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'''
Created on Nov 20, 2012
@author: steger
'''
from DataProcessing.DataReader import DataReader
from DataProcessing.DataHeader import DataHeader
from DataProcessing.DataSource import DataSource
from DataProcessing.Data import Data
from DataProcessing.DataError import SamplerError
class Sampler(DataSource):
'''
classdocs
'''
def __init__(self, datasource):
'''
Constructor
@param datasource: table of records to manipulate with
@type datasource: DataSource
'''
if not isinstance(datasource, DataSource):
raise SamplerError("Wrong type of datasource %s" % datasource)
DataSource.__init__(self, datasource)
self._reader = DataReader(datasource = datasource._data)
header = DataHeader("%sSample(%s)" % (self.name, self.source.name))
for c in self._reader.headercells():
header.addColumn(c)
self._data = Data(self.um, header)
@property
def header(self):
return self._data.header
def __len__(self):
self.process()
return len(self._data)
def __getitem__(self, k):
return self._data._rawrecords.__getitem__(k)
class Head(Sampler):
def __init__(self, datasource, head = 10):
'''
Constructor
@param datasource: table of records to manipulate with
@type datasource: DataSource
@param head: the top n records of the table
@type head: int
'''
Sampler.__init__(self, datasource)
self._head = head
@property
def name(self):
return "Head"
@property
def head(self):
return self._head
@head.setter
def head(self, head):
self._head = int(head)
self._data.clear()
self._reader.rewind()
def _process(self):
if self._reader.sourceCleared.isSet():
self._reader.sourceCleared.clear()
self._reader.rewind()
self._data.clear()
if len(self._data) == self.head:
return
for x in self._reader:
self._data._rawrecords.append(x)
if len(self._data) == self.head:
self._data._onexpand()
return
raise SamplerError("Not enough sample %d/%d" % (len(self._data), self.head))
class Tail(Sampler):
def __init__(self, datasource, tail = 10):
'''
Constructor
@param datasource: table of records to manipulate with
@type datasource: DataSource
@param tail: the last n records of the table
@type tail: int
'''
Sampler.__init__(self, datasource)
self._tail = tail
@property
def name(self):
return "Tail"
@property
def tail(self):
return self._tail
@tail.setter
def tail(self, tail):
self._tail = int(tail)
self._data.clear()
self._reader.rewind()
def _process(self):
clear = False
if self._reader.sourceCleared.isSet():
self._reader.sourceCleared.clear()
self._reader.rewind()
self._data.clear()
for x in self._reader:
if len(self._data) == self.tail:
self._data._rawrecords.pop(0)
clear = True
self._data._rawrecords.append(x)
if clear:
self._data._onclear()
if len(self._data) == self.tail:
self._data._onexpand()
else:
raise SamplerError("Not enough sample %d/%d" % (len(self._data), self.tail))
class Sorter(Sampler):
def __init__(self, datasource, keycell = None, ascending = True):
'''
Constructor
@param datasource: table of records to manipulate with
@type datasource: DataSource
@param keycell: the key column to use for sorting
@type keycell: CellRequest or None
@param ascending: indicate the sortin order
@type ascending: bool
'''
Sampler.__init__(self, datasource)
self._asc = ascending
self._key = 0
if keycell:
self.keycell = keycell
@property
def name(self):
return "Sort"
@property
def ascending(self):
return self._asc
@ascending.setter
def ascending(self, ascending):
if bool(ascending) != self._asc:
self._asc = bool(ascending)
self._data.clear()
self._reader.rewind()
@property
def key(self):
return self._key
@key.setter
def key(self, key):
self._key = int(key)
@property
def keycell(self):
raise SamplerError("don't read this property")
@keycell.setter
def keycell(self, cellrequest):
for idx, _ in self.source.header.getCell(cellrequest):
self._key = idx
break
def _process(self):
clear = False
if self._reader.sourceCleared.isSet():
self._reader.sourceCleared.clear()
clear = True
if self._reader.sourceExpanded.isSet():
self._reader.sourceExpanded.clear()
clear = True
if not clear:
return
self._reader.rewind()
self._data.clear()
self._data._rawrecords = sorted(self._reader.source._rawrecords, key=lambda r: r[self.key], reverse = not self.ascending)
if len(self._data):
self._data._onclear()
self._data._onexpand()
else:
raise SamplerError("Not enough sample...")
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