chaching

Author: Jhsmit

pyhdx/web/cache.py

@@ -0,0 +1,16 @@
+import param
+
+
+class Cache(param.Parameterized):
+    pass
+
+
+class MemoryCache(param.Parameterized):
+
+    _cache = param.Dict(default={})
+
+    def __getitem__(self, item):
+        return self._cache.get(item)
+
+    def __setitem__(self, key, value):
+        self._cache[key] = value

pyhdx/web/sources.py

@@ -23,7 +23,13 @@ def get(self):
 
 class TableSource(Source):
 
-    tables = param.Dict({})
+    tables = param.Dict(
+        default={},
+        doc="Dictionary of tables (pd.DataFrames)")
+
+    hashes = param.Dict(
+        default={},
+        doc="Dictionary of table hashes")
 
     _type = 'table'
 

pyhdx/web/transforms.py

@@ -21,6 +21,8 @@ class Transform(param.Parameterized):
 
     redrawn = param.Event(doc="event gets triggered when widgets are changed and the controller needs to redraw them")
 
+    cache = param.ClassSelector(class_=Cache)
+
     def __init__(self, **params):
         super().__init__(**params)
 
@@ -53,6 +55,12 @@ def get(self):
         df = self.source.get_table(self.table)  # returns None on KeyError #todo change to source.get_table
         return df
 
+    @property
+    def hash(self):
+        # or sources can have multiple hashes?
+        # / objects can have multiple hashes?
+        return tuple([self._type, self.table, self.source.hashes[self.table]])
+
     @param.depends('table', watch=True)
     def _table_updated(self):
         self.updated = True