Added implementations of __gt__, __le__, etc. to DateTime. With these,

sorting a list of 30000 DateTimes is *eighteen times faster* when used
with Python 2.1 and 2.2.  (But this may actually just restore the former
performace of DateTime on Python 1.5.2.)  Also added tests.  This should
help ZCatalog.

lib/python/DateTime/DateTime.py

@@ -12,7 +12,7 @@
 ##############################################################################
 """Encapsulation of date/time values"""
 
-__version__='$Revision: 1.71 $'[11:-2]
+__version__='$Revision: 1.72 $'[11:-2]
 
 
 import re,sys, os, math,  DateTimeZone
@@ -1133,6 +1133,7 @@ class DateTime:
            the current object\'s day, in the object\'s timezone context"""
         return self.__class__(self._year,self._month,self._day,
                               23,59,59,self._tz)
+
     def greaterThan(self,t):
         """Compare this DateTime object to another DateTime object
            OR a floating point number such as that which is returned 
@@ -1142,8 +1143,15 @@ class DateTime:
            Revised to give more correct results through comparison of
            long integer milliseconds.
            """
-        try:    return (self.millis() > t.millis())
-        except: return (self._t > t)
+        # Optimized for sorting speed
+        try:
+            return (self._millis > t._millis)
+        except AttributeError:
+            try: self._millis
+            except AttributeError: self._upgrade_old()
+        return (self._t > t)
+
+    __gt__ = greaterThan
 
     def greaterThanEqualTo(self,t):
         """Compare this DateTime object to another DateTime object
@@ -1154,8 +1162,15 @@ class DateTime:
            Revised to give more correct results through comparison of
            long integer milliseconds.
            """           
-        try:    return (self.millis() >= t.millis())
-        except: return (self._t >= t)
+        # Optimized for sorting speed
+        try:
+            return (self._millis >= t._millis)
+        except AttributeError:
+            try: self._millis
+            except AttributeError: self._upgrade_old()
+        return (self._t >= t)
+
+    __ge__ = greaterThanEqualTo
 
     def equalTo(self,t):
         """Compare this DateTime object to another DateTime object
@@ -1166,8 +1181,15 @@ class DateTime:
            Revised to give more correct results through comparison of
            long integer milliseconds.
            """
-        try:    return (self.millis() == t.millis())
-        except: return (self._t == t)
+        # Optimized for sorting speed
+        try:
+            return (self._millis == t._millis)
+        except AttributeError:
+            try: self._millis
+            except AttributeError: self._upgrade_old()
+        return (self._t == t)
+
+    __eq__ = equalTo
 
     def notEqualTo(self,t):
         """Compare this DateTime object to another DateTime object
@@ -1178,8 +1200,15 @@ class DateTime:
            Revised to give more correct results through comparison of
            long integer milliseconds.
            """
-        try:    return (self.millis() != t.millis())
-        except: return (self._t != t)
+        # Optimized for sorting speed
+        try:
+            return (self._millis != t._millis)
+        except AttributeError:
+            try: self._millis
+            except AttributeError: self._upgrade_old()
+        return (self._t != t)
+
+    __ne__ = notEqualTo
 
     def lessThan(self,t):
         """Compare this DateTime object to another DateTime object
@@ -1190,8 +1219,15 @@ class DateTime:
            Revised to give more correct results through comparison of
            long integer milliseconds.
            """
-        try:    return (self.millis() < t.millis())
-        except: return (self._t < t)
+        # Optimized for sorting speed
+        try:
+            return (self._millis < t._millis)
+        except AttributeError:
+            try: self._millis
+            except AttributeError: self._upgrade_old()
+        return (self._t < t)
+
+    __lt__ = lessThan
 
     def lessThanEqualTo(self,t):
         """Compare this DateTime object to another DateTime object
@@ -1202,8 +1238,15 @@ class DateTime:
            Revised to give more correct results through comparison of
            long integer milliseconds.
            """
-        try:    return (self.millis() <= t.millis())
-        except: return (self._t <= t)
+        # Optimized for sorting speed
+        try:
+            return (self._millis <= t._millis)
+        except AttributeError:
+            try: self._millis
+            except AttributeError: self._upgrade_old()
+        return (self._t <= t)
+
+    __le__ = lessThanEqualTo
 
     def isLeapYear(self):
         """Return true if the current year (in the context of the object\'s
@@ -1314,11 +1357,15 @@ class DateTime:
 
     def millis(self):
         """Return the millisecond since the epoch in GMT."""
-        try: millis = self._millis
-        except:
-            # Upgrade a previously pickled DateTime object.
-            millis = long(math.floor(self._t * 1000.0))
-            self._millis = millis
+        try:
+            return self._millis
+        except AttributeError:
+            return self._upgrade_old()
+
+    def _upgrade_old(self):
+        """Upgrades a previously pickled DateTime object."""
+        millis = long(math.floor(self._t * 1000.0))
+        self._millis = millis
         return millis
 
     def strftime(self, format):
@@ -1514,8 +1561,13 @@ class DateTime:
            You should use the methods lessThan, greaterThan,
            lessThanEqualTo, greaterThanEqualTo, equalTo and
            notEqualTo to avoid potential problems later!!"""
-        try:                   return cmp(self.millis(), obj.millis())
-        except AttributeError: return cmp(self._t,obj)
+        # Optimized for sorting speed.
+        try:
+            return cmp(self._millis, obj._millis)
+        except AttributeError:
+            try: self._millis
+            except AttributeError: self._upgrade_old()
+        return cmp(self._t,obj)
 
     def __hash__(self):
         """Compute a hash value for a DateTime"""

lib/python/DateTime/tests/testDateTime.py

@@ -133,6 +133,38 @@ class DateTimeTests (unittest.TestCase):
         dt1 = DateTime('1997/3/9 1:45pm GMT+8')
         assert dt1 - dt == 1.0, (dt, dt1)
 
+    def testCompareMethods(self):
+        '''Compare two dates using several methods'''
+        dt = DateTime('1997/1/1')
+        dt1 = DateTime('1997/2/2')
+        self.failUnless(dt1.greaterThan(dt))
+        self.failUnless(dt1.greaterThanEqualTo(dt))
+        self.failUnless(dt.lessThan(dt1))
+        self.failUnless(dt.lessThanEqualTo(dt1))
+        self.failUnless(dt.notEqualTo(dt1))
+        self.failUnless(not dt.equalTo(dt1))
+
+    def testCompareOperations(self, dt=None, dt1=None):
+        """Compare two dates using several operations"""
+        if dt is None:
+            dt = DateTime('1997/1/1')
+        if dt1 is None:
+            dt1 = DateTime('1997/2/2')
+        self.failUnless(dt1 > dt)
+        self.failUnless(dt1 >= dt)
+        self.failUnless(dt < dt1)
+        self.failUnless(dt <= dt1)
+        self.failUnless(dt != dt1)
+        self.failUnless(not (dt == dt1))
+
+    def testUpgradeOldInstances(self):
+        """Compare dates that don't have the _millis attribute yet."""
+        dt = DateTime('1997/1/1')
+        dt1 = DateTime('1997/2/2')
+        del dt._millis
+        del dt1._millis
+        self.testCompareOperations(dt, dt1)
+
     def testTZ2(self):
         '''Time zone manipulation test 2'''
         dt = DateTime()