From d7d41b878c19dd2958c1b1e5b810de49e5c15fe5 Mon Sep 17 00:00:00 2001
From: Sven Heidemann <sven.heidemann@sh-edraft.de>
Date: Sat, 15 Apr 2023 19:21:11 +0200
Subject: [PATCH] Added behavior subject

---
 .../behavior_subject.py                       | 23 +++++++++++++++++++
 src/cpl_reactive_extensions/subject.py        | 11 ---------
 .../reactive_test_case.py                     | 12 ++++++++++
 3 files changed, 35 insertions(+), 11 deletions(-)
 create mode 100644 src/cpl_reactive_extensions/behavior_subject.py

diff --git a/src/cpl_reactive_extensions/behavior_subject.py b/src/cpl_reactive_extensions/behavior_subject.py
new file mode 100644
index 00000000..18b087c0
--- /dev/null
+++ b/src/cpl_reactive_extensions/behavior_subject.py
@@ -0,0 +1,23 @@
+from cpl_core.type import T
+from cpl_reactive_extensions.observable import Observable
+
+
+class BehaviorSubject(Observable):
+    def __init__(self, _t: type, value: T):
+        Observable.__init__(self, lambda x: x)
+
+        if not isinstance(value, _t):
+            raise TypeError(f"Expected {_t.__name__} not {type(value).__name__}")
+
+        self._t = _t
+        self._value = value
+
+    @property
+    def value(self) -> T:
+        return self._value
+
+    def next(self, value: T):
+        if not isinstance(value, self._t):
+            raise TypeError(f"Expected {self._t.__name__} not {type(value).__name__}")
+
+        self._value = value
diff --git a/src/cpl_reactive_extensions/subject.py b/src/cpl_reactive_extensions/subject.py
index 0b0e25bb..864ea2b2 100644
--- a/src/cpl_reactive_extensions/subject.py
+++ b/src/cpl_reactive_extensions/subject.py
@@ -7,14 +7,3 @@ class Subject(Observable):
         Observable.__init__(self)
 
         self._t = _t
-        self._value: T = None
-
-    @property
-    def value(self) -> T:
-        return self._value
-
-    def next(self, value: T):
-        if not isinstance(value, self._t):
-            raise TypeError(f"Expected {self._t.__name__} not {type(value).__name__}")
-
-        self._value = value
diff --git a/unittests/unittests_reactive_extenstions/reactive_test_case.py b/unittests/unittests_reactive_extenstions/reactive_test_case.py
index 7b590394..96a28979 100644
--- a/unittests/unittests_reactive_extenstions/reactive_test_case.py
+++ b/unittests/unittests_reactive_extenstions/reactive_test_case.py
@@ -4,6 +4,7 @@ import unittest
 from threading import Timer
 
 from cpl_core.console import Console
+from cpl_reactive_extensions.behavior_subject import BehaviorSubject
 from cpl_reactive_extensions.observable import Observable
 from cpl_reactive_extensions.observer import Observer
 from cpl_reactive_extensions.subject import Subject
@@ -114,3 +115,14 @@ class ReactiveTestCase(unittest.TestCase):
         observable.subscribe(subject, self._on_error)
 
         self.assertFalse(self._error)
+
+    def test_behavior_subject(self):
+        subject = BehaviorSubject(int, 0)
+
+        subject.subscribe(lambda x: Console.write_line("a", x))
+
+        subject.next(1)
+        subject.next(2)
+
+        subject.subscribe(lambda x: Console.write_line("b", x))
+        subject.next(3)