Dave Jarvis' Repositories

/*
 * Copyright 2016 David Croft and White Magic Software, Ltd.
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  o Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 *  o Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package com.scrivenvar.preferences;

import java.io.File;
import java.nio.file.FileSystems;
import java.util.prefs.Preferences;
import java.util.prefs.PreferencesFactory;

import static com.scrivenvar.Constants.APP_TITLE;

/**
 * PreferencesFactory implementation that stores the preferences in a
 * user-defined file. Usage:
 * <pre>
 * System.setProperty( "java.util.prefs.PreferencesFactory",
 * FilePreferencesFactory.class.getName() );
 * </pre>
 * <p>
 * The file defaults to <code>$user.home/.scrivenvar</code>, but can be changed
 * using <code>-Dapplication.name=preferences</code> when running the
 * application, or by calling <code>System.setProperty</code> with the
 * "application.name" property.
 * </p>
 */
public class FilePreferencesFactory implements PreferencesFactory {

  private static File preferencesFile;
  private Preferences rootPreferences;

  @Override
  public Preferences systemRoot() {
    return userRoot();
  }

  @Override
  public synchronized Preferences userRoot() {
    if( rootPreferences == null ) {
      rootPreferences = new FilePreferences( null, "" );
    }

    return rootPreferences;
  }

  public synchronized static File getPreferencesFile() {
    if( preferencesFile == null ) {
      String prefsFile = getPreferencesFilename();

      preferencesFile = new File( prefsFile ).getAbsoluteFile();
    }

    return preferencesFile;
  }

  public static String getPreferencesFilename() {
    final String filename = System.getProperty( "application.name", APP_TITLE );
    return System.getProperty( "user.home" ) + getSeparator() + "." + filename;
  }

  public static String getSeparator() {
    return FileSystems.getDefault().getSeparator();
  }
}