An ISO 8583 message is composed of data elements. Time data elements are formatted as HHmmss (hours-minutes-seconds) strings. Date data elements are formatted as MMdd (month-day) strings. The current code base had a lot of duplicated code that used SimpleDateFormat instances to set the date/time data elements. To remove duplication (and avoid future duplication), we needed a helper method that would format date/time objects correctly and set the desired data element.
We didn't want to extend the ISO 8583 message (ISOMsg) class of jPOS. Instead, we created a helper class that wraps the ISOMsg class, and provides methods that we needed.
Again, we start with a test.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 | import static org.junit.Assert.*;import java.util.*;import org.junit.*;import org.jpos.iso.ISOException;import org.jpos.iso.ISOMsg;public class ISOMsgHelperTest { private ISOMsg isoMsg = new ISOMsg(); private ISOMsgHelper helper = new ISOMsgHelper(isoMsg); private Date dateTime = new GregorianCalendar(2011, Calendar.APRIL, 15, 9, 30, 59).getTime(); @Test public void setsIsoDateAsMonthDay() throws Exception { helper.setIsoDate(12, dateTime); assertEquals("0415", isoMsg.getString(12)); } @Test public void setsIsoTimeAsHourMinuteSecond() throws Exception { helper.setIsoDate(13, dateTime); assertEquals("093059", isoMsg.getString(13)); } @Test public void setsIsoDateTime() throws Exception { helper.setIsoDate(7, dateTime); assertEquals("0415093059", isoMsg.getString(7)); }} |
And here's the class that passes the test.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 | import java.util.Date;import java.text.*;import org.jpos.iso.ISOException;import org.jpos.iso.ISOMsg;public class ISOMsgHelper { private ISOMsg isoMsg; public ISOMsgHelper(ISOMsg isoMsg) { if (isoMsg == null) { throw new IllegalArgumentException("isoMsg cannot be null"); } this.isoMsg = isoMsg; } public void setIsoDate(int fldNo, Date date) throws ISOException { this.isoMsg.set(fldNo, dateFormat.get().format(date)); } public void setIsoTime(int fldNo, Date time) throws ISOException { this.isoMsg.set(fldNo, timeFormat.get().format(time)); } public void setIsoDateTime(int fldNo, Date dateTime) throws ISOException { this.isoMsg.set(fldNo, dateTimeFormat.get().format(dateTime)); } public Date getIsoDate(int fldNo) throws ISOException { if (this.isoMsg.hasField(fldNo)) { try { return dateFormat.get().parse(this.isoMsg.getString(fldNo)); } catch (ParseException e) { throw new ISOException("Error getting date field " + fldNo, e); } } return null; } // Other getters were removed to improve clarity // Need to make SimpleDateFormat objects thread-safe private static final ThreadLocal<SimpleDateFormat> dateFormat = new ThreadLocal<SimpleDateFormat>() { @Override protected SimpleDateFormat initialValue() { return new SimpleDateFormat("MMdd"); } }; private static final ThreadLocal<SimpleDateFormat> timeFormat = new ThreadLocal<SimpleDateFormat>() { @Override protected SimpleDateFormat initialValue() { return new SimpleDateFormat("HHmmss"); } }; private static final ThreadLocal<SimpleDateFormat> dateTimeFormat = new ThreadLocal<SimpleDateFormat>() { @Override protected SimpleDateFormat initialValue() { return new SimpleDateFormat("MMddHHmmss"); } };} |
Now, we can easily set date/time fields! And the date formatting objects are nicely encapsulated in one place.
1 2 3 4 5 6 7 8 | ISOMsg isoMsg = ...;ISOMsgHelper isoMsgHelper = new ISOMsgHelper(isoMsg);Date now = new Date();isoMsgHelper.setIsoDate(12, now); // local transaction dateisoMsgHelper.setIsoTime(13, now); // local transaction time...isoMsgHelper.setIsoDateTime(7, new Date()); // transmission date/time |
So far, it has removed a lot of duplicated code. We are expanding ISOMsgHelper to support other commonly used formats. Hope this helps!
