Description
Trys to change file's extension to extensionNew.
License
Open Source License
Parameter
| Parameter | Description |
|---|
| file | the currently existing file |
| extensionNew | the new extension for file; must not contain a '.' char in it |
Exception
| Parameter | Description |
|---|
| IllegalArgumentException | if file is Check#validFile not valid; extensionNew is blank or contains a '.' char |
| SecurityException | if a security manager exists and write access to file |
| IOException | if an I/O problem occurs; this includes failure of the file to be renamed |
Return
a new File instance that has extensionNew
Declaration
public static File changeExtension(File file, String extensionNew)
throws IllegalArgumentException, SecurityException, IOException
Method Source Code
/*//from www.j a v a 2s.c o m
Copyright ? 2008 Brent Boyer
This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the Lesser GNU General Public License for more details.
You should have received a copy of the Lesser GNU General Public License along with this program (see the license directory in this project). If not, see <http://www.gnu.org/licenses/>.
*/
import bb.science.FormatUtil;
import bb.util.Check;
import bb.util.StringUtil;
import bb.util.ThrowableUtil;
import bb.util.logging.LogUtil;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.util.Random;
import java.util.logging.Level;
import org.junit.Assert;
import org.junit.Test;
public class Main{
/**
* Trys to change file's extension to extensionNew.
* If file currently has an extension, it is replaced by extensionNew,
* and if file lacks an extension, extensionNew is appended to its name.
* The new file must not currently exist (to be safest, this method never overwrites).
* <p>
* @param file the currently existing file
* @param extensionNew the new extension for file; must not contain a '.' char in it
* @return a new File instance that has extensionNew
* @throws IllegalArgumentException if file is {@link Check#validFile not valid}; extensionNew is blank or contains a '.' char
* @throws SecurityException if a security manager exists and write access to file
* @throws IOException if an I/O problem occurs; this includes failure of the file to be renamed
*/
public static File changeExtension(File file, String extensionNew)
throws IllegalArgumentException, SecurityException, IOException {
Check.arg().validFile(file);
Check.arg().notBlank(extensionNew);
if (extensionNew.contains("."))
throw new IllegalArgumentException("extensionNew = "
+ extensionNew + " contains a '.' char");
File parent = file.getParentFile();
String nameNew = getNameMinusExtension(file) + "." + extensionNew;
File fileNew = new File(parent, nameNew);
return rename(file, fileNew);
}
/**
* Returns the file's name minus any extension, that is, the part of its name up to (but not including) the last '.' char.
* For example, if presented with a file named "helloWorld.old.txt" then "helloWorld.old" is returned.
* If no extension exists (either because there is nothing after the last '.' char or a '.' char never occurs)
* then the complete file name (up to but not including any final '.' char) is returned.
* Note that the File need not actually exist nor be a normal file.
* <p>
* @param file the File whose name is will be returned
* @throws IllegalArgumentException if file == null
*/
public static String getNameMinusExtension(File file)
throws IllegalArgumentException {
Check.arg().notNull(file);
String name = file.getName();
int indexPeriod = name.lastIndexOf('.');
if (indexPeriod == -1)
return name;
else
return name.substring(0, indexPeriod);
}
/**
* Trys to rename file1 to file2.
* Since file2 may be in a different directory and/or have a different name,
* this is really a combined move/rename method.
* <p>
* This method was written because {@link File#renameTo File.renameTo} unfortunately
* merely returns a boolean indicating the success of the operation, which forces the user to check.
* In contrast, this method corrects that defect and throws an Exception instead.
* <p>
* Furthermore, for maximum safety, this method will never overwrite an existing but different file.
* Therefore, it insists that file2 must not currently exist unless it is equal to file1.
* (One reason why the user may wish to supply file2 equal to file1 is if their
* operating system has case insensitive file names:
* perhaps they are simply trying to change file1's name to a standard case.)
* <p>
* Note: {@link DirUtil#rename DirUtil.rename} should be used to rename directories.
* <p>
* @param file1 the currently existing file
* @param file2 the file that is to be renamed to
* @return file2
* @throws IllegalArgumentException if file1 is {@link Check#validFile not valid};
* file2 == null; file2 already exists and is not equal to file1
* @throws SecurityException if a security manager exists and denies write access to file1 or file2
* @throws IOException if an I/O problem occurs; this includes failure of the file to be renamed
*/
public static File rename(File file1, File file2)
throws IllegalArgumentException, SecurityException, IOException {
Check.arg().validFile(file1);
Check.arg().notNull(file2);
if (file2.exists() && !file1.equals(file2))
throw new IllegalArgumentException("file2 = " + file2.getPath()
+ " already exists and is not equal to file1 = "
+ file1.getPath());
boolean renamed = file1.renameTo(file2);
if (!renamed)
throw new IOException("failed to rename file1 = "
+ file1.getPath() + " to file2 = " + file2.getPath());
return file2;
}
}
Related
- getExtension(File file)
- getExtension(File file)
- getExtension(File file, boolean useFirstPeriod, boolean includePeriod)
- getExtension(String file)