SimpleLogFormatter.java

package org.eclipse.paho.client.mqttv3.logging;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.text.MessageFormat;
import java.util.Date;
import java.util.logging.Formatter;
import java.util.logging.LogRecord;

/**
 * SimpleLogFormatter prints a single line 
 * log record in human readable form.
 */
public class SimpleLogFormatter extends Formatter {
	
	final String ls = System.getProperty("line.separator");
    /**
     * Constructs a <code>SimpleFormatter</code> object.
     */
    public SimpleLogFormatter() {
        super();
    }

    /**
     * Format the logrecord as a single line with well defined columns.
     */
    public String format(LogRecord r) {
        StringBuffer sb = new StringBuffer();
        sb.append(r.getLevel().getName()+"\t");
        sb.append(MessageFormat.format("{0, date, yy-MM-dd} {0, time, kk:mm:ss.SSSS} ",
                new Object[] { new Date(r.getMillis()) })+"\t");
        String cnm = r.getSourceClassName();
        String cn="";
        if (cnm != null) {
	        int cnl = cnm.length();
	        if (cnl>20) {
	        	cn = r.getSourceClassName().substring(cnl-19);
	        } else {
	        	char sp[] = {' '};
	        	StringBuffer sb1= new StringBuffer().append(cnm);
	        	cn = sb1.append(sp,0, 1).toString();
	        }        
        }
        sb.append(cn+"\t").append(" ");
        sb.append(left(r.getSourceMethodName(),23,' ')+"\t");
        sb.append(r.getThreadID()+"\t"); 
        sb.append(formatMessage(r)).append(ls);
        if (null != r.getThrown()) {
            sb.append("Throwable occurred: "); 
            Throwable t = r.getThrown();
            PrintWriter pw = null;
            try {
                StringWriter sw = new StringWriter();
                pw = new PrintWriter(sw);
                t.printStackTrace(pw);
                sb.append(sw.toString());
            } finally {
                if (pw != null) {
                    try {
                        pw.close();
                    } catch (Exception e) {
                        // ignore
                    }
                }
            }
        }
        return sb.toString();
    }
    
	/**
	   * Left justify a string.
	   *
	   * @param s the string to justify
	   * @param width the field width to justify within
	   * @param fillChar the character to fill with
	   *
	   * @return the justified string.
	   */
	  public static String left(String s, int width, char fillChar) {
	    if (s.length() >= width) {
	      return s;
	    }
	    StringBuffer sb = new StringBuffer(width);
	    sb.append(s);
	    for (int i = width - s.length(); --i >= 0;) {
	      sb.append(fillChar);
	    }
	    return sb.toString();
	  }

}