Package org.apache.commons.io.filefilter

This package defines an interface (IOFileFilter) that combines both FileFilter and FilenameFilter.

See: Description

Interface Summary

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

Class Summary

Class	Description
AbstractFileFilter	Abstracts the implementation of the FileFilter (IO), FilenameFilter (IO), PathFilter (NIO) interfaces via our own IOFileFilter interface.
AgeFileFilter	Filters files based on a cutoff time, can filter either newer files or files equal to or older.
AndFileFilter	A FileFilter providing conditional AND logic across a list of file filters.
CanExecuteFileFilter	This filter accepts Files that can be executed.
CanReadFileFilter	This filter accepts Files that can be read.
CanWriteFileFilter	This filter accepts Files that can be written to.
DelegateFileFilter	This class turns a Java FileFilter or FilenameFilter into an IO FileFilter.
DirectoryFileFilter	This filter accepts Files that are directories.
EmptyFileFilter	This filter accepts files or directories that are empty.
FalseFileFilter	A file filter that always returns false.
FileEqualsFileFilter	Accepts only an exact File object match.
FileFileFilter	This filter accepts Files that are files (not directories).
FileFilterUtils	Useful utilities for working with file filters.
HiddenFileFilter	This filter accepts Files that are hidden.
MagicNumberFileFilter	File filter for matching files containing a "magic number".
NameFileFilter	Filters file names for a certain name.
NotFileFilter	This filter produces a logical NOT of the filters specified.
OrFileFilter	A FileFilter providing conditional OR logic across a list of file filters.
PathEqualsFileFilter	Accepts only an exact Path object match.
PathVisitorFileFilter	A file filter backed by a path visitor.
PrefixFileFilter	Filters file names for a certain prefix.
RegexFileFilter	Filters files using supplied regular expression(s).
SizeFileFilter	Filters files based on size, can filter either smaller files or files equal to or larger than a given threshold.
SuffixFileFilter	Filters files based on the suffix (what the file name ends with).
SymbolicLinkFileFilter	This filter accepts Files that are symbolic links.
TrueFileFilter	A file filter that always returns true.
WildcardFileFilter	Filters files using the supplied wildcards.
WildcardFilter	Deprecated Use WildcardFileFilter.

Package org.apache.commons.io.filefilter Description

This package defines an interface (IOFileFilter) that combines both FileFilter and 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 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

Using Classic IO

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]);
  }

You can alternatively build a filter tree using the "and", "or", and "not" methods on filters themselves:

  File dir = new File(".");
  String[] files = dir.list( 
    new AndFileFilter(
      new PrefixFileFilter("A").and(
        new SuffixFileFilter(".class").or(new SuffixFileFilter(".java"))),
      new DirectoryFileFilter().not()
    )
  );
  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]);
  }

Using NIO

You can combine Java file tree walking by using java.nio.file.Files.walk() APIs with filters:

   final Path dir = Paths.get("");
   // We are interested in files older than one day
   final long cutoff = System.currentTimeMillis() - (24 * 60 * 60 * 1000);
   final AccumulatorPathVisitor visitor = AccumulatorPathVisitor.withLongCounters(new AgeFileFilter(cutoff));
   //
   // Walk one dir
   Files.walkFileTree(dir, Collections.emptySet(), 1, visitor);
   System.out.println(visitor.getPathCounters());
   System.out.println(visitor.getFileList());
   //
   visitor.getPathCounters().reset();
   //
   // Walk dir tree
   Files.walkFileTree(dir, visitor);
   System.out.println(visitor.getPathCounters());
   System.out.println(visitor.getDirList());
   System.out.println(visitor.getFileList());

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