ZlibCodecFactory Class — netty Architecture

Source Code

codec-compression/src/main/java/io/netty/handler/codec/compression/ZlibCodecFactory.java lines 26–205

public final class ZlibCodecFactory {
    private static final InternalLogger logger = InternalLoggerFactory.getInstance(ZlibCodecFactory.class);

    private static final int DEFAULT_JDK_WINDOW_SIZE = 15;
    private static final int DEFAULT_JDK_MEM_LEVEL = 8;

    private static final boolean noJdkZlibDecoder;
    private static final boolean noJdkZlibEncoder;

    private static final boolean JZLIB_AVAILABLE;

    static {
        noJdkZlibDecoder = SystemPropertyUtil.getBoolean("io.netty.noJdkZlibDecoder", false);
        logger.debug("-Dio.netty.noJdkZlibDecoder: {}", noJdkZlibDecoder);

        noJdkZlibEncoder = SystemPropertyUtil.getBoolean("io.netty.noJdkZlibEncoder", false);
        logger.debug("-Dio.netty.noJdkZlibEncoder: {}", noJdkZlibEncoder);

        boolean jzlibAvailable;
        try {
            Class.forName("com.jcraft.jzlib.JZlib", false,
                PlatformDependent.getClassLoader(ZlibCodecFactory.class));
            jzlibAvailable = true;
        } catch (ClassNotFoundException t) {
            jzlibAvailable = false;
            logger.debug(
                "JZlib not in the classpath; the only window bits supported value will be " +
                    DEFAULT_JDK_WINDOW_SIZE);
        }
        JZLIB_AVAILABLE = jzlibAvailable;
    }

    /**
     * Returns {@code true} if specify a custom window size and mem level is supported.
     */
    public static boolean isSupportingWindowSizeAndMemLevel() {
        return JZLIB_AVAILABLE;
    }

    public static ZlibEncoder newZlibEncoder(int compressionLevel) {
        if (noJdkZlibEncoder) {
            return new JZlibEncoder(compressionLevel);
        } else {
            return new JdkZlibEncoder(compressionLevel);
        }
    }

    public static ZlibEncoder newZlibEncoder(ZlibWrapper wrapper) {
        if (noJdkZlibEncoder) {
            return new JZlibEncoder(wrapper);
        } else {
            return new JdkZlibEncoder(wrapper);
        }
    }

    public static ZlibEncoder newZlibEncoder(ZlibWrapper wrapper, int compressionLevel) {
        if (noJdkZlibEncoder) {
            return new JZlibEncoder(wrapper, compressionLevel);
        } else {
            return new JdkZlibEncoder(wrapper, compressionLevel);
        }
    }

    public static ZlibEncoder newZlibEncoder(ZlibWrapper wrapper, int compressionLevel, int windowBits, int memLevel) {
        if (noJdkZlibEncoder ||
                windowBits != DEFAULT_JDK_WINDOW_SIZE || memLevel != DEFAULT_JDK_MEM_LEVEL) {
            return new JZlibEncoder(wrapper, compressionLevel, windowBits, memLevel);
        } else {
            return new JdkZlibEncoder(wrapper, compressionLevel);
        }
    }

    public static ZlibEncoder newZlibEncoder(byte[] dictionary) {
        if (noJdkZlibEncoder) {
            return new JZlibEncoder(dictionary);
        } else {
            return new JdkZlibEncoder(dictionary);
        }
    }

    public static ZlibEncoder newZlibEncoder(int compressionLevel, byte[] dictionary) {