From 3d262b8b82bf1e2868fad8aa64c7422276f3239f Mon Sep 17 00:00:00 2001
From: Edouard DUPIN <yui.heero@gmail.com>
Date: Mon, 31 May 2021 21:57:37 +0200
Subject: [PATCH] [DEV] add a real Signal interface

---
 src/org/atriasoft/esignal/Connection.java     |  29 +++-
 .../esignal/ConnectionRemoveInterface.java    |   5 +
 src/org/atriasoft/esignal/Signal.java         | 141 +++++++++++++++---
 3 files changed, 149 insertions(+), 26 deletions(-)
 create mode 100644 src/org/atriasoft/esignal/ConnectionRemoveInterface.java

diff --git a/src/org/atriasoft/esignal/Connection.java b/src/org/atriasoft/esignal/Connection.java
index 1282723..68aec53 100644
--- a/src/org/atriasoft/esignal/Connection.java
+++ b/src/org/atriasoft/esignal/Connection.java
@@ -1,10 +1,31 @@
 package org.atriasoft.esignal;
 
-public class Connection {
+import java.lang.ref.WeakReference;
+
+public class Connection implements AutoCloseable {
+	protected final WeakReference<ConnectionRemoveInterface> connection;
 	
 	public void disconnect() {
-		// TODO Auto-generated method stub
-		
+		close();
+	}
+
+	public Connection( final ConnectionRemoveInterface object ) {
+		this.connection = new WeakReference<>(object);
+	}
+
+	public Connection() {
+		this.connection = null;
+	}
+
+	@Override
+	public void close() {
+		if (this.connection == null) {
+			return;
+		}
+		ConnectionRemoveInterface tmp = this.connection.get();
+		if (tmp == null) {
+			return;
+		}
+		tmp.disconnect(this);
 	}
-	
 }
diff --git a/src/org/atriasoft/esignal/ConnectionRemoveInterface.java b/src/org/atriasoft/esignal/ConnectionRemoveInterface.java
new file mode 100644
index 0000000..fe80970
--- /dev/null
+++ b/src/org/atriasoft/esignal/ConnectionRemoveInterface.java
@@ -0,0 +1,5 @@
+package org.atriasoft.esignal;
+
+public interface ConnectionRemoveInterface {
+	void disconnect(final Connection connection);
+}
diff --git a/src/org/atriasoft/esignal/Signal.java b/src/org/atriasoft/esignal/Signal.java
index 04af838..f637ebf 100644
--- a/src/org/atriasoft/esignal/Signal.java
+++ b/src/org/atriasoft/esignal/Signal.java
@@ -7,8 +7,8 @@ import java.util.List;
 import java.util.function.Consumer;
 
 class ConnectedElement<T> {
-	private final Consumer<T> consumer;
-	private final WeakReference<Object> reference;
+	protected final Consumer<T> consumer;
+	protected final WeakReference<Object> reference;
 	
 	public ConnectedElement(final WeakReference<Object> reference, final Consumer<T> consumer) {
 		this.reference = reference;
@@ -22,38 +22,135 @@ class ConnectedElement<T> {
 	public WeakReference<Object> getReference() {
 		return this.reference;
 	}
+	public Object getIfAlive() {
+		return this.reference.get();
+	}
+	public boolean isCompatibleWith(final Object elem) {
+		Object out = this.reference.get();
+		if (out == elem) {
+			return true;
+		}
+		return false;
+	}
+}
+class ConnectedElementDynamic<T> extends ConnectedElement<T> {
+	protected final WeakReference<Connection> connection;
+	
+	public ConnectedElementDynamic(final WeakReference<Connection> connection, final WeakReference<Object> reference, final Consumer<T> consumer) {
+		super(reference, consumer);
+		this.connection = connection;
+	}
+	
+	public WeakReference<Connection> getConnection() {
+		return this.connection;
+	}
+	
+	@Override
+	public Object getIfAlive() {
+		Object out = this.reference.get();
+		if (out == null) {
+			return null;
+		}
+		Object outConnection = this.connection.get();
+		if (outConnection == null) {
+			return null;
+		}
+		return out;
+	}
+	@Override
+	public boolean isCompatibleWith(final Object elem) {
+		if (super.isCompatibleWith(elem)) {
+			return true;
+		}
+		Object outConnection = this.connection.get();
+		if (outConnection == elem) {
+			return true;
+		}
+		return false;
+	}
 	
