Source code for pyface.data_view.data_models.row_table_data_model

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#
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# license included in LICENSE.txt and may be redistributed only under
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""" A row-oriented data model implementation.

This module provides a concrete implementation of a data model for the
case of non-hierarchical, row-oriented data.
"""
from collections.abc import Sequence

from traits.api import Instance, List, observe
from traits.observation.api import trait

from pyface.data_view.abstract_data_model import (
    AbstractDataModel, DataViewSetError
)
from pyface.data_view.index_manager import IntIndexManager
from pyface.data_view.data_models.data_accessors import AbstractDataAccessor


[docs]class RowTableDataModel(AbstractDataModel): """ A data model that presents a sequence of objects as rows. The data is expected to be a sequence of row objects, each object providing values for the columns via an AbstractDataAccessor subclass. Concrete implementations can be found in the data_accessors module that get data from attributes, indices of sequences, and keys of mappings, but for more complex situations, custom accessors can be defined. """ #: A sequence of objects to display as rows. data = Instance(Sequence, allow_none=False) #: An object which describes how to map data for the row headers. row_header_data = Instance(AbstractDataAccessor, allow_none=False) #: An object which describes how to map data for each column. column_data = List(Instance(AbstractDataAccessor, allow_none=False)) #: The index manager that helps convert toolkit indices to data view #: indices. index_manager = Instance(IntIndexManager, args=(), allow_none=False) # Data structure methods
[docs] def get_column_count(self): """ How many columns in the data view model. Returns ------- column_count : non-negative int The number of columns that the data view provides. """ return len(self.column_data)
[docs] def can_have_children(self, row): """ Whether or not a row can have child rows. Only the root has children. Parameters ---------- row : sequence of int The indices of the row as a sequence from root to leaf. Returns ------- can_have_children : bool Whether or not the row can ever have child rows. """ return len(row) == 0
[docs] def get_row_count(self, row): """ How many child rows the row currently has. Parameters ---------- row : sequence of int The indices of the row as a sequence from root to leaf. Returns ------- row_count : non-negative int The number of child rows that the row has. """ if len(row) == 0: return len(self.data) else: return 0
# Data value methods
[docs] def get_value(self, row, column): """ Return the Python value for the row and column. This uses the row_header_data and column_data accessors to extract values for the row and column. Parameters ---------- row : sequence of int The indices of the row as a sequence from root to leaf. column : sequence of int The indices of the column as a sequence of length 0 or 1. Returns ------- value : any The value represented by the given row and column. """ if len(column) == 0: column_data = self.row_header_data else: column_data = self.column_data[column[0]] if len(row) == 0: return column_data.title obj = self.data[row[0]] return column_data.get_value(obj)
[docs] def can_set_value(self, row, column): """ Whether the value in the indicated row and column can be set. This uses the row_header_data and column_data accessors to determine if the value may be changed. Parameters ---------- row : sequence of int The indices of the row as a sequence from root to leaf. column : sequence of int The indices of the column as a sequence of length 0 or 1. Returns ------- can_set_value : bool Whether or not the value can be set. """ if len(row) == 0: return False if len(column) == 0: column_data = self.row_header_data else: column_data = self.column_data[column[0]] obj = self.data[row[0]] return column_data.can_set_value(obj)
[docs] def set_value(self, row, column, value): """ Set the Python value for the row and column. This uses the row_header_data and column_data accessors to set the value. Parameters ---------- row : sequence of int The indices of the row as a sequence from root to leaf. column : sequence of int The indices of the column as a sequence of length 0 or 1. value : any The new value for the given row and column. Raises ------- DataViewSetError If the value cannot be set. """ if len(row) == 0: raise DataViewSetError("Can't set column titles.") if len(column) == 0: column_data = self.row_header_data else: column_data = self.column_data[column[0]] obj = self.data[row[0]] column_data.set_value(obj, value) self.values_changed = (row, column, row, column)
[docs] def get_value_type(self, row, column): """ Return the value type of the given row and column. This uses the row_header_data and column_data accessors to get the value type. Parameters ---------- row : sequence of int The indices of the row as a sequence from root to leaf. column : sequence of int The indices of the column as a sequence of length 0 or 1. Returns ------- value_type : AbstractValueType or None The value type of the given row and column, or None if no value should be displayed. """ if len(column) == 0: column_data = self.row_header_data else: column_data = self.column_data[column[0]] if len(row) == 0: return column_data.title_type return column_data.value_type
# data update methods @observe("data") def _update_data(self, event): self.structure_changed = True @observe(trait("data", notify=False).list_items(optional=True)) def _update_data_items(self, event): if len(event.added) != len(event.removed): # number of rows has changed self.structure_changed = True else: if isinstance(event.index, int): start = event.index stop = min(event.index + len(event.added), len(self.data)) - 1 else: start = event.index.start stop = min(event.index.stop, len(self.data)) - 1 self.values_changed = ((start,), (), (stop,), ()) @observe('row_header_data') def _update_row_header_data(self, event): self.values_changed = ((), (), (), ()) @observe('row_header_data:updated') def _update_row_header_data_event(self, event): if event.new[1] == 'value': if len(self.data) > 0: self.values_changed = ((0,), (), (len(self.data) - 1,), ()) else: self.values_changed = ((), (), (), ()) @observe('column_data.items') def _update_all_column_data_items(self, event): self.structure_changed = True @observe('column_data:items:updated') def _update_column_data(self, event): index = self.column_data.index(event.new[0]) if event.new[1] == 'value': if len(self.data) > 0: self.values_changed = ( (0,), (index,), (len(self.data) - 1,), (index,) ) else: self.values_changed = ((), (index,), (), (index,)) # default data value def _data_default(self): return []