org.cryptomator.frontend.webdav.mount.WindowsDriveLetters.java Source code

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Here is the source code for org.cryptomator.frontend.webdav.mount.WindowsDriveLetters.java

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/*******************************************************************************
 * Copyright (c) 2016 Sebastian Stenzel and others.
 * This file is licensed under the terms of the MIT license.
 * See the LICENSE.txt file for more info.
 *
 * Contributors:
 *     Sebastian Stenzel - initial API and implementation
 *******************************************************************************/
package org.cryptomator.frontend.webdav.mount;

import static java.util.stream.Collectors.toSet;

import java.nio.file.FileSystems;
import java.nio.file.Path;
import java.util.Set;
import java.util.stream.IntStream;
import java.util.stream.StreamSupport;

import javax.inject.Inject;
import javax.inject.Singleton;

import org.apache.commons.lang3.CharUtils;
import org.apache.commons.lang3.SystemUtils;

import com.google.common.collect.Sets;

@Singleton
public final class WindowsDriveLetters {

    private static final Set<Character> A_TO_Z;

    static {
        try (IntStream stream = IntStream.rangeClosed('A', 'Z')) {
            A_TO_Z = stream.mapToObj(i -> (char) i).collect(toSet());
        }
    }

    @Inject
    public WindowsDriveLetters() {
    }

    public Set<Character> getOccupiedDriveLetters() {
        if (!SystemUtils.IS_OS_WINDOWS) {
            throw new UnsupportedOperationException("This method is only defined for Windows file systems");
        }
        Iterable<Path> rootDirs = FileSystems.getDefault().getRootDirectories();
        return StreamSupport.stream(rootDirs.spliterator(), false).map(Path::toString).map(CharUtils::toChar)
                .map(Character::toUpperCase).collect(toSet());
    }

    public Set<Character> getAvailableDriveLetters() {
        return Sets.difference(A_TO_Z, getOccupiedDriveLetters());
    }

}