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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(FileRef)

Constructor Summary

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

Method Summary

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

Methods inherited from class java.lang.Object

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

Constructor Detail

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 Detail

probeContentType

public abstract String probeContentType(FileRef file)
                                 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 examines 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:

file - 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.

See Also:

Files.probeContentType(java.nio.file.FileRef)