From 4076999c53315133e8d4ff9023b23131bf001e87 Mon Sep 17 00:00:00 2001
From: Mateusz Warowny <mmzwarowny@dundee.ac.uk>
Date: Wed, 19 Jan 2022 14:45:41 +0100
Subject: [PATCH] JAL-3878 Move listeners list from the WebServiceDiscoverer
 interface.

Listeners list defined in the interface was globally shared
among all discoverer instances. Listeners should be kept by
the discoverer instance instead.
---
 src/jalview/ws2/OperationsChangeListenerList.java |   62 +++++++++++++++++++++
 src/jalview/ws2/WebServiceDiscovererI.java        |   31 +----------
 src/jalview/ws2/slivka/SlivkaWSDiscoverer.java    |   22 ++++++++
 3 files changed, 86 insertions(+), 29 deletions(-)
 create mode 100644 src/jalview/ws2/OperationsChangeListenerList.java

diff --git a/src/jalview/ws2/OperationsChangeListenerList.java b/src/jalview/ws2/OperationsChangeListenerList.java
new file mode 100644
index 0000000..275fab3
--- /dev/null
+++ b/src/jalview/ws2/OperationsChangeListenerList.java
@@ -0,0 +1,62 @@
+package jalview.ws2;
+
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
+import jalview.ws2.WebServiceDiscovererI.OperationsChangeListener;
+import jalview.ws2.operations.Operation;
+
+/**
+ * A helper class that manages a list of OperationsChangeListeners
+ * Used by web service discoverers to store listeners.
+ * @author mmwarowny
+ *
+ */
+public class OperationsChangeListenerList
+{
+  private List<OperationsChangeListener> listeners = new CopyOnWriteArrayList<>();
+  private WebServiceDiscovererI discoverer;
+  
+  public OperationsChangeListenerList(WebServiceDiscovererI discoverer)
+  {
+    this.discoverer = discoverer;
+  }
+  
+  /**
+   * Add an operations list observer that will be notified of any changes.
+   * 
+   * @param listener
+   *          operations list listener
+   */
+  public void addListener(OperationsChangeListener listener)
+  {
+    listeners.add(listener);
+  }
+
+  /**
+   * Remove the listener from the observers list.
+   * 
+   * @param listener
+   *          listener to be removed
+   */
+  public void removeListener(OperationsChangeListener listener)
+  {
+    listeners.remove(listener);
+  }
+
+  /**
+   * Called whenever the list of operations changes. Notifies all listeners of
+   * the change to the operations list. Typically, should be called with an
+   * empty list at the beginning of the service discovery process and for the
+   * second time with the list of discovered operations after that.
+   * 
+   * @param list
+   *          new list of discovered operations
+   */
+  public void fireOperationsChanged(List<Operation> list)
+  {
+    for (var listener : listeners)
+    {
+      listener.operationsChanged(discoverer, list);
+    }
+  }
+}
diff --git a/src/jalview/ws2/WebServiceDiscovererI.java b/src/jalview/ws2/WebServiceDiscovererI.java
index 30cc22e..f70fee9 100644
--- a/src/jalview/ws2/WebServiceDiscovererI.java
+++ b/src/jalview/ws2/WebServiceDiscovererI.java
@@ -123,19 +123,13 @@ public interface WebServiceDiscovererI
         List<Operation> operations);
   }
 
-  List<OperationsChangeListener> serviceListeners = new CopyOnWriteArrayList<>();
-
   /**
    * Add an operations list observer that will be notified of any changes.
    * 
    * @param listener
    *          operations list listener
    */
-  public default void addOperationsChangeListener(
-      OperationsChangeListener listener)
-  {
-    serviceListeners.add(listener);
-  }
+  public void addOperationsChangeListener(OperationsChangeListener listener);
 
   /**
    * Remove the listener from the observers list.
@@ -143,26 +137,5 @@ public interface WebServiceDiscovererI
    * @param listener
    *          listener to be removed
    */
-  public default void removeOperationsChangeListener(
-      OperationsChangeListener listener)
-  {
-    serviceListeners.remove(listener);
-  }
-
-  /**
-   * Called whenever the list of operations changes. Notifies all listeners of
-   * the change to the operations list. Typically, should be called with an
-   * empty list at the beginning of the service discovery process and for the
-   * second time with the list of discovered operations after that.
-   * 
-   * @param list
-   *          new list of discovered operations
-   */
-  default void fireOperationsChanged(List<Operation> list)
-  {
-    for (var listener : serviceListeners)
-    {
-      listener.operationsChanged(this, list);
-    }
-  }
+  public void removeOperationsChangeListener(OperationsChangeListener listener);
 }
diff --git a/src/jalview/ws2/slivka/SlivkaWSDiscoverer.java b/src/jalview/ws2/slivka/SlivkaWSDiscoverer.java
index 4cbd1a2..f39559c 100644
--- a/src/jalview/ws2/slivka/SlivkaWSDiscoverer.java
+++ b/src/jalview/ws2/slivka/SlivkaWSDiscoverer.java
@@ -231,4 +231,26 @@ public class SlivkaWSDiscoverer implements WebServiceDiscovererI
     return "";
   }
 
+  
+  private OperationsChangeListenerList operationsChangeListeners =
+          new OperationsChangeListenerList(this);
+  
+  @Override
+  public void addOperationsChangeListener(OperationsChangeListener listener)
+  {
+    operationsChangeListeners.addListener(listener);
+  }
+
+  @Override
+  public void removeOperationsChangeListener(
+          OperationsChangeListener listener)
+  {
+     operationsChangeListeners.removeListener(listener);
+  }
+  
+  private void fireOperationsChanged(List<Operation> list)
+  {
+    operationsChangeListeners.fireOperationsChanged(list);
+  }
+
 }
-- 
1.7.10.2