FileHasher

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
```
@FunctionalInterface
public interface FileHasher
```
A function to convert a Path to a hash code used to check if the file content is changed. This is called by DirectoryWatcher after checking that the path exists and is not a directory. Therefore this hasher can generally assume that those two things are true.
By default, this hasher may throw an IOException, which will be treated as a `null` hash by the watcher, meaning the associated event will be ignored. If you want to handle that exception you can catch/rethrow it.

Field Summary

Fields
Modifier and Type	Field	Description
`static FileHasher`	`DEFAULT_FILE_HASHER`	The default file hasher instance, which uses Murmur3.
`static FileHasher`	`LAST_MODIFIED_TIME`	A file hasher that returns the last modified time provided by the OS.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type Method Description

FileHash hash(java.nio.file.Path path)

- Field Detail
  - DEFAULT_FILE_HASHER
```
static final FileHasher DEFAULT_FILE_HASHER
```
    The default file hasher instance, which uses Murmur3.
  - LAST_MODIFIED_TIME
```
static final FileHasher LAST_MODIFIED_TIME
```
    A file hasher that returns the last modified time provided by the OS.
    This only works reliably on certain file systems and JDKs that support at least millisecond-level precision.
- Method Detail
  - hash
```
FileHash hash(java.nio.file.Path path)
       throws java.io.IOException
```
    Throws:
    
    java.io.IOException