From fc4694b5aae5364b5677cc034e23601246fa5b2f Mon Sep 17 00:00:00 2001
From: Mateusz Warowny <mmzwarowny@dundee.ac.uk>
Date: Tue, 4 Jul 2023 10:15:11 +0200
Subject: [PATCH] JAL-4199 Allow multiple listeners in TaskEventSupport

---
 src/jalview/ws2/helpers/TaskEventSupport.java |   65 ++++++++++++++++---------
 1 file changed, 42 insertions(+), 23 deletions(-)

diff --git a/src/jalview/ws2/helpers/TaskEventSupport.java b/src/jalview/ws2/helpers/TaskEventSupport.java
index c7b6052..dcf965a 100644
--- a/src/jalview/ws2/helpers/TaskEventSupport.java
+++ b/src/jalview/ws2/helpers/TaskEventSupport.java
@@ -1,6 +1,7 @@
 package jalview.ws2.helpers;
 
 import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
 
 import jalview.ws2.actions.api.JobI;
 import jalview.ws2.actions.api.TaskEventListener;
@@ -9,52 +10,70 @@ import jalview.ws2.api.JobStatus;
 
 public class TaskEventSupport<T>
 {
-  TaskI<T> source;
-  TaskEventListener<T> handler;
-  
-  public TaskEventSupport(TaskI<T> source, TaskEventListener<T> handler)
+  private TaskI<T> source;
+
+  private List<TaskEventListener<T>> listeners = new CopyOnWriteArrayList<>();
+
+  public TaskEventSupport(TaskI<T> source)
   {
     this.source = source;
-    this.handler = handler;
+  }
+
+  public TaskEventSupport(TaskI<T> source, TaskEventListener<T> handler)
+  {
+    this(source);
+    addListener(handler);
+  }
+
+  public void addListener(TaskEventListener<T> listener)
+  {
+    listeners.add(listener);
   }
   
+  public void removeListener(TaskEventListener<T> listener)
+  {
+    listeners.remove(listener);
+  }
+
   public void fireTaskStarted(List<? extends JobI> subJobs)
   {
-    handler.taskStarted(source, subJobs);
+    for (var listener : listeners)
+      listener.taskStarted(source, subJobs);
   }
-  
+
   public void fireTaskStatusChanged(JobStatus status)
   {
-    handler.taskStatusChanged(source, status);
+    for (var listener : listeners)
+      listener.taskStatusChanged(source, status);
   }
-  
+
   public void fireTaskCompleted(T result)
   {
-    handler.taskCompleted(source, result);
+    for (var listener : listeners)
+      listener.taskCompleted(source, result);
   }
-  
+
   public void fireTaskException(Exception e)
   {
-    handler.taskException(source, e);
-  }
-  
-  public void fireTaskRestarted()
-  {
-    handler.taskRestarted(source);
+    for (var listener : listeners)
+      listener.taskException(source, e);
   }
-  
+
   public void fireSubJobStatusChanged(JobI job, JobStatus status)
   {
-    handler.subJobStatusChanged(source, job, status);
+    for (var listener : listeners)
+      listener.subJobStatusChanged(source, job, status);
   }
-  
+
   public void fireSubJobLogChanged(JobI job, String log)
   {
-    handler.subJobLogChanged(source, job, log);
+    for (var listener : listeners)
+      listener.subJobLogChanged(source, job, log);
   }
-  
+
   public void fireSubJobErrorLogChanged(JobI job, String log)
   {
-    handler.subJobErrorLogChanged(source, job, log);
+    for (var listener : listeners)
+      listener.subJobErrorLogChanged(source, job, log);
   }
 }
-- 
1.7.10.2