envoy/src/main/java/envoy/client/Config.java

package envoy.client;

import java.io.File;
import java.util.Properties;

import envoy.exception.EnvoyException;

/**
 * Project: <strong>envoy-client</strong><br>
 * File: <strong>Config.java</strong><br>
 * Created: <strong>12 Oct 2019</strong><br>
 * 
 * @author Kai S. K. Engelbart
 * @since Envoy v0.1-alpha
 */
public class Config {

	private String	server;
	private int		port;
	private File	localDB;
	private int		syncTimeout;

	private static Config config;

	private Config() {}

	public static Config getInstance() {
		if (config == null) config = new Config();
		return config;
	}

	/**
	 * Defaults to the {@code client.properties} file for information.
	 * This file contains information about
	 * the server and port, as well as the path to the local
	 * database and the synchronization timeout
	 * 
	 * @throws EnvoyException if the {@code client.properties} file could not be
	 *                        loaded
	 * @since Envoy v0.1-alpha
	 */
	public void load() throws EnvoyException {
		ClassLoader loader = getClass().getClassLoader();
		try {
			Properties properties = new Properties();
			properties.load(loader.getResourceAsStream("client.properties"));
			if (properties.containsKey("server")) server = properties.getProperty("server");
			if (properties.containsKey("port")) port = Integer.parseInt(properties.getProperty("port"));
			localDB		= new File(properties.getProperty("localDB", ".\\localDB"));
			syncTimeout	= Integer.parseInt(properties.getProperty("syncTimeout", "1000"));
		} catch (Exception e) {
			throw new EnvoyException("Failed to load client.properties", e);
		}
	}

	/**
	 * Sets the server, port and localDB path via command line properties --server /
	 * -s, --port / -p and --localDB / -db.
	 * 
	 * @param args the command line arguments to parse
	 * @throws EnvoyException if the command line arguments contain an unknown token
	 * @since Envoy v0.1-alpha
	 */
	public void load(String[] args) throws EnvoyException {
		for (int i = 0; i < args.length; i++)
			switch (args[i]) {
				case "--server":
				case "-s":
					server = args[++i];
					break;
				case "--port":
				case "-p":
					port = Integer.parseInt(args[++i]);
					break;
				case "--localDB":
				case "-db":
					localDB = new File(args[++i]);
					break;
				default:
					throw new EnvoyException("Unknown token " + args[i] + " found");
			}
	}

	/**
	 * @return {@code true} if server, port and localDB directory are known.
	 * @since Envoy v0.1-alpha
	 */
	public boolean isInitialized() { return server != null && !server.isEmpty() && port > 0 && port < 65566 && localDB != null; }

	/**
	 * @return the host name of the Envoy server
	 * @since Envoy v0.1-alpha
	 */
	public String getServer() { return server; }

	/**
	 * Changes the default server host name.
	 * Exclusively intended for development purposes.
	 * 
	 * @param server the host name of the Envoy server
	 * @since Envoy v0.1-alpha
	 */
	public void setServer(String server) { this.server = server; }

	/**
	 * @return the port at which the Envoy server is located on the host
	 * @since Envoy v0.1-alpha
	 */
	public int getPort() { return port; }

	/**
	 * Changes the default port.
	 * Exclusively intended for development purposes.
	 * 
	 * @param port the port where an Envoy server is located
	 * @since Envoy v0.1-alpha
	 */
	public void setPort(int port) { this.port = port; }

	/**
	 * @return the local database specific to the client user
	 * @since Envoy v0.1-alpha
	 **/
	public File getLocalDB() { return localDB; }

	/**
	 * Changes the default local database.
	 * Exclusively intended for development purposes.
	 *
	 * @param localDB the file containing the local database
	 * @since Envoy v0.1-alpha
	 **/
	public void setLocalDB(File localDB) { this.localDB = localDB; }

	/**
	 * @return the current time (milliseconds) that is waited between Syncs
	 * @since Envoy v0.1-alpha
	 */
	public int getSyncTimeout() { return syncTimeout; }

	/**
	 * @param syncTimeout sets the time (milliseconds) during which Sync waits
	 * @since Envoy v0.1-alpha
	 */
	public void setSyncTimeout(int syncTimeout) { this.syncTimeout = syncTimeout; }

}