 }
 
-public class Signal<T> {
-	
+public class Signal<T> implements ConnectionRemoveInterface {
 	List<ConnectedElement<T>> data = new ArrayList<>();
 	
-	public void clear(final Object obj) {
-		
+	public void clear() {
+		synchronized(this.data) {
+			this.data = new ArrayList<>();
+		}
 	}
-	
-	public Connection connect(final Object reference, final T fucntion) {
-		
-		return null;
+
+	public void connect(final Object reference, final Consumer<T> function) {
+		synchronized(this.data) {
+			WeakReference<Object> weakRef = new WeakReference<Object>(reference);
+			this.data.add(new ConnectedElement<T>(weakRef, function));
+		}
 	}
-	
-	public void disconnect(final Connection connection) {
-		
-	}
-	
 	public void disconnect(final Object obj) {
-		
+		synchronized(this.data) {
+			final Iterator<ConnectedElement<T>> iterator = this.data.iterator();
+			while (iterator.hasNext()) {
+				final ConnectedElement<T> elem = iterator.next();
+				if (elem.isCompatibleWith(obj)) {
+					iterator.remove();
+				}
+			}
+		}
 	}
+	public Connection connectDynamic(final Object reference, final Consumer<T> function) {
+		WeakReference<Object> weakRef = new WeakReference<Object>(reference);
+		Connection out = new Connection(this); 
+		WeakReference<Connection> weakConnection = new WeakReference<Connection>(out);
+		synchronized(this.data) {
+			this.data.add(new ConnectedElementDynamic<T>(weakConnection, weakRef, function));
+		}
+		return out;
+	}
+	
+	@Override
+	public void disconnect(final Connection connection) {
+		synchronized(this.data) {
+			final Iterator<ConnectedElement<T>> iterator = this.data.iterator();
+			while (iterator.hasNext()) {
+				final ConnectedElement<T> elem = iterator.next();
+				if (elem.isCompatibleWith(connection)) {
+					iterator.remove();
+				}
+			}
+		}
+	}
+	
 	
 	public void emit(final T value) {
-		final Iterator<ConnectedElement<T>> iterator = this.data.iterator();
-		while (iterator.hasNext()) {
-			final ConnectedElement<T> elem = iterator.next();
-			if (elem.getReference().get() == null) {
-				iterator.remove();
+		List<ConnectedElement<T>> tmp;
+		// clean the list:
+		synchronized(this.data) {
+			final Iterator<ConnectedElement<T>> iterator = this.data.iterator();
+			while (iterator.hasNext()) {
+				final ConnectedElement<T> elem = iterator.next();
+				Object tmpObject = elem.getIfAlive();
+				if (tmpObject == null) {
+					iterator.remove();
+				}
+			}
+			// simple optimization:
+			if (this.data.isEmpty()) {
+				return;
+			}
+			// clone the list to permit to have asynchronous remove call
+			tmp = new ArrayList<>(this.data);
+		}
+		// real call elements
+		{
+		final Iterator<ConnectedElement<T>> iterator = tmp.iterator();
+			while (iterator.hasNext()) {
+				final ConnectedElement<T> elem = iterator.next();
+				Object tmpObject = elem.getIfAlive();
+				if (tmpObject == null) {
+					continue;
+				}
+				elem.getConsumer().accept(value);
 			}
-			elem.getConsumer().accept(value);
 		}
 	}