org.springframework.integration.file

Class DefaultDirectoryScanner

java.lang.Object

org.springframework.integration.file.DefaultDirectoryScanner

All Implemented Interfaces:

DirectoryScanner

Direct Known Subclasses:

HeadDirectoryScanner, RecursiveLeafOnlyDirectoryScanner, WatchServiceDirectoryScanner

public class DefaultDirectoryScanner
extends Object
implements DirectoryScanner

Default directory scanner and base class for other directory scanners. Manages the default interrelations between filtering, scanning and locking.

Since:

2.0

Author:

Iwein Fuld, Gunnar Hillert

Constructor Summary

Constructors

Constructor and Description
DefaultDirectoryScanner() Initializes filter with a default list of FileListFilters using a CompositeFileListFilter: IgnoreHiddenFileListFilter AcceptOnceFileListFilter

Method Summary

Modifier and Type	Method and Description
protected File[]	listEligibleFiles(File directory) Subclasses may refine the listing strategy by overriding this method.
List<File>	listFiles(File directory) Scans the directory according to the strategy particular to this implementation and returns the selected files as a File array.
void	setFilter(FileListFilter<File> filter) Sets a custom filter to be used by this scanner.
void	setLocker(FileLocker locker) Sets a custom locker to be used by this scanner.
boolean	tryClaim(File file) Claim the file to process.

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultDirectoryScanner

public DefaultDirectoryScanner()

Initializes filter with a default list of FileListFilters using a CompositeFileListFilter:

• IgnoreHiddenFileListFilter
• AcceptOnceFileListFilter

Method Detail

setFilter

public void setFilter(FileListFilter<File> filter)

Description copied from interface: DirectoryScanner

Sets a custom filter to be used by this scanner. The filter will get a chance to reject files before the scanner presents them through its listFiles method. A scanner may use additional filtering that is out of the control of the provided filter.

Specified by:

setFilter in interface DirectoryScanner

Parameters:

filter - the custom filter to be used

setLocker

public final void setLocker(FileLocker locker)

Sets a custom locker to be used by this scanner. The locker will get a chance to lock files and reject claims on files that are already locked.

Specified by:

setLocker in interface DirectoryScanner

Parameters:

locker - the custom locker to be used

tryClaim

public final boolean tryClaim(File file)

Claim the file to process. It is up to the implementation to decide what additional safe guards are required to attain a claim to the file. But if a locker is set implementations MUST invoke its lock method and MUST return false if the locker did not grant the lock.

This class takes the minimal implementation and merely delegates to the locker if set.

Specified by:

tryClaim in interface DirectoryScanner

Parameters:

file - file to be claimed

Returns:

true if the claim was granted false otherwise

listFiles

public final List<File> listFiles(File directory)
                           throws IllegalArgumentException

Description copied from interface: DirectoryScanner

Scans the directory according to the strategy particular to this implementation and returns the selected files as a File array. This method may never return files that are rejected by the filter.

Specified by:

listFiles in interface DirectoryScanner

Parameters:

directory - the directory to scan for files

Returns:

a list of files representing the content of the directory

Throws:

IllegalArgumentException - if the input is incorrect

listEligibleFiles

protected File[] listEligibleFiles(File directory)

Subclasses may refine the listing strategy by overriding this method. The files returned here are passed onto the filter.

Parameters:

directory - root directory to use for listing

Returns:

the files this scanner should consider