com.antelmann.io
Class ExtensionFileFilter

java.lang.Object
  javax.swing.filechooser.FileFilter
      com.antelmann.io.ExtensionFileFilter

All Implemented Interfaces:

Filter<File>, FileFilter, FilenameFilter

public class ExtensionFileFilter
extends FileFilter
implements FileFilter, FilenameFilter, Filter<File>

ExtensionFileFilter is a flexible multi-purpose FileFilter. ExtensionFileFilter implements java.io.FileFilter as well as extending javax.swing.filechooser.FileFilter, so it can be used for GUIs as well as for other more general purposes.

ExtensionFileFilter keeps a default type, which can be used when saving a file when no file type was given (in the case of using ExtensionFileFilter as a javax.swing.filechooser.FileFilter). If a ExtensionFileFilter is constructed with the argument null for the default type, all file types will be accepted regardless of any additional added types; pattern matching will still take place.

As for the pattern matching capabilities:
By default, no pattern matching takes place until you explicitly add include or exclude patterns. If any patterns are present (i.e. getIncludePattern() or getExcludePattern() return an array with more than zero elements), the file is loaded as a String into memory and is checked against the given patterns. Note, therefore, that include/exclude patterns should only be used for small/medium sized files; if a file is too big to fit into memory to perform the pattern search, accept() will return false.
If include and/or exclude patterns are set, a file is accepted by this MyFilter only if all include patterns are found AND all exclude patterns are not found in the file. If any patterns are set and - during pattern matching - an IOException is caught, the file will not be accepted.
Note that include and/or exclude patterns should only be used if all files that may run through the accept() method fit into memory.

Author:

Holger Antelmann

Field Summary

Fields inherited from interface com.antelmann.util.Filter

EXCLUDE_ALL_FILTER, INCLUDE_ALL_FILTER

Constructor Summary

ExtensionFileFilter()
provides a default filter for text files (*.txt)

ExtensionFileFilter(ExtensionFileFilter filter)

ExtensionFileFilter(String defaultExtensionType)

ExtensionFileFilter(String defaultType, String description)
calls ExtensionFileFilter(defaultType, description, true)

ExtensionFileFilter(String defaultType, String description, boolean acceptDirectories)
if the defaultType is null, all files are initially accepted

Method Summary

boolean	accept(File f) checks file type and include/exclude pattern if applicable.
boolean	accept(File dir, String name)
boolean	addExcludePattern(String pattern) adds a pattern to be excluded in a file to be accepted
boolean	addIncludePattern(String pattern) adds a pattern to be included in a file to be accepted
ExtensionFileFilter	addType(String... type) allows to add additional file types to be accepted by this filter.
boolean	getAcceptDirectories()
String[]	getAddedTypes() returns file types other than the default type if they were added through addType(String).
String	getDefaultType() returns the default type for this filter
String	getDescription()
String[]	getExcludePattern() returns all exclude patterns to be checked (empty array returned if none)
String[]	getIncludePattern() returns all include patterns to be checked (empty array returned if none)
void	removeAllPattern() removes all include and exclude patterns and ensures therefore that the accept() method doesn't have to load the content of a file
boolean	removeExcludePattern(String pattern) removes a pattern to be included in a file to be accepted
boolean	removeIncludePattern(String pattern) removes a pattern to be included in a file to be accepted
boolean	removeType(String type) removes previously added type.
void	setAcceptDirectories(boolean flag)
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

ExtensionFileFilter

public ExtensionFileFilter(ExtensionFileFilter filter)

ExtensionFileFilter

public ExtensionFileFilter()

provides a default filter for text files (*.txt)

ExtensionFileFilter

public ExtensionFileFilter(String defaultExtensionType)

ExtensionFileFilter

public ExtensionFileFilter(String defaultType,
                           String description)

calls ExtensionFileFilter(defaultType, description, true)

ExtensionFileFilter

public ExtensionFileFilter(String defaultType,
                           String description,
                           boolean acceptDirectories)

if the defaultType is null, all files are initially accepted

Parameters:

defaultType - a string specifying the default type (example: "txt"); the string will be converted to lowercase

description - a string with a description (example: "Text files (*.txt)")

acceptDirectories - if true, directories are accepted by this filter

Method Detail

setAcceptDirectories

public void setAcceptDirectories(boolean flag)

getAcceptDirectories

public boolean getAcceptDirectories()

addType

public ExtensionFileFilter addType(String... type)

allows to add additional file types to be accepted by this filter. Note that if the default type is null, added types have no effect as all file types are then accepted (unless restricted by patterns).

See Also:

getDefaultType()

removeType

public boolean removeType(String type)

removes previously added type. This doesn't ever affect the default type. Note that if the default type is null, added types have no effect as all file types are then accepted (unless restricted by patterns).

See Also:

getDefaultType()

getAddedTypes

public String[] getAddedTypes()

returns file types other than the default type if they were added through addType(String). Note that if the default type is null, added types have no effect as all file types are then accepted (unless restricted by patterns).

See Also:

getDefaultType()

addIncludePattern

public boolean addIncludePattern(String pattern)

adds a pattern to be included in a file to be accepted

addExcludePattern

public boolean addExcludePattern(String pattern)

adds a pattern to be excluded in a file to be accepted

removeIncludePattern

public boolean removeIncludePattern(String pattern)

removes a pattern to be included in a file to be accepted

removeExcludePattern

public boolean removeExcludePattern(String pattern)

removes a pattern to be included in a file to be accepted

getIncludePattern

public String[] getIncludePattern()

returns all include patterns to be checked (empty array returned if none)

getExcludePattern

public String[] getExcludePattern()

returns all exclude patterns to be checked (empty array returned if none)

removeAllPattern

public void removeAllPattern()

removes all include and exclude patterns and ensures therefore that the accept() method doesn't have to load the content of a file

accept

public boolean accept(File dir,
                      String name)

Specified by:

accept in interface FilenameFilter

accept

public boolean accept(File f)

checks file type and include/exclude pattern if applicable. Directories are always accepted.

Specified by:

accept in interface Filter<File>

Specified by:

accept in interface FileFilter

Specified by:

accept in class FileFilter

getDescription

public String getDescription()

Specified by:

getDescription in class FileFilter

getDefaultType

public String getDefaultType()

returns the default type for this filter

toString

public String toString()

Overrides:

toString in class Object