/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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 GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package java.nio.file;

import java.io.IOException;

/**

 * Thrown when a file system operation fails on one or two files. This class is

 * the general class for file system exceptions.

 *

 * @since 1.7

 */

public class FileSystemException

    extends IOException

{

    static final long serialVersionUID = -3055425747967319812L;

    private final String file;

    private final String other;

    /**

     * Constructs an instance of this class. This constructor should be used

     * when an operation involving one file fails and there isn't any additional

     * information to explain the reason.

     *

     * @param   file

     *          a string identifying the file or {@code null} if not known.

     */

    public FileSystemException(String file) {

        super((String)null);

        this.file = file;

        this.other = null;

    }

    /**

     * Constructs an instance of this class. This constructor should be used

     * when an operation involving two files fails, or there is additional

     * information to explain the reason.

     *

     * @param   file

     *          a string identifying the file or {@code null} if not known.

     * @param   other

     *          a string identifying the other file or {@code null} if there

     *          isn't another file or if not known

     * @param   reason

     *          a reason message with additional information or {@code null}

     */

    public FileSystemException(String file, String other, String reason) {

        super(reason);

        this.file = file;

        this.other = other;

    }

    /**

     * Returns the file used to create this exception.

     *

     * @return  the file (can be {@code null})

     */

    public String getFile() {

        return file;

    }

    /**

     * Returns the other file used to create this exception.

     *

     * @return  the other file (can be {@code null})

     */

    public String getOtherFile() {

        return other;

    }

    /**

     * Returns the string explaining why the file system operation failed.

     *

     * @return  the string explaining why the file system operation failed

     */

    public String getReason() {

        return super.getMessage();

    }

    /**

     * Returns the detail message string.

     */

    @Override

    public String getMessage() {

        if (file == null && other == null)

            return getReason();

        StringBuilder sb = new StringBuilder();

        if (file != null)

            sb.append(file);

        if (other != null) {

            sb.append(" -> ");

            sb.append(other);

        }

        if (getReason() != null) {

            sb.append(": ");

            sb.append(getReason());

        }

        return sb.toString();

    }

}