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 * accompanied this code).

 *

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package jdk.jfr.event.metadata;

import java.io.IOException;

import java.lang.reflect.Field;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.util.Arrays;

import java.util.HashSet;

import java.util.List;

import java.util.Set;

import java.util.stream.Collectors;

import java.util.stream.Stream;

import jdk.jfr.EventType;

import jdk.jfr.Experimental;

import jdk.jfr.FlightRecorder;

import jdk.test.lib.Utils;

import jdk.test.lib.jfr.EventNames;

/**

 * @test Check for JFR events not covered by tests

 * @key jfr

 * @requires vm.hasJFR

 * @library /test/lib /test/jdk

 * @run main jdk.jfr.event.metadata.TestLookForUntestedEvents

 */

public class TestLookForUntestedEvents {

    private static final Path jfrTestRoot = Paths.get(Utils.TEST_SRC).getParent().getParent();

    private static final String MSG_SEPARATOR = "==========================";

    private static Set<String> jfrEventTypes = new HashSet<>();

    private static final Set<String> hardToTestEvents = new HashSet<>(

        Arrays.asList(

            "DataLoss", "IntFlag", "ReservedStackActivation",

            "DoubleFlag", "UnsignedLongFlagChanged", "IntFlagChanged",

            "UnsignedIntFlag", "UnsignedIntFlagChanged", "DoubleFlagChanged")

    );

    // GC uses specific framework to test the events, instead of using event names literally.

    // GC tests were inspected, as well as runtime output of GC tests.

    // The following events below are know to be covered based on that inspection.

    private static final Set<String> coveredGcEvents = new HashSet<>(

        Arrays.asList(

            "MetaspaceGCThreshold", "MetaspaceAllocationFailure", "MetaspaceOOM",

            "MetaspaceChunkFreeListSummary", "G1HeapSummary", "ParallelOldGarbageCollection",

            "OldGarbageCollection", "G1GarbageCollection", "GCPhasePause",

            "GCPhasePauseLevel1", "GCPhasePauseLevel2", "GCPhasePauseLevel3",

            "GCPhasePauseLevel4", "GCPhaseConcurrent")

    );

    // This is a "known failure list" for this test.

    // NOTE: if the event is not covered, a bug should be open, and bug number

    // noted in the comments for this set.

    private static final Set<String> knownNotCoveredEvents = new HashSet<>(

        // DumpReason: JDK-8213918

        Arrays.asList("DumpReason")

    );

    public static void main(String[] args) throws Exception {

        for (EventType type : FlightRecorder.getFlightRecorder().getEventTypes()) {

            if (type.getAnnotation(Experimental.class) == null) {

                jfrEventTypes.add(type.getName().replace("jdk.", ""));

            }

        }

        checkEventNamesClass();

        lookForEventsNotCoveredByTests();

    }

    // Look thru JFR tests to make sure JFR events are referenced in the tests

    private static void lookForEventsNotCoveredByTests() throws Exception {

        List<Path> paths = Files.walk(jfrTestRoot)

            .filter(Files::isRegularFile)

            .filter(path -> isJavaFile(path))

            .collect(Collectors.toList());

        Set<String> eventsNotCoveredByTest = new HashSet<>(jfrEventTypes);

        for (String event : jfrEventTypes) {

            for (Path p : paths) {

                if (findStringInFile(p, event)) {

                    eventsNotCoveredByTest.remove(event);

                    break;

                }

            }

        }

        // Account for hard-to-test, experimental and GC tested events

        eventsNotCoveredByTest.removeAll(hardToTestEvents);

        eventsNotCoveredByTest.removeAll(coveredGcEvents);

        eventsNotCoveredByTest.removeAll(knownNotCoveredEvents);

        if (!eventsNotCoveredByTest.isEmpty()) {

            print(MSG_SEPARATOR + " Events not covered by test");

            for (String event: eventsNotCoveredByTest) {

                print(event);

            }

            print(MSG_SEPARATOR);

            throw new RuntimeException("Found JFR events not covered by tests");

        }

    }

    // Make sure all the JFR events are accounted for in jdk.test.lib.jfr.EventNames

    private static void checkEventNamesClass() throws Exception {

        // jdk.test.lib.jfr.EventNames

        Set<String> eventsFromEventNamesClass = new HashSet<>();

        for (Field f : EventNames.class.getFields()) {

            String name = f.getName();

            if (!name.equals("PREFIX")) {

                String eventName = (String) f.get(null);

                eventName = eventName.replace(EventNames.PREFIX, "");

                eventsFromEventNamesClass.add(eventName);

            }

        }

        if (!jfrEventTypes.equals(eventsFromEventNamesClass)) {

            String exceptionMsg = "Events declared in jdk.test.lib.jfr.EventNames differ " +

                         "from events returned by FlightRecorder.getEventTypes()";

            print(MSG_SEPARATOR);

            print(exceptionMsg);

            print("");

            printSetDiff(jfrEventTypes, eventsFromEventNamesClass,

                        "jfrEventTypes", "eventsFromEventNamesClass");

            print("");

            print("This could be because:");

            print("1) You forgot to write a unit test. Please do so in test/jdk/jdk/jfr/event/");

            print("2) You wrote a unit test, but you didn't reference the event in");

            print("   test/lib/jdk/test/lib/jfr/EventNames.java. ");

            print("3) It is not feasible to test the event, not even a sanity test. ");

            print("   Add the event name to test/lib/jdk/test/lib/jfr/EventNames.java ");

            print("   and a short comment why it can't be tested");

            print("4) The event is experimental. Please add 'experimental=\"true\"' to <Event> ");

            print("   element in metadata.xml if it is a native event, or @Experimental if it is a ");

            print("   Java event. The event will now not show up in JMC");

            System.out.println(MSG_SEPARATOR);

            throw new RuntimeException(exceptionMsg);

        }

    }

    // ================ Helper methods

    private static boolean isJavaFile(Path p) {

        String fileName = p.getFileName().toString();

        int i = fileName.lastIndexOf('.');

        if ( (i < 0) || (i > fileName.length()) ) {

            return false;

        }

        return "java".equals(fileName.substring(i+1));

    }

    private static boolean findStringInFile(Path p, String searchTerm) throws IOException {

        long c = 0;

        try (Stream<String> stream = Files.lines(p)) {

            c = stream

                .filter(line -> line.contains(searchTerm))

                .count();

        }

        return (c != 0);

    }

    private static void printSetDiff(Set<String> a, Set<String> b,

        String setAName, String setBName) {

        if (a.size() > b.size()) {

            a.removeAll(b);

            System.out.printf("Set %s has more elements than set %s:", setAName, setBName);

            System.out.println();

            printSet(a);

        } else {

            b.removeAll(a);

            System.out.printf("Set %s has more elements than set %s:", setBName, setAName);

            System.out.println();

            printSet(b);

        }

    }

    private static void printSet(Set<String> set) {

        for (String e : set) {

            System.out.println(e);

        }

    }

    private static void print(String s) {

        System.out.println(s);

    }

}