LZ4 and xxHash 1.3.0 · net.jpountz.lz4.LZ4Factory

Entry point for the LZ4 API.

This class has 3 instances

a native instance which is a JNI binding to the original LZ4 C implementation.
a safe Java instance which is a pure Java port of the original C library,
an unsafe Java instance which is a Java port using the unofficial sun.misc.Unsafe API.

Only the safe instance is guaranteed to work on your JVM, as a consequence it is advised to use the fastestInstance() or fastestJavaInstance() to pull a LZ4Factory instance.

All methods from this class are very costly, so you should get an instance once, and then reuse it whenever possible. This is typically done by storing a LZ4Factory instance in a static field.

Field Summary

Modifier and Type	Field and Description
private final LZ4Compressor	fastCompressor
private final LZ4FastDecompressor	fastDecompressor Deprecated as a consequence of `LZ4FastDecompressor` being deprecated.
private final LZ4Compressor	highCompressor
private final LZ4Compressor[]	highCompressors
private final String	impl
private static LZ4Factory	JAVA_SAFE_INSTANCE
private static LZ4Factory	JAVA_UNSAFE_INSTANCE
private static LZ4Factory	NATIVE_INSTANCE
private final LZ4SafeDecompressor	safeDecompressor Deprecated as a consequence of `LZ4SafeDecompressor` being deprecated.

Constructor Summary

Access	Constructor and Description
private	LZ4Factory(String impl)

Method Summary

Modifier and Type	Method and Description
private static <T> T	classInstance(String cls)
public LZ4Decompressor	decompressor() Deprecated use `fastDecompressor()` Return a `LZ4Decompressor` instance.
public LZ4Compressor	fastCompressor() Return a blazing fast `LZ4Compressor`.
public LZ4FastDecompressor	fastDecompressor() Deprecated as a consequence of `LZ4FastDecompressor` being deprecated. Return a `LZ4FastDecompressor` instance.
public static LZ4Factory	fastestInstance() Return the fastest available `LZ4Factory` instance.
public static LZ4Factory	fastestJavaInstance() Return the fastest available `LZ4Factory` instance which does not rely on JNI bindings.
public LZ4Compressor	highCompressor() Return a `LZ4Compressor` which requires more memory than `fastCompressor()` and is slower but compresses more efficiently.
public LZ4Compressor	highCompressor(int compressionLevel) Return a `LZ4Compressor` which requires more memory than `fastCompressor()` and is slower but compresses more efficiently.
private static LZ4Factory	instance(String impl)
public static void	main(String[] args) Prints the fastest instance.
public static synchronized LZ4Factory	nativeInstance() Return a `LZ4Factory` instance that returns compressors and decompressors that are native bindings to the original C library.
public LZ4SafeDecompressor	safeDecompressor() Deprecated as a consequence of `LZ4SafeDecompressor` being deprecated. Return a `LZ4SafeDecompressor` instance.
public static synchronized LZ4Factory	safeInstance() Return a `LZ4Factory` instance that returns compressors and decompressors that are written with Java's official API.
public String	toString() Overrides java.lang.Object.toString. Returns a string representation of the object.
public LZ4UnknownSizeDecompressor	unknownSizeDecompressor() Deprecated use `safeDecompressor()` Return a `LZ4UnknownSizeDecompressor` instance.
public static synchronized LZ4Factory	unsafeInstance() Return a `LZ4Factory` instance that returns compressors and decompressors that may use `sun.misc.Unsafe` to speed up compression and decompression.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll wait wait wait

Field Detail

fastCompressor	back to summary
private final LZ4Compressor fastCompressor

fastDecompressor	back to summary
private final LZ4FastDecompressor fastDecompressor Deprecated as a consequence of `LZ4FastDecompressor` being deprecated. See corresponding docs for further information.

highCompressor	back to summary
private final LZ4Compressor highCompressor

highCompressors	back to summary
private final LZ4Compressor[] highCompressors

impl	back to summary
private final String impl

JAVA_SAFE_INSTANCE	back to summary
private static LZ4Factory JAVA_SAFE_INSTANCE

JAVA_UNSAFE_INSTANCE	back to summary
private static LZ4Factory JAVA_UNSAFE_INSTANCE

NATIVE_INSTANCE	back to summary
private static LZ4Factory NATIVE_INSTANCE

safeDecompressor	back to summary
private final LZ4SafeDecompressor safeDecompressor Deprecated as a consequence of `LZ4SafeDecompressor` being deprecated. See corresponding docs for further information.

Constructor Detail

LZ4Factory	back to summary
private LZ4Factory(String impl) throws ClassNotFoundException, NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException, NoSuchMethodException, InstantiationException, InvocationTargetException

Method Detail

classInstance	back to summary
private static <T> T classInstance(String cls) throws NoSuchFieldException, SecurityException, ClassNotFoundException, IllegalArgumentException, IllegalAccessException Annotations @SuppressWarnings:unchecked

decompressor	back to summary
public LZ4Decompressor decompressor() Deprecated use `fastDecompressor()` Return a `LZ4Decompressor` instance.

fastCompressor	back to summary
public LZ4Compressor fastCompressor() Return a blazing fast `LZ4Compressor`.

fastDecompressor	back to summary
public LZ4FastDecompressor fastDecompressor() Deprecated as a consequence of `LZ4FastDecompressor` being deprecated. See corresponding docs for further information. Return a `LZ4FastDecompressor` instance.

fastestInstance back to summary

fastestInstance	back to summary
public static LZ4Factory fastestInstance() Return the fastest available `LZ4Factory` instance. If the class loader is the system class loader and if the `native instance` loads successfully, then the `native instance` is returned, otherwise the `fastest Java instance` is returned. Please read `javadocs of nativeInstance()` before using this method.

public static LZ4Factory fastestInstance()

Return the fastest available LZ4Factory instance. If the class loader is the system class loader and if the native instance loads successfully, then the native instance is returned, otherwise the fastest Java instance is returned.

Please read javadocs of nativeInstance() before using this method.

fastestJavaInstance	back to summary
public static LZ4Factory fastestJavaInstance() Return the fastest available `LZ4Factory` instance which does not rely on JNI bindings. It first tries to load the `unsafe instance`, and then the `safe Java instance` if the JVM doesn't have a working `sun.misc.Unsafe`.

highCompressor	back to summary
public LZ4Compressor highCompressor() Return a `LZ4Compressor` which requires more memory than `fastCompressor()` and is slower but compresses more efficiently.

highCompressor back to summary

highCompressor	back to summary
public LZ4Compressor highCompressor(int compressionLevel) Return a `LZ4Compressor` which requires more memory than `fastCompressor()` and is slower but compresses more efficiently. The compression level can be customized. For current implementations, the following is true about compression level: It should be in range [1, 17] A compression level higher than 17 would be treated as 17. A compression level lower than 1 would be treated as 9.

public LZ4Compressor highCompressor(int compressionLevel)

Return a LZ4Compressor which requires more memory than fastCompressor() and is slower but compresses more efficiently. The compression level can be customized.

For current implementations, the following is true about compression level:

It should be in range [1, 17]
A compression level higher than 17 would be treated as 17.
A compression level lower than 1 would be treated as 9.

instance	back to summary
private static LZ4Factory instance(String impl)

main	back to summary
public static void main(String[] args) Prints the fastest instance.

nativeInstance back to summary

nativeInstance	back to summary
public static synchronized LZ4Factory nativeInstance() Return a `LZ4Factory` instance that returns compressors and decompressors that are native bindings to the original C library. Please note that this instance has some traps you should be aware of: Upon loading this instance, files will be written to the temporary directory of the system. Although these files are supposed to be deleted when the JVM exits, they might remain on systems that don't support removal of files being used such as Windows. The instance can only be loaded once per JVM. This can be a problem if your application uses multiple class loaders (such as most servlet containers): this instance will only be available to the children of the class loader which has loaded it. As a consequence, it is advised to either not use this instance in webapps or to put this library in the lib directory of your servlet container so that it is loaded by the system class loader.

public static synchronized LZ4Factory nativeInstance()

Return a LZ4Factory instance that returns compressors and decompressors that are native bindings to the original C library.

Please note that this instance has some traps you should be aware of:

Upon loading this instance, files will be written to the temporary directory of the system. Although these files are supposed to be deleted when the JVM exits, they might remain on systems that don't support removal of files being used such as Windows.
The instance can only be loaded once per JVM. This can be a problem if your application uses multiple class loaders (such as most servlet containers): this instance will only be available to the children of the class loader which has loaded it. As a consequence, it is advised to either not use this instance in webapps or to put this library in the lib directory of your servlet container so that it is loaded by the system class loader.

safeDecompressor	back to summary
public LZ4SafeDecompressor safeDecompressor() Deprecated as a consequence of `LZ4SafeDecompressor` being deprecated. See corresponding docs for further information. Return a `LZ4SafeDecompressor` instance.

safeInstance	back to summary
public static synchronized LZ4Factory safeInstance() Return a `LZ4Factory` instance that returns compressors and decompressors that are written with Java's official API.

toString	back to summary
public String toString() Overrides java.lang.Object.toString. Doc from java.lang.Object.toString. Returns a string representation of the object. Returns:String a string representation of the object. Annotations @Override

toString

back to summary

public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object.

Returns:String

a string representation of the object.

Annotations

@Override

unknownSizeDecompressor	back to summary
public LZ4UnknownSizeDecompressor unknownSizeDecompressor() Deprecated use `safeDecompressor()` Return a `LZ4UnknownSizeDecompressor` instance.

unsafeInstance	back to summary
public static synchronized LZ4Factory unsafeInstance() Return a `LZ4Factory` instance that returns compressors and decompressors that may use `sun.misc.Unsafe` to speed up compression and decompression.

public final Class LZ4Factory

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail