IMG_EXTENSIONS = MIMETypesSupport.getSupportedProperties(FileNameUtils.class)
.keySet();
/**
* The extension separator character.
*
* @since Commons IO 1.4
*/
public static final char EXTENSION_SEPARATOR = '.';
/**
* The extension separator String.
*
* @since Commons IO 1.4
*/
public static final String EXTENSION_SEPARATOR_STR = (new Character(EXTENSION_SEPARATOR)).toString();
/**
* The Unix separator character.
*/
private static final char UNIX_SEPARATOR = '/';
/**
* The Windows separator character.
*/
private static final char WINDOWS_SEPARATOR = '\\';
/**
* Returns the index of the last directory separator character.
*
* This method will handle a file in either Unix or Windows format. The
* position of the last forward or backslash is returned.
*
* The output will be the same irrespective of the machine that the code is
* running on.
*
* @param filename
* the filename to find the last path separator in, null returns
* -1
* @return the index of the last separator character, or -1 if there is no
* such character
*/
public static int indexOfLastSeparator(String filename) {
if (filename == null) {
return -1;
}
int lastUnixPos = filename.lastIndexOf(UNIX_SEPARATOR);
int lastWindowsPos = filename.lastIndexOf(WINDOWS_SEPARATOR);
return Math.max(lastUnixPos, lastWindowsPos);
}
/**
* Returns the index of the last extension separator character, which is a
* dot.
*
* This method also checks that there is no directory separator after the
* last dot. To do this it uses {@link #indexOfLastSeparator(String)} which
* will handle a file in either Unix or Windows format.
*
* The output will be the same irrespective of the machine that the code is
* running on.
*
* @param filename
* the filename to find the last path separator in, null returns
* -1
* @return the index of the last separator character, or -1 if there is no
* such character
*/
public static int indexOfExtension(String filename) {
if (filename == null) {
return -1;
}
int extensionPos = filename.lastIndexOf(EXTENSION_SEPARATOR);
int lastSeparator = indexOfLastSeparator(filename);
return (lastSeparator > extensionPos ? -1 : extensionPos);
}
// -----------------------------------------------------------------------
/**
* Gets the name minus the path from a full filename.
*
* This method will handle a file in either Unix or Windows format. The text
* after the last forward or backslash is returned.
*
*
* a/b/c.txt --> c.txt
* a.txt --> a.txt
* a/b/c --> c
* a/b/c/ --> ""
*
*
* The output will be the same irrespective of the machine that the code is
* running on.
*
* @param filename
* the filename to query, null returns null
* @return the name of the file without the path, or an empty string if none
* exists
*/
public static String getName(String filename) {
if (filename == null) {
return null;
}
int index = indexOfLastSeparator(filename);
return filename.substring(index + 1);
}
/**
* Gets the base name, minus the full path and extension, from a full
* filename.
*
* This method will handle a file in either Unix or Windows format. The text
* after the last forward or backslash and before the last dot is returned.
*
*
* a/b/c.txt --> c
* a.txt --> a
* a/b/c --> c
* a/b/c/ --> ""
*
*
* The output will be the same irrespective of the machine that the code is
* running on.
*
* @param filename
* the filename to query, null returns null
* @return the name of the file without the path, or an empty string if none
* exists
*/
public static String getBaseName(String filename) {
return removeExtension(getName(filename));
}
/**
* Gets the extension of a filename.
*
* This method returns the textual part of the filename after the last dot.
* There must be no directory separator after the dot.
*
*
* foo.txt --> "txt"
* a/b/c.jpg --> "jpg"
* a/b.txt/c --> ""
* a/b/c --> ""
*
*
* The output will be the same irrespective of the machine that the code is
* running on.
*
* @param filename
* the filename to retrieve the extension of.
* @return the extension of the file or an empty string if none exists.
*/
public static String getExtension(String filename) {
if (filename == null) {
return null;
}
int index = indexOfExtension(filename);
if (index == -1) {
return "";
} else {
return filename.substring(index + 1);
}
}
// -----------------------------------------------------------------------
/**
* Removes the extension from a filename.
*
* This method returns the textual part of the filename before the last dot.
* There must be no directory separator after the dot.
*
*
* foo.txt --> foo
* a\b\c.jpg --> a\b\c
* a\b\c --> a\b\c
* a.b\c --> a.b\c
*
*
* The output will be the same irrespective of the machine that the code is
* running on.
*
* @param filename
* the filename to query, null returns null
* @return the filename minus the extension
*/
public static String removeExtension(String filename) {
if (filename == null) {
return null;
}
int index = indexOfExtension(filename);
if (index == -1) {
return filename;
} else {
return filename.substring(0, index);
}
}
// -----------------------------------------------------------------------
/**
* Checks whether the extension of the filename is that specified.
*
* This method obtains the extension as the textual part of the filename
* after the last dot. There must be no directory separator after the dot.
* The extension check is case-sensitive on all platforms.
*
* @param filename
* the filename to query, null returns false
* @param extension
* the extension to check for, null or empty checks for no
* extension
* @return true if the filename has the specified extension
*/
public static boolean isExtension(String filename, String extension) {
if (filename == null) {
return false;
}
if (extension == null || extension.length() == 0) {
return (indexOfExtension(filename) == -1);
}
String fileExt = getExtension(filename);
return fileExt.equals(extension);
}
/**
* Checks whether the extension of the filename is one of those specified.
*
* This method obtains the extension as the textual part of the filename
* after the last dot. There must be no directory separator after the dot.
* The extension check is case-sensitive on all platforms.
*
* @param filename
* the filename to query, null returns false
* @param extensions
* the extensions to check for, null checks for no extension
* @return true if the filename is one of the extensions
*/
public static boolean isExtension(String filename, String[] extensions) {
if (filename == null) {
return false;
}
if (extensions == null || extensions.length == 0) {
return (indexOfExtension(filename) == -1);
}
String fileExt = getExtension(filename);
for (String extension : extensions) {
if (fileExt.equals(extension)) {
return true;
}
}
return false;
}
/**
* Checks whether the extension of the filename is one of those specified.
*
* This method obtains the extension as the textual part of the filename
* after the last dot. There must be no directory separator after the dot.
* The extension check is case-sensitive on all platforms.
*
* @param filename
* the filename to query, null returns false
* @param extensions
* the extensions to check for, null checks for no extension
* @return true if the filename is one of the extensions
*/
public static boolean isExtension(String filename, Collection extensions) {
if (filename == null) {
return false;
}
if (extensions == null || extensions.isEmpty()) {
return (indexOfExtension(filename) == -1);
}
String fileExt = getExtension(filename);
for (Iterator it = extensions.iterator(); it.hasNext();) {
if (fileExt.equals(it.next())) {
return true;
}
}
return false;
}
/**
* Checks whether the extension of the filename is an image extension.
*
* This method obtains the extension as the textual part of the filename
* after the last dot. There must be no directory separator after the dot.
* The extension check is case-sensitive on all platforms.
*
* @param filename
* the filename to query, null returns false
* @return true if the filename is an image extension.
*/
public static boolean hasImageExtension(String filename) {
return isExtension(filename, IMG_EXTENSIONS);
}
}
