Package org.apache.commons.io.comparator

Class ExtensionFileComparator

java.lang.Object

org.apache.commons.io.comparator.AbstractFileComparator

org.apache.commons.io.comparator.ExtensionFileComparator

All Implemented Interfaces:

java.io.Serializable, java.util.Comparator<java.io.File>

public class ExtensionFileComparator
extends AbstractFileComparator
implements java.io.Serializable

Compare the file name extensions for order (see FilenameUtils.getExtension(String)).

This comparator can be used to sort lists or arrays of files by their file extension either in a case-sensitive, case-insensitive or system dependant case sensitive way. A number of singleton instances are provided for the various case sensitivity options (using IOCase) and the reverse of those options.

Example of a case-sensitive file extension sort using the EXTENSION_COMPARATOR singleton instance:

       List<File> list = ...
       ExtensionFileComparator.EXTENSION_COMPARATOR.sort(list);
 

Example of a reverse case-insensitive file extension sort using the EXTENSION_INSENSITIVE_REVERSE singleton instance:

       File[] array = ...
       ExtensionFileComparator.EXTENSION_INSENSITIVE_REVERSE.sort(array);
 

Since:

1.4

Version:

$Id: ExtensionFileComparator.java 1304052 2012-03-22 20:55:29Z ggregory $

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private IOCase	caseSensitivity	Whether the comparison is case sensitive.
static java.util.Comparator<java.io.File>	EXTENSION_COMPARATOR	Case-sensitive extension comparator instance (see IOCase.SENSITIVE)
static java.util.Comparator<java.io.File>	EXTENSION_INSENSITIVE_COMPARATOR	Case-insensitive extension comparator instance (see IOCase.INSENSITIVE)
static java.util.Comparator<java.io.File>	EXTENSION_INSENSITIVE_REVERSE	Reverse case-insensitive extension comparator instance (see IOCase.INSENSITIVE)
static java.util.Comparator<java.io.File>	EXTENSION_REVERSE	Reverse case-sensitive extension comparator instance (see IOCase.SENSITIVE)
static java.util.Comparator<java.io.File>	EXTENSION_SYSTEM_COMPARATOR	System sensitive extension comparator instance (see IOCase.SYSTEM)
static java.util.Comparator<java.io.File>	EXTENSION_SYSTEM_REVERSE	Reverse system sensitive path comparator instance (see IOCase.SYSTEM)

Constructor Summary

Constructors

Constructor	Description
ExtensionFileComparator()	Construct a case sensitive file extension comparator instance.
ExtensionFileComparator(IOCase caseSensitivity)	Construct a file extension comparator instance with the specified case-sensitivity.

Method Summary

Modifier and Type	Method	Description
int	compare(java.io.File file1, java.io.File file2)	Compare the extensions of two files the specified case sensitivity.
java.lang.String	toString()	String representation of this file comparator.

Methods inherited from class org.apache.commons.io.comparator.AbstractFileComparator

sort, sort

Methods inherited from interface java.util.Comparator

equals, reversed, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Methods inherited from class java.lang.Object

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

Field Detail

EXTENSION_COMPARATOR

public static final java.util.Comparator<java.io.File> EXTENSION_COMPARATOR

Case-sensitive extension comparator instance (see IOCase.SENSITIVE)

EXTENSION_REVERSE

public static final java.util.Comparator<java.io.File> EXTENSION_REVERSE

Reverse case-sensitive extension comparator instance (see IOCase.SENSITIVE)

EXTENSION_INSENSITIVE_COMPARATOR

public static final java.util.Comparator<java.io.File> EXTENSION_INSENSITIVE_COMPARATOR

Case-insensitive extension comparator instance (see IOCase.INSENSITIVE)

EXTENSION_INSENSITIVE_REVERSE

public static final java.util.Comparator<java.io.File> EXTENSION_INSENSITIVE_REVERSE

Reverse case-insensitive extension comparator instance (see IOCase.INSENSITIVE)

EXTENSION_SYSTEM_COMPARATOR

public static final java.util.Comparator<java.io.File> EXTENSION_SYSTEM_COMPARATOR

System sensitive extension comparator instance (see IOCase.SYSTEM)

EXTENSION_SYSTEM_REVERSE

public static final java.util.Comparator<java.io.File> EXTENSION_SYSTEM_REVERSE

Reverse system sensitive path comparator instance (see IOCase.SYSTEM)

caseSensitivity

private final IOCase caseSensitivity

Whether the comparison is case sensitive.

Constructor Detail

ExtensionFileComparator

public ExtensionFileComparator()

Construct a case sensitive file extension comparator instance.

ExtensionFileComparator

public ExtensionFileComparator(IOCase caseSensitivity)

Construct a file extension comparator instance with the specified case-sensitivity.

Parameters:

caseSensitivity - how to handle case sensitivity, null means case-sensitive

Method Detail

compare

public int compare(java.io.File file1,
                   java.io.File file2)

Compare the extensions of two files the specified case sensitivity.

Specified by:

compare in interface java.util.Comparator<java.io.File>

Parameters:

file1 - The first file to compare

file2 - The second file to compare

Returns:

a negative value if the first file's extension is less than the second, zero if the extensions are the same and a positive value if the first files extension is greater than the second file.

toString

public java.lang.String toString()

String representation of this file comparator.

Overrides:

toString in class AbstractFileComparator

Returns:

String representation of this file comparator