From 598f38921fa195af007d7f28e3cc40de1904575f Mon Sep 17 00:00:00 2001
From: Chris Lenk <clenk@mitre.org>
Date: Wed, 6 Sep 2017 16:20:16 -0400
Subject: [PATCH] Start Environment layer

---
 stix2/environment.py      | 64 ++++++++++++++++++++++++++++++++++++---
 stix2/sources/__init__.py | 16 +++++-----
 2 files changed, 68 insertions(+), 12 deletions(-)

diff --git a/stix2/environment.py b/stix2/environment.py
index f855755..91f0676 100644
--- a/stix2/environment.py
+++ b/stix2/environment.py
@@ -1,11 +1,10 @@
 import copy
 
+from .sources import CompositeDataSource
+
 
 class ObjectFactory(object):
-    """Object Factory
-
-    Used to easily create STIX objects with default values for certain
-    properties.
+    """Easily create STIX objects with default values for certain properties.
 
     Args:
         created_by_ref: Default created_by_ref value to apply to all
@@ -66,3 +65,60 @@ class ObjectFactory(object):
             properties.update(**kwargs)
 
         return cls(**properties)
+
+
+class Environment(object):
+    """
+
+    Args:
+        factory (ObjectFactory): Factory for creating objects with common
+            defaults for certain properties.
+        store (DataStore): Data store providing the source and sink for the
+            environment.
+        source (DataSource): Source for retrieving STIX objects.
+        sink (DataSink): Destination for saving STIX objects.
+            Invalid if `store` is also provided.
+    """
+
+    def __init__(self, factory=None, store=None, source=None, sink=None):
+        self.factory = factory
+        self.source = CompositeDataSource()
+        if store:
+            self.source.add_data_source(store.source)
+            self.sink = store.sink
+        if source:
+            self.source.add_data_source(source)
+        if sink:
+            if store:
+                raise ValueError("Data store already provided! Environment may only have one data sink.")
+            self.sink = sink
+
+        def create(self, *args, **kwargs):
+            """Use the object factory to create a STIX object with default property values.
+            """
+            return self.factory.create(*args, **kwargs)
+
+        def get(self, *args, **kwargs):
+            """Retrieve the most recent version of a single STIX object by ID.
+            """
+            return self.source.get(*args, **kwargs)
+
+        def all_versions(self, *args, **kwargs):
+            """Retrieve all versions of a single STIX object by ID.
+            """
+            return self.source.all_versions(*args, **kwargs)
+
+        def query(self, *args, **kwargs):
+            """Retrieve STIX objects matching a set of filters.
+            """
+            return self.source.query(*args, **kwargs)
+
+        def add_filter(self, *args, **kwargs):
+            """Add a filter to be applied to all queries for STIX objects from this environment.
+            """
+            return self.source.add_filter(*args, **kwargs)
+
+        def add(self, *args, **kwargs):
+            """Store a STIX object.
+            """
+            return self.sink.add(*args, **kwargs)
diff --git a/stix2/sources/__init__.py b/stix2/sources/__init__.py
index b50fd1d..08063f5 100644
--- a/stix2/sources/__init__.py
+++ b/stix2/sources/__init__.py
@@ -5,7 +5,7 @@ Classes:
     DataStore
     DataSink
     DataSource
-    STIXCommonPropertyFilters
+    CompositeDataSource
 
 TODO:Test everything
 
@@ -226,7 +226,7 @@ class DataSource(object):
         self.filters.add(filter)
 
     def apply_common_filters(self, stix_objs, query):
-        """Evaluates filters against a set of STIX 2.0 objects
+        """Evaluate filters against a set of STIX 2.0 objects.
 
         Supports only STIX 2.0 common property fields
 
@@ -300,11 +300,10 @@ class DataSource(object):
 
 
 class CompositeDataSource(DataSource):
-    """Composite Data Source
+    """Controller for all the defined/configured STIX Data Sources.
 
-    Acts as a controller for all the defined/configured STIX Data Sources
-    e.g. a user can define n Data Sources - creating Data Source (objects)
-    for each. There is only one instance of this for any python STIX 2.0
+    E.g. a user can define n Data Sources - creating Data Source (objects)
+    for each. There is only one instance of this for any Python STIX 2.0
     application.
 
     Attributes:
@@ -314,8 +313,7 @@ class CompositeDataSource(DataSource):
 
     """
     def __init__(self):
-        """
-        Creates a new STIX Data Source.
+        """Create a new STIX Data Source.
 
         Args:
             name (str): A string containing the name to attach in the
@@ -448,6 +446,8 @@ class CompositeDataSource(DataSource):
                 to the Composite Data Source
 
         """
+        if not isinstance(data_sources, list):
+            data_sources = [data_sources]
         for ds in data_sources:
             if issubclass(ds.__class__, DataSource):
                 if ds.id in self.data_sources: