Switch Build Asset Template to abstract base class

openpype/hosts/maya/api/template_loader.py

@@ -22,7 +22,8 @@ def import_template(self, path):
  ValueError: "Build already generated"
  """
  if cmds.objExists(PLACEHOLDER_SET):
- raise ValueError("Build already generated. Please clean scene")
+ raise ValueError("Build already generated. Please clean scene if "
+ "you really want to rebuild. (File>New Scene)")
  cmds.sets(name=PLACEHOLDER_SET, empty=True)
  self.new_nodes = cmds.file(path, i=True, returnNewNodes=True)
  cmds.setAttr(PLACEHOLDER_SET + '.hiddenInOutliner', True)

openpype/lib/abstract_load_template.py

@@ -1,12 +1,17 @@
 import os
 import re
 import avalon
+from abc import ABCMeta, abstractmethod
+
+import six
+
 from openpype.settings import get_project_settings
 from openpype.lib import Anatomy, get_linked_assets, get_loaders_by_name,\
  collect_last_version_repres
 
 
-class AbstractTemplateLoader(object):
+@six.add_metaclass(ABCMeta)
+class AbstractTemplateLoader:
  """
  Abstraction of Template Loader.
 
@@ -85,8 +90,8 @@ def template_path(self):
 
  if not os.path.exists(solved_path):
  raise IOError(
- "Template found in openPype settings for task '{}' with DCC \
- '{}' does not exists. (Not found : {})".format(
+ "Template found in openPype settings for task '{}' with DCC "
+ "'{}' does not exists. (Not found : {})".format(
  current_task, current_dcc, solved_path))
  return solved_path
 
@@ -158,6 +163,7 @@ def populate_template(self, current_asset,
  print("or that the build template is malformed, "
  "continue at your own risks.")
 
+ @abstractmethod
  def import_template(self, template_path):
  """
  Import template in current dcc
@@ -169,8 +175,9 @@ def import_template(self, template_path):
  Return:
  None
  """
- raise NotImplementedError
+ pass
 
+ @abstractmethod
  def get_template_nodes(self):
  """
  Returning a list of nodes acting as DCC placeholders for
@@ -183,9 +190,10 @@ def get_template_nodes(self):
  Returns:
  list(AnyNode): Solved template path
  """
- raise NotImplementedError
+ pass
 
 
+@six.add_metaclass(ABCMeta)
 class AbstractPlaceholder:
  """Abstraction of placeholders logic
 
@@ -215,6 +223,7 @@ class AbstractPlaceholder:
  def __init__(self, node):
  self.get_data(node)
 
+ @abstractmethod
  def get_data(self, node):
  """
  Collect placeholders information.
@@ -265,6 +274,7 @@ def is_valid(self):
  """
  return set(self.attributes).issubset(self.data.keys())
 
+ @abstractmethod
  def parent_in_hierarchy(self, containers):
  """Place container in correct hierarchy
  given by placeholder
@@ -275,6 +285,7 @@ def parent_in_hierarchy(self, containers):
  """
  raise NotImplementedError
 
+ @abstractmethod
  def clean(self):
  """Clean placeholder from hierarchy after loading assets.
  """