Java Directory Delete on Exit cleanDirectoryOnExit(File directory)

Description

Cleans a directory without deleting net.

License

Open Source License

Parameter

Parameter	Description
directory	directory to clean, must not be <code>null</code>

Exception

Parameter	Description
NullPointerException	if the directory is <code>null</code>
IOException	in case cleaning is unsuccessful

Declaration

private static void cleanDirectoryOnExit(File directory) throws IOException 

Method Source Code

//package com.java2s;
//License from project: Open Source License 

import java.io.File;

import java.io.IOException;

public class Main {
    /**/*from w  w w.  j  a  va2  s  . c o  m*/
     * Cleans a directory without deleting net.
     * @param directory directory to clean, must not be <code>null</code>
     * @throws NullPointerException if the directory is <code>null</code>
     * @throws IOException in case cleaning is unsuccessful
     */
    private static void cleanDirectoryOnExit(File directory) throws IOException {
        if (!directory.exists()) {
            String message = directory + " does not exist";
            throw new IllegalArgumentException(message);
        }

        if (!directory.isDirectory()) {
            String message = directory + " is not a directory";
            throw new IllegalArgumentException(message);
        }

        File[] files = directory.listFiles();
        if (files == null) { // null if security restricted
            throw new IOException("Failed to list contents of " + directory);
        }

        IOException exception = null;
        for (File file : files) {
            try {
                forceDeleteOnExit(file);
            } catch (IOException ioe) {
                exception = ioe;
            }
        }

        if (null != exception) {
            throw exception;
        }
    }

    /**
     * Schedules a file to be deleted when JVM exits. If file is directory delete net
     * and all sub-directories.
     * @param file file or directory to delete, must not be <code>null</code>
     * @throws NullPointerException if the file is <code>null</code>
     * @throws IOException in case deletion is unsuccessful
     */
    public static void forceDeleteOnExit(File file) throws IOException {
        if (file.isDirectory()) {
            deleteDirectoryOnExit(file);
        } else {
            file.deleteOnExit();
        }
    }

    /**
     * Schedules a directory recursively for deletion on JVM exit.
     * @param directory directory to delete, must not be <code>null</code>
     * @throws NullPointerException if the directory is <code>null</code>
     * @throws IOException in case deletion is unsuccessful
     */
    private static void deleteDirectoryOnExit(File directory) throws IOException {
        if (!directory.exists()) {
            return;
        }

        if (!isSymlink(directory)) {
            cleanDirectoryOnExit(directory);
        }
        directory.deleteOnExit();
    }

    /**
     * Determines whether the specified file is a Symbolic Link rather than an
     * actual file.
     * <p>
     * Will not return true if there is a Symbolic Link anywhere in the path, only
     * if the specific file is.
     * @param file the file to check
     * @return true if the file is a Symbolic Link
     * @throws IOException if an IO error occurs while checking the file
     * @since Commons IO 2.0
     */
    public static boolean isSymlink(File file) throws IOException {
        if (file == null) {
            throw new NullPointerException("File must not be null");
        }

        /*
         * if (FilenameUtils.isSystemWindows()) { return false; }
         */

        File fileInCanonicalDir = null;
        if (file.getParent() == null) {
            fileInCanonicalDir = file;
        } else {
            File canonicalDir = file.getParentFile().getCanonicalFile();
            fileInCanonicalDir = new File(canonicalDir, file.getName());
        }

        if (fileInCanonicalDir.getCanonicalFile().equals(fileInCanonicalDir.getAbsoluteFile())) {
            return false;
        } else {
            return true;
        }
    }
}

Related

1. cleanDirectoryOnExit(File directory)