XXHashFactory (lz4 / xxhash

java.lang.Object
- net.jpountz.xxhash.XXHashFactory

```
public final class XXHashFactory
extends Object
```
Entry point to get XXHash32 and StreamingXXHash32 instances.
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 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 XXHashFactory 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 XXHashFactory instance in a static field.

Method Summary

Methods
Modifier and Type	Method and Description
`static XXHashFactory`	`fastestInstance()` Returns the fastest available `XXHashFactory` instance.
`static XXHashFactory`	`fastestJavaInstance()` Returns the fastest available `XXHashFactory` instance which does not rely on JNI bindings.
`XXHash32`	`hash32()` Returns a `XXHash32` instance.
`XXHash64`	`hash64()` Returns a `XXHash64` instance.
`static void`	`main(String[] args)` Prints the fastest instance.
`static XXHashFactory`	`nativeInstance()` Returns a `XXHashFactory` that returns `XXHash32` instances that are native bindings to the original C API.
`StreamingXXHash32`	`newStreamingHash32(int seed)` Return a new `StreamingXXHash32` instance.
`StreamingXXHash64`	`newStreamingHash64(long seed)` Return a new `StreamingXXHash64` instance.
`static XXHashFactory`	`safeInstance()` Returns a `XXHashFactory` that returns `XXHash32` instances that are written with Java's official API.
`String`	`toString()`
`static XXHashFactory`	`unsafeInstance()` Returns a `XXHashFactory` that returns `XXHash32` instances that may use `Unsafe` to speed up hashing.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Method Detail
  - nativeInstance
```
public static XXHashFactory nativeInstance()
```
    Returns a XXHashFactory that returns XXHash32 instances that are native bindings to the original C API.
    Please note that this instance has some traps you should be aware of:
    1. 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.
    2. 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.
    Returns:
    a XXHashFactory that returns XXHash32 instances that are native bindings to the original C API.
  - safeInstance
```
public static XXHashFactory safeInstance()
```
    Returns a XXHashFactory that returns XXHash32 instances that are written with Java's official API.
    
    Returns:
    a XXHashFactory that returns XXHash32 instances that are written with Java's official API.
  - unsafeInstance
```
public static XXHashFactory unsafeInstance()
```
    Returns a XXHashFactory that returns XXHash32 instances that may use Unsafe to speed up hashing.
    
    Returns:
    a XXHashFactory that returns XXHash32 instances that may use Unsafe to speed up hashing.
  - fastestJavaInstance
```
public static XXHashFactory fastestJavaInstance()
```
    Returns the fastest available XXHashFactory 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 Unsafe.
    
    Returns:
    the fastest available XXHashFactory instance which does not rely on JNI bindings.
  - fastestInstance
```
public static XXHashFactory fastestInstance()
```
    Returns the fastest available XXHashFactory 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.
    
    Returns:
    the fastest available XXHashFactory instance.
  - hash32
```
public XXHash32 hash32()
```
    Returns a XXHash32 instance.
    
    Returns:
    a XXHash32 instance.
  - hash64
```
public XXHash64 hash64()
```
    Returns a XXHash64 instance.
    
    Returns:
    a XXHash64 instance.
  - newStreamingHash32
```
public StreamingXXHash32 newStreamingHash32(int seed)
```
    Return a new StreamingXXHash32 instance.
    
    Parameters:
    seed - the seed to use
    
    Returns:
    a StreamingXXHash32 instance
  - newStreamingHash64
```
public StreamingXXHash64 newStreamingHash64(long seed)
```
    Return a new StreamingXXHash64 instance.
    
    Parameters:
    seed - the seed to use
    
    Returns:
    a StreamingXXHash64 instance
  - main
```
public static void main(String[] args)
```
    Prints the fastest instance.
    
    Parameters:
    args - no argument required
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object

Class XXHashFactory

Method Summary

Methods inherited from class java.lang.Object

Method Detail

nativeInstance

safeInstance

unsafeInstance

fastestJavaInstance

fastestInstance

hash32

hash64

newStreamingHash32

newStreamingHash64

main

toString