commons-io 1.3.2 · org.apache.commons.io.filefilter

This package defines an interface (IOFileFilter) that combines both java.io.FileFilter and java.io.FilenameFilter. Besides that the package offers a series of ready-to-use implementations of the IOFileFilter interface including implementation that allow you to combine other such filters.

These filter can be used to list files or in java.awt.FileDialog, for example.

There are a number of 'primitive' filters:

DirectoryFilter	Only accept directories
PrefixFileFilter	Filter based on a prefix
SuffixFileFilter	Filter based on a suffix
NameFileFilter	Filter based on a filename
WildcardFileFilter	Filter based on wildcards
AgeFileFilter	Filter based on last modified time of file
SizeFileFilter	Filter based on file size

And there are five 'boolean' filters:

TrueFileFilter	Accept all files
FalseFileFilter	Accept no files
NotFileFilter	Applies a logical NOT to an existing filter
AndFileFilter	Combines two filters using a logical AND
OrFileFilter	Combines two filter using a logical OR

These boolean FilenameFilters can be nested, to allow arbitrary expressions. For example, here is how one could print all non-directory files in the current directory, starting with "A", and ending in ".java" or ".class":

  File dir = new File(".");
  String[] files = dir.list( 
    new AndFileFilter(
      new AndFileFilter(
        new PrefixFileFilter("A"),
        new OrFileFilter(
          new SuffixFileFilter(".class"),
          new SuffixFileFilter(".java")
        )
      ),
      new NotFileFilter(
        new DirectoryFileFilter()
      )
    )
  );
  for ( int i=0; i<files.length; i++ ) {
    System.out.println(files[i]);
  }

This package also contains a utility class: FileFilterUtils. It allows you to use all file filters without having to put them in the import section. Here's how the above example will look using FileFilterUtils:

  File dir = new File(".");
  String[] files = dir.list( 
    FileFilterUtils.andFileFilter(
      FileFilterUtils.andFileFilter(
        FileFilterUtils.prefixFileFilter("A"),
        FileFilterUtils.orFileFilter(
          FileFilterUtils.suffixFileFilter(".class"),
          FileFilterUtils.suffixFileFilter(".java")
        )
      ),
      FileFilterUtils.notFileFilter(
        FileFilterUtils.directoryFileFilter()
      )
    )
  );
  for ( int i=0; i<files.length; i++ ) {
    System.out.println(files[i]);
  }

There are a few other goodies in that class so please have a look at the documentation in detail.

Modifier and Type	Interface and Description
public interface	ConditionalFileFilter Defines operations for conditional file filters.
public interface	IOFileFilter An interface which brings the FileFilter and FilenameFilter interfaces together.

Class Summary

Modifier and Type	Class and Description
public abstract class	AbstractFileFilter An abstract class which implements the Java FileFilter and FilenameFilter interfaces via the IOFileFilter interface.
public class	AgeFileFilter Filters files based on a cutoff time, can filter either newer files or files equal to or older.
public class	AndFileFilter A `java.io.FileFilter` providing conditional AND logic across a list of file filters.
public class	CanReadFileFilter This filter accepts `File`s that can be read.
public class	CanWriteFileFilter This filter accepts `File`s that can be written to.
public class	DelegateFileFilter This class turns a Java FileFilter or FilenameFilter into an IO FileFilter.
public class	DirectoryFileFilter This filter accepts `File`s that are directories.
public class	EmptyFileFilter This filter accepts files or directories that are empty.
public class	FalseFileFilter A file filter that always returns false.
public class	FileFileFilter This filter accepts `File`s that are files (not directories).
public class	FileFilterUtils Useful utilities for working with file filters.
public class	HiddenFileFilter This filter accepts `File`s that are hidden.
public class	NameFileFilter Filters filenames for a certain name.
public class	NotFileFilter This filter produces a logical NOT of the filters specified.
public class	OrFileFilter A `java.io.FileFilter` providing conditional OR logic across a list of file filters.
public class	PrefixFileFilter Filters filenames for a certain prefix.
public class	SizeFileFilter Filters files based on size, can filter either smaller files or files equal to or larger than a given threshold.
public class	SuffixFileFilter Filters files based on the suffix (what the filename ends with).
public class	TrueFileFilter A file filter that always returns true.
public class	WildcardFileFilter Filters files using the supplied wildcards.
public class	WildcardFilter Deprecated Use WilcardFileFilter. Deprecated as this class performs directory filtering which it shouldn't do, but that can't be removed due to compatability. Filters files using the supplied wildcards.

Package org.apache.commons.io.filefilter

Interface Summary

Class Summary