From 8170c932557a96a0b1f21e8af30a20d14992210e Mon Sep 17 00:00:00 2001
From: Alexander <alexander@zhirov.kz>
Date: Fri, 11 Nov 2022 03:03:18 +0300
Subject: [PATCH] observer CurrentConditionsDisplay

---
 observer/app.d                      | 14 ++++++++
 observer/currentconditionsdisplay.d | 31 ++++++++++++++++
 observer/displayelement.d           |  6 ++++
 observer/observer.d                 |  6 ++++
 observer/subject.d                  |  9 +++++
 observer/weatherdata.d              | 55 +++++++++++++++++++++++++++++
 6 files changed, 121 insertions(+)
 create mode 100644 observer/app.d
 create mode 100644 observer/currentconditionsdisplay.d
 create mode 100644 observer/displayelement.d
 create mode 100644 observer/observer.d
 create mode 100644 observer/subject.d

diff --git a/observer/app.d b/observer/app.d
new file mode 100644
index 0000000..9ffcf5e
--- /dev/null
+++ b/observer/app.d
@@ -0,0 +1,14 @@
+module observer.app;
+
+import observer.weatherdata;
+import observer.currentconditionsdisplay;
+
+void main()
+{
+    WeatherData weatherData = new WeatherData();
+    CurrentConditionsDisplay currentDisplay = new CurrentConditionsDisplay(weatherData);
+
+    weatherData.setMeasurements(80, 65, 30.4f);
+    weatherData.setMeasurements(82, 70, 29.2f);
+    weatherData.setMeasurements(78, 90, 29.2f);
+}
diff --git a/observer/currentconditionsdisplay.d b/observer/currentconditionsdisplay.d
new file mode 100644
index 0000000..815d082
--- /dev/null
+++ b/observer/currentconditionsdisplay.d
@@ -0,0 +1,31 @@
+module observer.currentconditionsdisplay;
+import observer.displayelement;
+import observer.observer;
+import observer.weatherdata;
+import std.stdio : writeln;
+import std.format : format;
+
+class CurrentConditionsDisplay : Observer, DisplayElement
+{
+private:
+    float temperature;
+    float humidity;
+    WeatherData weatherData;
+public:
+    this(WeatherData weatherData)
+    {
+        weatherData.registerObserver(this);
+    }
+
+    override void update(float temperature, float humidity, float pressure)
+    {
+        this.temperature = temperature;
+        this.humidity = humidity;
+        display();
+    }
+
+    override void display()
+    {
+        writeln("Current conditions: %3.1f".format(temperature), "F degrees and %3.1f%% humidity".format(humidity));
+    }
+}
diff --git a/observer/displayelement.d b/observer/displayelement.d
new file mode 100644
index 0000000..5154dfc
--- /dev/null
+++ b/observer/displayelement.d
@@ -0,0 +1,6 @@
+module observer.displayelement;
+
+interface DisplayElement
+{
+    void display();
+}
diff --git a/observer/observer.d b/observer/observer.d
new file mode 100644
index 0000000..a4e5e08
--- /dev/null
+++ b/observer/observer.d
@@ -0,0 +1,6 @@
+module observer.observer;
+
+interface Observer
+{
+    void update(float temp, float humidity, float pressure);
+}
diff --git a/observer/subject.d b/observer/subject.d
new file mode 100644
index 0000000..668feb0
--- /dev/null
+++ b/observer/subject.d
@@ -0,0 +1,9 @@
+module observer.subject;
+import observer.observer;
+
+interface Subject
+{
+    void registerObserver(Observer o);
+    void removeObserver(Observer o);
+    void notifyObservers();
+}
diff --git a/observer/weatherdata.d b/observer/weatherdata.d
index e6df941..f097f47 100644
--- a/observer/weatherdata.d
+++ b/observer/weatherdata.d
@@ -1,2 +1,57 @@
 module observer.weatherdata;
+import observer.subject;
+import observer.observer;
+import std.algorithm : remove, countUntil;
 
+class WeatherData : Subject
+{
+private:
+    Observer[] observers;
+    float temperature, humidity, pressure;
+public:
+    override void registerObserver(Observer o)
+    {
+        observers ~= o;
+    }
+    
+    override void removeObserver(Observer o)
+    {
+        observers.remove(observers.countUntil(o));
+    }
+
+    override void notifyObservers()
+    {
+        foreach (Observer o; observers)
+        {
+            o.update(temperature, humidity, pressure);
+        }
+    }
+
+    void measurementsChanged()
+    {
+        notifyObservers();
+    }
+
+    void setMeasurements(float temperature, float humidity, float pressure)
+    {
+        this.temperature = temperature;
+        this.humidity = humidity;
+        this.pressure = pressure;
+        measurementsChanged();
+    }
+
+    @property float getTemperature()
+    {
+        return temperature;
+    }
+
+    @property float getHumidity()
+    {
+        return humidity;
+    }
+
+    @property float getPressure()
+    {
+        return pressure;
+    }
+}