Re: Comparing dates from database

From:
Lew <noone@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Sat, 25 Sep 2010 08:17:32 -0400
Message-ID:
<i7kp5r$5ib$1@news.albasani.net>
ruds wrote:

Sorry. Here's my copy pasted code:

<% if((fdate.equals(null))&&(cdate.equals(null))){%>NA<%}


Too many parentheses, and why did you ignore my remark about readability?

'if((fdate.equals(null))' can never evaluate to 'true'. It will either be
'false' or throw an exception. If it throws an exception, it will cause the
application screen to do whatever it is that it did, which you did not describe.

else{ if((fdate.after(accdate)) || (cdate.after(accdate))){%> N<%}
else if((fdate.equals(null))||(cdate.after(accdate))){%> N<%}
else if((fdate.after(accdate))||(cdate.equals(null))){%> N<%}
else{%> Y<%}}%>

Here accdate,fdate& cdate are the java.sql.Date objects. If fdate or
accdate is not present it has null value. accdateis always present and
it is the one which should be compared against.


"If ... accdate is not present ... accdate is always present ... "?

If either 'fdate' or 'cdate' is ever 'null', your code will blow up with a
'NullPointerException'. You cannot dereference the pointer in
'fdate.equals(...)' when 'fdate == null'.

--
Lew

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