From 59afdc935cc4455d8ade9264b81b3cf7a8223eda Mon Sep 17 00:00:00 2001
From: Christian Femers <femers@in.tum.de>
Date: Thu, 19 Sep 2019 18:11:15 +0200
Subject: [PATCH] Added a listener system to project specific machine context

---
 .../plugin/nature/MachineContext.java         | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/plugins/net.mograsim.plugin.core/src/net/mograsim/plugin/nature/MachineContext.java b/plugins/net.mograsim.plugin.core/src/net/mograsim/plugin/nature/MachineContext.java
index b434ec97..b1708482 100644
--- a/plugins/net.mograsim.plugin.core/src/net/mograsim/plugin/nature/MachineContext.java
+++ b/plugins/net.mograsim.plugin.core/src/net/mograsim/plugin/nature/MachineContext.java
@@ -1,8 +1,10 @@
 package net.mograsim.plugin.nature;
 
 import java.io.IOException;
+import java.util.HashSet;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 import org.eclipse.core.resources.IProject;
 import org.eclipse.jface.util.PropertyChangeEvent;
@@ -20,6 +22,8 @@ public class MachineContext
 	Optional<MachineDefinition> machineDefinition;
 	Optional<Machine> activeMachine;
 
+	private final Set<ActiveMachineListener> observers = new HashSet<>();
+
 	public MachineContext(IProject owner)
 	{
 		this.owner = Objects.requireNonNull(owner);
@@ -87,6 +91,7 @@ public class MachineContext
 	public final void setActiveMachine(Machine machine)
 	{
 		activeMachine = Optional.ofNullable(machine);
+		notifyObservers();
 	}
 
 	public final Optional<String> getMachineId()
@@ -117,4 +122,26 @@ public class MachineContext
 			updateDefinition();
 		}
 	}
+
+	public void registerObserver(ActiveMachineListener ob)
+	{
+		observers.add(ob);
+		ob.setMachine(activeMachine);
+	}
+
+	public void deregisterObserver(ActiveMachineListener ob)
+	{
+		observers.remove(ob);
+	}
+
+	private void notifyObservers()
+	{
+		observers.forEach(ob -> ob.setMachine(activeMachine));
+	}
+
+	@FunctionalInterface
+	public static interface ActiveMachineListener
+	{
+		void setMachine(Optional<Machine> machine);
+	}
 }
\ No newline at end of file
-- 
2.17.1