org/sonews/daemon/BootstrapConfig.java
author chris <chris@marvin>
Fri, 26 Jun 2009 16:48:50 +0200
changeset 1 6fceb66e1ad7
permissions -rw-r--r--
Hooray... sonews/0.5.0 final

HG: Enter commit message. Lines beginning with 'HG:' are removed.
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/*
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 *   SONEWS News Server
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 *   see AUTHORS for the list of contributors
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 *
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 *   This program is free software: you can redistribute it and/or modify
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 *   it under the terms of the GNU General Public License as published by
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 *   the Free Software Foundation, either version 3 of the License, or
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 *   (at your option) any later version.
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 *
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 *   This program is distributed in the hope that it will be useful,
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 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
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 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 *   GNU General Public License for more details.
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 *
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 *   You should have received a copy of the GNU General Public License
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 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
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 */
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package org.sonews.daemon;
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import java.io.FileInputStream;
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import java.io.FileNotFoundException;
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import java.io.FileOutputStream;
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import java.io.IOException;
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import java.util.Properties;
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import org.sonews.util.AbstractConfig;
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/**
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 * Manages the bootstrap configuration. It MUST contain all config values
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 * that are needed to establish a database connection.
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 * For further configuration values use the Config class instead as that class
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 * stores its values within the database.
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 * @author Christian Lins
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 * @since sonews/0.5.0
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 */
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public final class BootstrapConfig extends AbstractConfig
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{
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  /** Key constant. If value is "true" every I/O is written to logfile 
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   * (which is a lot!) 
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   */
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  public static final String DEBUG              = "sonews.debug";
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  /** Key constant. Value is classname of the JDBC driver */
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  public static final String STORAGE_DBMSDRIVER = "sonews.storage.dbmsdriver";
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  /** Key constant. Value is JDBC connect String to the database. */
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  public static final String STORAGE_DATABASE   = "sonews.storage.database";
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  /** Key constant. Value is the username for the DBMS. */
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  public static final String STORAGE_USER       = "sonews.storage.user";
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  /** Key constant. Value is the password for the DBMS. */
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  public static final String STORAGE_PASSWORD   = "sonews.storage.password";
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  /** Key constant. Value is the name of the host which is allowed to use the
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   *  XDAEMON command; default: "localhost" */
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  public static final String XDAEMON_HOST       = "sonews.xdaemon.host";
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  /** The config key for the filename of the logfile */
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  public static final String LOGFILE = "sonews.log";
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  /** The filename of the config file that is loaded on startup */
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  public static volatile String FILE               = "sonews.conf";
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  private static final Properties defaultConfig = new Properties();
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  private static BootstrapConfig instance = null;
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  static
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  {
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    // Set some default values
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    defaultConfig.setProperty(STORAGE_DATABASE, "jdbc:mysql://localhost/sonews");
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    defaultConfig.setProperty(STORAGE_DBMSDRIVER, "com.mysql.jdbc.Driver");
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    defaultConfig.setProperty(STORAGE_USER, "sonews_user");
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    defaultConfig.setProperty(STORAGE_PASSWORD, "mysecret");
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    defaultConfig.setProperty(DEBUG, "false");
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  }
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  /**
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   * Note: this method is not thread-safe
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   * @return A Config instance
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   */
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  public static synchronized BootstrapConfig getInstance()
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  {
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    if(instance == null)
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    {
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      instance = new BootstrapConfig();
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    }
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    return instance;
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  }
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  // Every config instance is initialized with the default values.
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  private final Properties settings = (Properties)defaultConfig.clone();
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  /**
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   * Config is a singelton class with only one instance at time.
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   * So the constructor is private to prevent the creation of more
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   * then one Config instance.
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   * @see Config.getInstance() to retrieve an instance of Config
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   */
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  private BootstrapConfig()
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  {
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    try
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    {
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      // Load settings from file
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      load();
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    }
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    catch(IOException ex)
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    {
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      ex.printStackTrace();
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    }
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  }
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  /**
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   * Loads the configuration from the config file. By default this is done
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   * by the (private) constructor but it can be useful to reload the config
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   * by invoking this method.
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   * @throws IOException
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   */
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  public void load() 
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    throws IOException
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  {
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    FileInputStream in = null;
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    try
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    {
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      in = new FileInputStream(FILE);
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      settings.load(in);
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    }
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    catch (FileNotFoundException e)
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    {
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      // MUST NOT use Log otherwise endless loop
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      System.err.println(e.getMessage());
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      save();
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    }
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    finally
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    {
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      if(in != null)
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        in.close();
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    }
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  }
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  /**
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   * Saves this Config to the config file. By default this is done
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   * at program end.
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   * @throws FileNotFoundException
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   * @throws IOException
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   */
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  public void save() throws FileNotFoundException, IOException
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  {
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    FileOutputStream out = null;
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    try
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    {
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      out = new FileOutputStream(FILE);
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      settings.store(out, "SONEWS Config File");
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      out.flush();
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    }
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    catch(IOException ex)
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    {
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      throw ex;
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    }
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    finally
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    {
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      if(out != null)
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        out.close();
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    }
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  }
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  /**
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   * Returns the value that is stored within this config
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   * identified by the given key. If the key cannot be found
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   * the default value is returned.
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   * @param key Key to identify the value.
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   * @param def The default value that is returned if the key
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   * is not found in this Config.
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   * @return
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   */
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  public String get(String key, String def)
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  {
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    return settings.getProperty(key, def);
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  }
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  /**
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   * Sets the value for a given key.
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   * @param key
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   * @param value
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   */
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  public void set(final String key, final String value)
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  {
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    settings.setProperty(key, value);
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  }
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}