typically this is expressed as {@code "not null"}. If a {@code null}
+ * parameter is used where it is not allowed, a
+ * {@code java.lang.NullPointerException} is thrown. If a {@code null}
+ * parameters is passed to a method that throws other exceptions, such as
+ * {@code java.io.IOException}, the {@code java.lang.NullPointerException} takes
+ * precedence, unless the Javadoc for the method explicitly states how
+ * {@code null} is handled, i.e. by throwing {@code java.lang.IllegalArgumentException}.
+ *
+ * @since 9
+ */
+package jdk.jfr.consumer;