Module java.base
Package java.nio.file.spi

# Class FileTypeDetector

java.lang.Object
java.nio.file.spi.FileTypeDetector

public abstract class FileTypeDetector extends Object
A file type detector for probing a file to guess its file type.

A file type detector is a concrete implementation of this class, has a zero-argument constructor, and implements the abstract methods specified below.

The means by which a file type detector determines the file type is highly implementation specific. A simple implementation might examine the file extension (a convention used in some platforms) and map it to a file type. In other cases, the file type may be stored as a file attribute or the bytes in a file may be examined to guess its file type.

Since:
  1.7
See Also:
  - `Files.probeContentType(Path)`

## Constructor Summary

Constructors
Modifier
Constructor
Description
`protected`
`FileTypeDetector()`
Initializes a new instance of this class.

## Method Summary

Modifier and Type
Method
Description
`abstract String`
`probeContentType(Path path)`
Probes the given file to guess its content type.

### Methods declared in class java.lang.Object

`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

## Constructor Details

### FileTypeDetector

protected FileTypeDetector()
Initializes a new instance of this class.

Throws:
  `SecurityException` - If a security manager has been installed and it denies `RuntimePermission``("fileTypeDetector")`

## Method Details

### probeContentType

public abstract String probeContentType(Path path) throws IOException
Probes the given file to guess its content type.

The means by which this method determines the file type is highly implementation specific. It may simply examine the file name, it may use a file attribute, or it may examine bytes in the file.

The probe result is the string form of the value of a Multipurpose Internet Mail Extension (MIME) content type as defined by RFC 2045: Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies. The string must be parsable according to the grammar in the RFC 2045.

Parameters:
  `path` - the path to the file to probe
Returns:
  The content type or `null` if the file type is not recognized
Throws:
  `IOException` - An I/O error occurs
  `SecurityException` - If the implementation requires to access the file, and a security manager is installed, and it denies an unspecified permission required by a file system provider implementation. If the file reference is associated with the default file system provider then the `SecurityManager.checkRead(String)` method is invoked to check read access to the file.
External Specifications
  - RFC 2045: Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies
See Also:
  - `Files.probeContentType(java.nio.file.Path)`