Source Code for Module mcbase.widgets.mctablemodelro

  1  # -*- coding: utf-8 -*- 
  2   
  3  ############################################################ 
  4  # mctablemodelro.py 
  5  # 
  6  # Implements a table model for retreiving tabular data 
  7  # from application server. 
  8  # 
  9  # (C) 2008 Likya Software 
 10  ############################################################ 
 11   
 12  import copy 
 13  from datetime import date 
 14  from decimal import Decimal 
 15   
 16  from PyQt4.Qt import * 
 17  from twisted.internet import reactor, defer 
 18   
 19  from mc import MC 
 20   
 21   
 22 -class MCTableModelRO(QAbstractTableModel): 
 23      ''' 
 24      Model for read only tables. 
 25      ''' 
 26 -    def __init__(self, parentObject, modelObject, taskPath, *args, **kw): 
 27          ''' 
 28          Initializes the model 
 29          ''' 
 30          QAbstractTableModel.__init__(self, parentObject) 
 31   
 32          # Save most of the init parameters 
 33          self._modelObject = modelObject 
 34          self._columnLabels = self.getColumnLabels() 
 35          self._columnNames = modelObject.__mapper__.columns.keys() 
 36          self._taskPath = taskPath 
 37          self._args = args 
 38          self._kw = kw 
 39   
 40          self.numRows = MC.MAX_RECORDS 
 41          self.numCols = 0 
 42          self.cacheRows = MC.RO_TABLE_CACHE_SIZE 
 43          # Start and end of current cache 
 44          self.start = self.end = 0 
 45          self._maxData = 0 
 46          # Cache for objects displayed in table 
 47          self.cache = None 
 48          # Stores cache indexes 
 49          self.cacheIndex = None 
 50          # We are initially not busy 
 51          self._busy = False 
 52          # Initilize cache 
 53          self.initCache() 
 54   
 55 -    def getColumnLabels(self): 
 56          ''' 
 57          Returns column labels according to current model object set to this 
 58          view model. 
 59          ''' 
 60          labels = [] 
 61   
 62          for column in self._modelObject.__mapper__.columns: 
 63              labels.append(column.info.get('label') or '') 
 64   
 65          return labels 
 66   
 67 -    def getColumnSizes(self): 
 68          ''' 
 69          Returns column sizes according to current model object set to this 
 70          view model. 
 71          ''' 
 72          sizes = [] 
 73   
 74          for column in self._modelObject.__mapper__.columns: 
 75              sizes.append(column.info.get('width') or 0) 
 76   
 77          return sizes 
 78   
 79 -    def setModelObjectProperties(self, modelObject): 
 80          # Column names for this object 
 81          pass 
 82   
 83 -    def parent(self): 
 84          ''' 
 85          Original QAbstractTableModel parent() method does something 
 86          different than QWidget.parent() method. We override it here 
 87          in order to make it work like the rest. 
 88          ''' 
 89          return QObject.parent(self) 
 90   
 91      @defer.inlineCallbacks 
 92 -    def getData(self, start, end): 
 93          ''' 
 94          Gets data from the server. Data indexes are defined by start and end 
 95          parameters. 
 96   
 97          @param start: Start index of the data to be fetched 
 98          @type  start: int 
 99          @param end:   End index of the data to be fetched 
100          @type  end:   int 
101          ''' 
102          kw = copy.deepcopy(self._kw) 
103          kw['start'] = start 
104          kw['end'] = end 
105   
106          result = yield self.parent().execute(self._taskPath, *self._args, **kw) 
107   
108          defer.returnValue(result) 
109   
110 -    def initCache(self): 
111          ''' 
112          Initializes the structures related with cache structure. 
113          ''' 
114          self.cache = [None] * self.cacheRows 
115          self.cacheIndex = [None] * self.cacheRows 
116   
117      @defer.inlineCallbacks 
118 -    def cacheMiss(self, row): 
119          ''' 
120          Called when a given row is not present in the cache. 
121   
122          @param row: The index of data that was not found in the cache. 
123          ''' 
124          # If we are already busy then do nothing. 
125          if self._busy: 
126              defer.returnValue(None) 
127   
128          self._busy = True 
129          self.initCache() 
130          self.start = row - self.cacheRows / 2 
131   
132          # If we are already at the start, we can not go back. 
133          if self.start < 0: 
134              self.start = 0 
135   
136          self.end = row + self.cacheRows / 2 
137   
138          try: 
139              result = yield self.getData(self.start, self.end) 
140              defer.returnValue(self.receivedData(result)) 
141          except Exception, e: 
142              print '*** Error in cacheMiss(): ', e 
143              self._busy = False 
144       
145 -    def receivedData(self, rows): 
146          ''' 
147          This method is called upon receiving data from server. 
148           
149          @param rows: List containing objects. 
