Making a TimeStamp in Java

1
Making a TimeStamp in Java

• November 4, 2009
• TA Philip Matuskiewicz
• http//www.cse.buffalo.edu/pjm35/ta/116
• - HINT Take note of this address while it is up
  the following is almost a complete solution to
  Lab 7 and Im not giving this address out again
  this week!

2
Office Hours this Week - 11/4 11/6

• 12-2pm Today in Baldy 19
• Where Mike holds his office hours
• 3-4pm Today outside of NSC 225
• Friday from 3-4pm outside of NSC225
• I might show up unexpected at the baldy 19 lab
  Friday night at 8pm for a half hour or so.
• If I get an email requesting me to show up, I
  likely will

3
Extracting info from the lab description

• Invoke the calendar
• Calendar calendar new GregorianCalendar()
• Get the naming conventions
• Class Name Debug
• File Name Debug.java
• Containing Functions
• public static void dPrint( String printStr,
  boolean printToFile )
• Public static void main (String args)
• Time Stamp format
• Sun Nov 01 152122 EST 2009 anything

4
The Debug Class Framework

• import java.io.//for file writing
• import java.util.//for calendar stuff
• public class Debug
• public static void main(String args)
• dPrint("Any", true)//true will have Any
  written to a file
• public static void dPrint( String printStr,
  boolean printToFile )
• //Everything other than this method is complete
• //this is the only method you should need to
  modify to complete the lab

5
Useful Calendar Values

• calendar.get(Calendar.DAY_OF_WEEK) int value
  1-7 (1 being Sunday)
• calendar.get(Calendar.MONTH) int value 1-12, 1
  being January
• calendar.get(Calendar.DAY_OF_MONTH) int value
  1-31 (day)
• calendar.get(Calendar.HOUR_OF_DAY) int value
  1-24 (hour)
• calendar.get(Calendar.MINUTE) int value 1-60
  (minute)
• calendar.get(Calendar.SECOND) int value 1-60
  (minute)
• calendar.get(Calendar.DST_OFFSET) int value
  0-1 (0 being EST)
• NOTE double check this, I may be wrong that 1
  will be DST
• calendar.get(Calendar.YEAR) int (e.g. 2009)
• The timestamp we want should look like
• Sun Nov 01 152122 EST 2009 anything
• The above are in order, you just need to do some
  special stuff to a few of them and add spaces and
  s between them
• The d ones will need an array as explained in
  the next slide

6
Getting a day out of an int

• Create an array!
• String days "Sun" , "Mon", "Tue", "Wed" ,
  "Thu", "Fri", "Sat"
• String debugStatement dayscalendar.get(Calendar
  .DAY_OF_WEEK)-1"
• Do something similar on the other d values
• Also, new lines are allowed between the
  concatenate sign
• calendar.get(Calendar.DAY_OF_MONTH) " "
• calendar.get(Calendar.HOUR_OF_DAY)

7
Write the debug statement appropriately

• try
• //start a new file or erasse contents of
  existing file
• File f new File( "error.log" )
• FileWriter out new FileWriter( f )
• BufferedWriter writer new BufferedWriter( out
  )
• writer.write(errorStamp)
• writer.flush() //Hint This may be required to
  get the file written to
• catch (IOException e)
• System.err.println("Can't write to the file")