Hi Leo,
I think the problem is caused by negative value. java.util.Date and
java.sql.Timestamp handles differently on negative value. Following code
shows the difference:
public static void main(String[] args) {
Long l1 = Long.MIN_VALUE;
Long l2 = Long.MIN_VALUE -1;
Timestamp timestamp1 = new Timestamp(l1);
Timestamp timestamp2 = new Timestamp(l2);
Date date1 = new Date(l1);
Date date2 = new Date(l2);
System.out.println(timestamp1);
System.out.println(timestamp2);
System.out.println(date1);
System.out.println(date2);
}
The output of RI is:
292278994-08-17 15:12:55.192
292278994-08-17 15:12:55.807
Mon Dec 03 00:47:04 CST 292269055
Sun Aug 17 15:12:55 CST 292278994
Spec doesn't say how to handle negative value. (do i miss something here?)
How would you like to fix this problem?
On 10/27/06, Leo Li <[EMAIL PROTECTED]> wrote:
Hi, all:
When fixing jira 1703, I found that at an extreme situation,
TimeStamp.compareTo behaves differently from its semantic: the time it
represents:
Here is the example:
public static void main(String[] args) {
Long l1 = Long.MIN_VALUE;
Long l2 = Long.MIN_VALUE -1;
Timestamp timestamp1 = new Timestamp(l1);
Timestamp timestamp2 = new Timestamp(l2);
System.out.println(timestamp1);
System.out.println(timestamp2);
System.out.println(timestamp1.compareTo(timestamp2));
}
We get:
292278994-08-17 15:12:55.192
292278994-08-17 15:12:55.807
1
From the times the timestamps represent, timestamp1 than timestamp2,
which indicate that timestamp1.compareTo(timestamp2) should be -1, while
the
actual result is 1, which indicate the reversed time sequence.
Furthermore, as the spec says java.sql.Timestamp wraps the
java.util.Date:"A thin wrapper around java.util.Date that allows the JDBC
API to identify this as an SQL TIMESTAMP value. It adds the ability to
hold
the SQL TIMESTAMP nanos value and provides formatting and parsing
operations
to support the JDBC escape syntax for timestamp values".
I apply the same long value to java.util.Date:
Long l1 = Long.MIN_VALUE;
Long l2 = Long.MIN_VALUE -1;
Date date1 = new Date(l1);
Date date2 = new Date(l2);
System.out.println(date1.compareTo(date2));
I got -1, which indicate that date1 is earlier than date2 as we expected.
The samething happens on java.sql.Date.
If no one objects, I will regard it as RI's bug and go on with my patch.
--
Leo Li
China Software Development Lab, IBM
--
Best regards,
Andrew Zhang
