+ * 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("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}. + * + * @since 8 + */ +package jdk.jfr.consumer;