parameters.java

J2ee中java网络编程的网络游戏lottery

package bingo.shared;

import java.util.Properties;
import java.io.FileInputStream;
import java.io.FileOutputStream;

public abstract class Parameters {

    private boolean DEBUG = false;
    private String propertiesFilename;
    private String propertiesDescription;

    protected Properties properties = null;

    protected Parameters(String propertiesFilename, String propertiesDescription) {
	this.propertiesFilename = propertiesFilename;
	this.propertiesDescription = propertiesDescription;
    }

    abstract protected void setDefaults(Properties defaults) ;
    abstract protected void updatePropertiesFromSettings() ;
    abstract protected void updateSettingsFromProperties() ;

    protected void getParameters() {
        Properties defaults = new Properties();
        FileInputStream in = null;

	setDefaults(defaults);

        properties = new Properties(defaults);

	try {
	    String folder = System.getProperty("user.home");
	    String filesep = System.getProperty("file.separator");
            in = new FileInputStream(folder
				     + filesep
				     + propertiesFilename);
	    properties.load(in);

	} catch (java.io.FileNotFoundException e) {
	    in = null;
	    ErrorMessages.error("Can't find properties file. " +
				"Using defaults.");
	} catch (java.io.IOException e) {
	    ErrorMessages.error("Can't read properties file. " +
				"Using defaults.");
	} finally {
	    if (in != null) {
		try { in.close(); } catch (java.io.IOException e) { }
		in = null;
	    }
	}

	updateSettingsFromProperties();

    }

    protected void saveParameters() {

	updatePropertiesFromSettings();

	if (DEBUG) {
	    System.out.println("Just set properties: " + propertiesDescription);
	    System.out.println(toString());
	}

        FileOutputStream out = null;

	try {
	    String folder = System.getProperty("user.home");
	    String filesep = System.getProperty("file.separator");
            out = new FileOutputStream(folder 
				       + filesep
				       + propertiesFilename);
	    properties.save(out, propertiesDescription);
	} catch (java.io.IOException e) {
	    ErrorMessages.error("Can't save properties. " +
				"Oh well, it's not a big deal.");
	} finally {
	    if (out != null) {
		try { out.close(); } catch (java.io.IOException e) { }
		out = null;
	    }
	}
    }
}