fileappendermanager.java

模拟退火是一种启发式算法

package org.theblueplanet.annealing;

import java.io.File;
import java.io.IOException;

import org.apache.log4j.Logger;
import org.apache.log4j.PatternLayout;
import org.apache.log4j.RollingFileAppender;

/**
 *  Handles output logging to file.
 *
 * @see org.apache.log4j.RollingFileAppender
 *
 * @author     Charles M間nin
 * @since    November 3, 2001
 * @version    1.0
 */
public class FileAppenderManager {
    private int currentState;
    private int desiredState;
    private Logger logger                     = Logger.getLogger("org.theblueplanet.annealing");
    private RollingFileAppender fileAppender = null;
    private File outputFile;
    private PatternLayout layout;
    /**
     *  Disable logging to file.
     */
    public final static int NO_APPEND         = 0;
    /**
     *  Enable logging to file and append to existing logging file.
     */
    public final static int APPEND            = 1;
    /**
     *  Enable logging to file and overwrite existing logging file.
     */
    public final static int OVERWRITE         = 2;
    /**
     *  Maximum file size after which log file is rolled over.
     */
    public final static long MAXFILESIZE      = 1000000L;
    /**
     *  Maximum number of log files.
     */
    public final static int MAXFILEINDEX      = 10;
    private final static String layoutString  = "%d{ABSOLUTE} %m%n";
    private final static String appenderName  = "FILE_APPENDER";

    /**
     *  Constructor for the FileAppenderManager object.
     */
    public FileAppenderManager() {
        this.layout = new PatternLayout(layoutString);
        this.currentState = NO_APPEND;
        outputFile = new File(System.getProperty("user.home"), "JSimul.log");
    }

    /**
     *  Sets the desiredState attribute of the FileAppenderManager object.
     *
     * @param  desiredState  The new desiredState value
     */
    public void setDesiredState(int desiredState) {
        this.desiredState = desiredState;
    }

    /**
     *  Gets the desiredState attribute of the FileAppenderManager object.
     *
     * @return    The desiredState value
     */
    public int getDesiredState() {
        return desiredState;
    }

    /**
     *  Handles the creation/update/disabling of the file appender.
     */
    public void updateFileAppender() {
        try {
            if (desiredState == NO_APPEND &&
                    (currentState == APPEND || currentState == OVERWRITE)) {
                logger.removeAppender(fileAppender);
            }
            if (currentState == NO_APPEND && desiredState == APPEND) {
                fileAppender = new RollingFileAppender(layout, outputFile.getAbsolutePath(), true);
                setupFileAppender(fileAppender);
            } else if (currentState == NO_APPEND && desiredState == OVERWRITE) {
                fileAppender = new RollingFileAppender(layout, outputFile.getAbsolutePath(), false);
                setupFileAppender(fileAppender);
            } else if (currentState == APPEND && desiredState == OVERWRITE) {
                ((RollingFileAppender) logger.getAppender(appenderName)).setAppend(false);
            } else if (currentState == OVERWRITE && desiredState == APPEND) {
                ((RollingFileAppender) logger.getAppender(appenderName)).setAppend(true);
            }
            currentState = desiredState;
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }
    }

    /**
     *  Initialize the RollingFileAAppender and adds it to the Logger
     *
     * @param  fileAppender  Description of Parameter
     */
    private void setupFileAppender(RollingFileAppender fileAppender) {
        fileAppender.setMaximumFileSize(MAXFILESIZE);
        fileAppender.setMaxBackupIndex(MAXFILEINDEX);
        fileAppender.setName(appenderName);
        logger.addAppender(fileAppender);
    }

}