Mega Code Archive
A standalone program that deletes a specified file or directory
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/*
* Copyright (c) 2004 David Flanagan. All rights reserved.
* This code is from the book Java Examples in a Nutshell, 3nd Edition.
* It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied.
* You may study, use, and modify it for any non-commercial purpose,
* including teaching and use in open-source projects.
* You may distribute it non-commercially as long as you retain this notice.
* For a commercial use license, or to purchase the book,
* please visit http://www.davidflanagan.com/javaexamples3.
*/
import java.io.File;
/**
* This class is a static method delete() and a standalone program that deletes
* a specified file or directory.
*/
public class Delete {
/**
* This is the main() method of the standalone program. After checking it
* arguments, it invokes the Delete.delete() method to do the deletion
*/
public static void main(String[] args) {
if (args.length != 1) { // Check command-line arguments
System.err.println("Usage: java Delete <file or directory>");
System.exit(0);
}
// Call delete() and display any error messages it throws.
try {
delete(args[0]);
} catch (IllegalArgumentException e) {
System.err.println(e.getMessage());
}
}
/**
* The static method that does the deletion. Invoked by main(), and designed
* for use by other programs as well. It first makes sure that the specified
* file or directory is deleteable before attempting to delete it. If there is
* a problem, it throws an IllegalArgumentException.
*/
public static void delete(String filename) {
// Create a File object to represent the filename
File f = new File(filename);
// Make sure the file or directory exists and isn't write protected
if (!f.exists())
fail("Delete: no such file or directory: " + filename);
if (!f.canWrite())
fail("Delete: write protected: " + filename);
// If it is a directory, make sure it is empty
if (f.isDirectory()) {
String[] files = f.list();
if (files.length > 0)
fail("Delete: directory not empty: " + filename);
}
// If we passed all the tests, then attempt to delete it
boolean success = f.delete();
// And throw an exception if it didn't work for some (unknown) reason.
// For example, because of a bug with Java 1.1.1 on Linux,
// directory deletion always fails
if (!success)
fail("Delete: deletion failed");
}
/** A convenience method to throw an exception */
protected static void fail(String msg) throws IllegalArgumentException {
throw new IllegalArgumentException(msg);
}
}
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