- Add lottery and plain round robin cpu policies. I didn't test

them extensively, mind you. Closes task #14.
- Added documentation for each cpu policy
- Manage extra-exception into PythonCPUPolicy (when the .py
file doesn't contain a similarly named class)
- Update exception output in GuiBuilder to make it slightly
more descriptive


git-svn-id: svn://svn.gna.org/svn/sgpemv2/trunk@983 3ecf2c5c-341e-0410-92b4-d18e462d057c

plugins/pyloader/src/builtin-policies/rr.py

@@ -0,0 +1,50 @@
+# src/builtin-policies/rr_priority.py - Copyright 2005, 2006, University
+#                            of Padova, dept. of Pure and Applied
+#                            Mathematics
+#
+# This file is part of SGPEMv2.
+#
+# This is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# SGPEMv2 is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with SGPEMv2; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+
+
+from CPUPolicy import CPUPolicy
+
+class rr(CPUPolicy) :
+    """Round Robin scheduling policy
+
+This policy executes a thread for a given amount
+of time (the time-slice value), and then puts it
+at the end of the queue. Does not pre-empt before
+the end of the time slice, since it doesn't take
+priority in account. Use rr_priority for that."""
+
+    def __init__(self):
+        pass;
+
+    def configure(self):
+        param = self.get_parameters()
+        param.register_int("Time slice", 1, 10000, True, 2)
+
+    def is_preemptive(self):
+        return False
+
+    def get_time_slice(self):
+        return self.get_parameters().get_int("Time slice")
+
+    def sort_queue(self, queue):
+        by_ltime = lambda a, b: \
+            a.get_last_acquisition() > \
+            b.get_last_acquisition()
+        self.sort(queue,by_ltime)