150          @type  rows: list 
151          ''' 
152          self._busy = False 
153           
154          oldMaxData = self._maxData 
155   
156          if not rows: 
157              self._maxData = 0 
158   
159          else: 
160   
161              for i, currentObject in enumerate(rows): 
162                  self.cache[i] = currentObject 
163                  self.cacheIndex[i] = i + self.start 
164   
165              if i + self.start + 1 < self.end: 
166                  # If we reach here then we are end of data 
167                  self.numRows = i + self.start + 1 
168              else: 
169                  if self.numRows <= i + self.start + 1: 
170                      self.numRows = i + self.start + 2 
171   
172              self._maxData = self.numRows 
173           
174          if self._maxData > oldMaxData: 
175              self.beginInsertRows(QModelIndex(), oldMaxData, self._maxData) 
176              self.endInsertRows() 
177              self.emit(SIGNAL('rowCountChanged(int)'), self._maxData) 
178   
179          elif self._maxData < oldMaxData: 
180              self.beginRemoveRows(QModelIndex(), self._maxData, oldMaxData) 
181              self.endRemoveRows() 
182              self.emit(SIGNAL('rowCountChanged(int)'), self._maxData) 
183           
184      @MC.returnQVariant 
185 -    def headerData(self, section, orientation, role=Qt.DisplayRole): 
186          ''' 
187          Overriden headerData method that feeds the view with vertical and 
188          horizontal header information. 
189          ''' 
190          if role not in (Qt.DisplayRole, Qt.ToolTipRole, Qt.TextAlignmentRole): 
191              return None 
192           
193          if orientation == Qt.Horizontal: 
194              extra = '' 
195              return u"%s %s" % (self._columnLabels[section], extra) 
196   
197 -    def data(self, index, role=Qt.DisplayRole): 
198          ''' 
199          Overriden data method, called by QTableView to obtain data for the 
200          passed index. 
201   
202          @param index: Index of the data desired 
203          @type  index: QModelIndex 
204          ''' 
205          if not index.isValid(): 
206              return MC.EMPTY_QVARIANT 
207   
208          row = index.row() 
209          col = index.column() 
210   
211          if row not in self.cacheIndex: 
212   
213              if not self._busy: 
214                  self.cacheMiss(row) 
215   
216              return MC.EMPTY_QVARIANT 
217   
218          # Display role 
219          if role in (Qt.DisplayRole, Qt.ToolTipRole): 
220              rowObject = self.cache[row - self.start] 
221              value = getattr(rowObject, self._columnNames[col]) 
222   
223              # If the data type is python date, convert it to QDate 
224              if type(value) == date: 
225                  dt = getattr(rowObject, self._columnNames[col]) 
226                  return QVariant(QDate(dt.year, dt.month, dt.day)) 
227               
228              # Special case for numeric fields 
229              if type(value) == Decimal: 
230                  value = '%.2f' % value 
231   
232              return QVariant(value) 
233   
234          elif role == Qt.TextAlignmentRole: 
235              rowObject = self.cache[row - self.start] 
236              value = getattr(rowObject, self._columnNames[col]) 
237   
238              if type(value) == Decimal: 
239                  # Right align numeric fields 
240                  return Qt.AlignRight | Qt.AlignVCenter 
241              else: 
242                  return Qt.AlignLeft | Qt.AlignVCenter 
243   
244          return MC.EMPTY_QVARIANT 
245   
246 -    def isBusy(self): 
247          ''' 
248          Returns True if model is busy, False otherwise. 
249          ''' 
250          return self._busy 
251   
252 -    def hideKeyColumns(self): 
253          ''' 
254          Hides key columns. 
255          ''' 
256          if not self.headerLoaded: 
257              self.headerLoaded = True 
258              for i, headerItem in enumerate(self.header): 
259                  if headerItem[MC.SOURCE_HEADER_STATUS] in MC.TABLE_HIDDEN_COL_TYPES: 
260                      if not self.parent()._main.isColumnHidden(i): 
261                          self.parent().hideColumn(i) 
262   
263 -    def rowCount(self, parentModel=None): 
264          ''' 
265          Overriden rowCount method, returns the number of rows present in the model 
266          ''' 
267          return self._maxData 
268   
269 -    def columnCount(self, parentModel=None): 
270          ''' 
271          Returns the number of columns displayed in table, overriden 
272          Qt model method. 
273          ''' 
274          return len(self._columnLabels) 
275   
276 -    def selectedObject(self, row): 
277          return self.cache[row - self.start] 
278