add append for Datasets in Data objects

src/hdmf/common/table.py

@@ -38,7 +38,7 @@ def __init__(self, **kwargs):
     @docval({'name': 'val', 'type': None, 'doc': 'the value to add to this column'})
     def add_row(self, **kwargs):
         val = getargs('val', kwargs)
-        self.data.append(val)
+        self.append(val)
 
 
 @register_class('VectorIndex')
@@ -332,7 +332,7 @@ def add_row(self, **kwargs):
             row_id = data.pop('id', None)
         if row_id is None:
             row_id = len(self)
-        self.id.data.append(row_id)
+        self.id.append(row_id)
 
         for colname, colnum in self.__colids.items():
             if colname not in data:

src/hdmf/container.py

@@ -5,6 +5,7 @@
 from .utils import docval, get_docval, call_docval_func, getargs, ExtenderMeta
 from .data_utils import DataIO
 from warnings import warn
+import h5py
 
 
 class AbstractContainer(with_metaclass(ExtenderMeta, object)):
@@ -414,6 +415,11 @@ def append(self, arg):
             self.data.append(arg)
         elif isinstance(self.data, np.ndarray):
             self.__data = np.append(self.__data, [arg])
+        elif isinstance(self.data, h5py.Dataset):
+            shape = list(self.__data.shape)
+            shape[0] += 1
+            self.__data.resize(shape)
+            self.__data[-1] = arg
         else:
             msg = "Data cannot append to object of type '%s'" % type(self.__data)
             raise ValueError(msg)
@@ -423,6 +429,11 @@ def extend(self, arg):
             self.data.extend(arg)
         elif isinstance(self.data, np.ndarray):
             self.__data = np.append(self.__data, [arg])
+        elif isinstance(h5py.Dataset):
+            shape = list(self.__data.shape)
+            shape[0] += len(arg)
+            self.__data.resize(shape)
+            self.__data[-len(arg):] = arg
         else:
             msg = "Data cannot extend object of type '%s'" % type(self.__data)
             raise ValueError(msg)