Thanks for the feedback. The behavior described below is as designed, modulo the
problem with getCumPct, getCumFreq, which is a bug. Of course, given the feedback
(and pesky bugs that keep showing up ;-) it could be that the simplifying intention
in the design is doing more harm than good. The idea of converting all integral
values to Longs was so that addValue(1), addValue(new Long(1)), addValue(new
Integer(1)) would all have the same effect, enabling you to mix integral types when
adding values and querying counts and percentages. If we remove this, the
responsibility goes back to the user to add objects of only one type (and to create
the instances in the case of primitive values).
I can fix the cumXxx bug (for 1.0 final) if others agree that the interface should
stay as currently designed. In this case, I will also add a comment to the
valuesIterator() javadoc indicating that if the values that have been added are
integral, the Iterator returned contains Longs. The class javadoc mentions the
conversion now.
Does anyone feel strongly that the interface needs to change (i.e., eliminate the
integral conversions)? This was discussed once before, and I thought the conclusion
was that it should stay as is.
Phil
-----Original Message-----
From: Jon Langlois [mailto:[EMAIL PROTECTED]
Sent: Tue 9/14/2004 1:12 PM
To: [EMAIL PROTECTED]
Cc:
Subject: [math] Frequency handling of Integer values
In using org.apache.commons.math.stat.Frequency, I noticed that it does
a strange thing when given Integer values. The following test method
illustrates the problem:
public void testInteger() {
Frequency freq = new Frequency();
for (int i=0; i<10; i++) {
freq.addValue(new Integer(i));
}
assertTrue(freq.getCumFreq(new Integer(5)) == 5);
}
For some reason, the implementation of Frequency.addValue(Integer)
converts the value into a Long before storing it in the internal
TreeMap. Subsequent calls to getCount() and getPct() work okay, but
valuesIterator() returns an Iterator of Longs and
getCumPct()/getCumFreq() return 0 (because the internal Comparator is
throwing ClassCastExceptions).
If there isn't a reason to convert everything to Longs, the following
patch will fix the problem:
--- Frequency.java.orig 2004-09-14 12:46:06.945880000 -0400
+++ Frequency.java 2004-09-14 12:49:02.878859200 -0400
@@ -121,7 +121,7 @@
* @param v the value to add.
*/
public void addValue(Integer v) {
- addValue(new Long(v.longValue()));
+ addValue((Object) v);
}
/**
- Jon Langlois
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