/* * Copyright (c) 2017, 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. */ /** * This package contains classes for consuming Flight Recorder data. *
* In the following example, the program prints a histogram of all method samples in a recording. *
*
* 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("com.oracle.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());
* }
* }
*
*
* * Null-handling *
* 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}. * * @commercialFeature * @since 9 */ package jdk.jfr.consumer;