ResourceLeakDetector Class — netty Architecture

Source Code

common/src/main/java/io/netty/util/ResourceLeakDetector.java lines 42–739

public class ResourceLeakDetector<T> {

    private static final String PROP_LEVEL_OLD = "io.netty.leakDetectionLevel";
    private static final String PROP_LEVEL = "io.netty.leakDetection.level";
    private static final Level DEFAULT_LEVEL = Level.SIMPLE;

    private static final String PROP_TARGET_RECORDS = "io.netty.leakDetection.targetRecords";
    private static final int DEFAULT_TARGET_RECORDS = 4;

    private static final String PROP_SAMPLING_INTERVAL = "io.netty.leakDetection.samplingInterval";
    // There is a minor performance benefit in TLR if this is a power of 2.
    private static final int DEFAULT_SAMPLING_INTERVAL = 128;

    private static final String PROP_TRACK_CLOSE = "io.netty.leakDetection.trackClose";
    private static final boolean DEFAULT_TRACK_CLOSE = true;

    private static final int TARGET_RECORDS;
    static final int SAMPLING_INTERVAL;
    private static final boolean TRACK_CLOSE;

    /**
     * Represents the level of resource leak detection.
     */
    public enum Level {
        /**
         * Disables resource leak detection.
         */
        DISABLED,
        /**
         * Enables simplistic sampling resource leak detection which reports there is a leak or not,
         * at the cost of small overhead (default).
         */
        SIMPLE,
        /**
         * Enables advanced sampling resource leak detection which reports where the leaked object was accessed
         * recently at the cost of high overhead.
         */
        ADVANCED,
        /**
         * Enables paranoid resource leak detection which reports where the leaked object was accessed recently,
         * at the cost of the highest possible overhead (for testing purposes only).
         */
        PARANOID;

        /**
         * Returns level based on string value. Accepts also string that represents ordinal number of enum.
         *
         * @param levelStr - level string : DISABLED, SIMPLE, ADVANCED, PARANOID. Ignores case.
         * @return corresponding level or SIMPLE level in case of no match.
         */
        static Level parseLevel(String levelStr) {
            String trimmedLevelStr = levelStr.trim();
            for (Level l : values()) {
                if (trimmedLevelStr.equalsIgnoreCase(l.name()) || trimmedLevelStr.equals(String.valueOf(l.ordinal()))) {
                    return l;
                }
            }
            return DEFAULT_LEVEL;
        }
    }

    private static Level level;

    private static final InternalLogger logger = InternalLoggerFactory.getInstance(ResourceLeakDetector.class);

    static {
        final boolean disabled;
        if (SystemPropertyUtil.get("io.netty.noResourceLeakDetection") != null) {
            disabled = SystemPropertyUtil.getBoolean("io.netty.noResourceLeakDetection", false);
            logger.debug("-Dio.netty.noResourceLeakDetection: {}", disabled);
            logger.warn(
                    "-Dio.netty.noResourceLeakDetection is deprecated. Use '-D{}={}' instead.",
                    PROP_LEVEL, Level.DISABLED.name().toLowerCase());
        } else {
            disabled = false;
        }

        Level defaultLevel = disabled? Level.DISABLED : DEFAULT_LEVEL;

        // First read old property name
        String levelStr = SystemPropertyUtil.get(PROP_LEVEL_OLD, defaultLevel.name());