Registration to remove state.registeredEventListeners (fixes #9634) (#10130)

This changes SharedState.registeredEventListeners to be a Map that keeps track of how many listeners of each type have been added, and handles unregistering of such listeners correctly.

2 files changed, 26 insertions, 12 deletions

diff --git a/shared/src/main/java/com/vaadin/shared/communication/SharedState.java b/shared/src/main/java/com/vaadin/shared/communication/SharedState.java
index 6b9c1045c5..57ad67a0d7 100644
--- a/shared/src/main/java/com/vaadin/shared/communication/SharedState.java
+++ b/shared/src/main/java/com/vaadin/shared/communication/SharedState.java
@@ -19,7 +19,6 @@ package com.vaadin.shared.communication;
 import java.io.Serializable;
 import java.util.HashMap;
 import java.util.Map;
-import java.util.Set;
 
 import com.vaadin.shared.Connector;
 import com.vaadin.shared.annotations.NoLayout;
@@ -62,10 +61,14 @@ public class SharedState implements Serializable {
     public Map<String, URLReference> resources = new HashMap<>();
 
     public boolean enabled = true;
+
     /**
-     * A set of event identifiers with registered listeners.
+     * A Map of event identifiers with registered listeners, {@code key} is
+     * event identifier, {@code value} is the listeners count.
+     * 
+     * @since
      */
     @NoLayout
-    public Set<String> registeredEventListeners = null;
+    public Map<String, Integer> registeredEventListeners;
 
 }
diff --git a/shared/src/main/java/com/vaadin/shared/ui/ComponentStateUtil.java b/shared/src/main/java/com/vaadin/shared/ui/ComponentStateUtil.java
index 0ef247353b..a2f6618b9e 100644
--- a/shared/src/main/java/com/vaadin/shared/ui/ComponentStateUtil.java
+++ b/shared/src/main/java/com/vaadin/shared/ui/ComponentStateUtil.java
@@ -16,7 +16,7 @@
 package com.vaadin.shared.ui;
 
 import java.io.Serializable;
-import java.util.HashSet;
+import java.util.HashMap;
 
 import com.vaadin.shared.AbstractComponentState;
 import com.vaadin.shared.Registration;
@@ -67,12 +67,19 @@ public final class ComponentStateUtil implements Serializable {
     @Deprecated
     public static final void removeRegisteredEventListener(SharedState state,
             String eventIdentifier) {
-        if (state.registeredEventListeners == null) {
-            return;
-        }
-        state.registeredEventListeners.remove(eventIdentifier);
-        if (state.registeredEventListeners.size() == 0) {
-            state.registeredEventListeners = null;
+        if (state.registeredEventListeners != null) {
+            Integer count = state.registeredEventListeners.get(eventIdentifier);
+            if (count != null) {
+                if (count > 1) {
+                    state.registeredEventListeners.put(eventIdentifier,
+                            count - 1);
+                } else {
+                    state.registeredEventListeners.remove(eventIdentifier);
+                    if (state.registeredEventListeners.isEmpty()) {
+                        state.registeredEventListeners = null;
+                    }
+                }
+            }
         }
     }
 
@@ -87,9 +94,13 @@ public final class ComponentStateUtil implements Serializable {
     public static final Registration addRegisteredEventListener(
             SharedState state, String eventListenerId) {
         if (state.registeredEventListeners == null) {
-            state.registeredEventListeners = new HashSet<>();
+            state.registeredEventListeners = new HashMap<>();
+        }
+        Integer count = state.registeredEventListeners.get(eventListenerId);
+        if (count == null) {
+            count = 0;
         }
-        state.registeredEventListeners.add(eventListenerId);
+        state.registeredEventListeners.put(eventListenerId, count + 1);
         return () -> removeRegisteredEventListener(state, eventListenerId);
     }
 }