From 0e1baccf4b9f9796b26257e79eaa08c1b1a64568 Mon Sep 17 00:00:00 2001
From: Michael Bayne <mdb@samskivert.com>
Date: Fri, 8 Apr 2011 17:48:07 -0700
Subject: [PATCH] Allow duplicate checking to be disabled for performance
 reasons. The profiler has spoken.

---
 .../com/samskivert/util/ObserverList.java     | 19 ++++++++++++++-----
 .../com/samskivert/util/WeakObserverList.java |  6 ++++++
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/src/main/java/com/samskivert/util/ObserverList.java b/src/main/java/com/samskivert/util/ObserverList.java
index a5f754d8..b7d015ef 100644
--- a/src/main/java/com/samskivert/util/ObserverList.java
+++ b/src/main/java/com/samskivert/util/ObserverList.java
@@ -177,6 +177,12 @@ public abstract class ObserverList<T>
      */
     public abstract void clear ();
 
+    /**
+     * Configures this observer list to check duplicates when adding observers, or not. By default
+     * duplicates are checked, but for performance reasons, one may wish to disable this check.
+     */
+    public abstract ObserverList setCheckDuplicates (boolean checkDuplicates);
+
     /**
      * Returns true if this list has no observers, false otherwise.
      */
@@ -194,14 +200,14 @@ public abstract class ObserverList<T>
 
         @Override public boolean add (int index, T element) {
             if (element == null) { throw new NullPointerException("Null observers not allowed."); }
-            if (isDuplicate(element)) { return false; }
+            if (_checkDups && isDuplicate(element)) { return false; }
             _list.add(index, element);
             return true;
         }
 
         @Override public boolean add (T element) {
             if (element == null) { throw new NullPointerException("Null observers not allowed."); }
-            if (isDuplicate(element)) { return false; }
+            if (_checkDups && isDuplicate(element)) { return false; }
             _list.add(element);
             return true;
         }
@@ -249,6 +255,11 @@ public abstract class ObserverList<T>
             _list.clear();
         }
 
+        @Override public ObserverList setCheckDuplicates (boolean checkDuplicates) {
+            _checkDups = checkDuplicates;
+            return this;
+        }
+
         /** Used to determine whether an element is in the list. */
         protected int indexOf (T element) {
             for (int ii = 0, ll = _list.size(); ii < ll; ii++) {
@@ -269,11 +280,9 @@ public abstract class ObserverList<T>
             return false;
         }
 
-        /** The notification policy. */
         protected Policy _policy;
-
-        /** Our list of observers. */
         protected List<T> _list;
+        protected boolean _checkDups = true;
     }
 
     /**
diff --git a/src/main/java/com/samskivert/util/WeakObserverList.java b/src/main/java/com/samskivert/util/WeakObserverList.java
index 0eadf00b..2aa1be67 100644
--- a/src/main/java/com/samskivert/util/WeakObserverList.java
+++ b/src/main/java/com/samskivert/util/WeakObserverList.java
@@ -68,6 +68,12 @@ public class WeakObserverList<T> extends ObserverList<T>
         _delegate.clear();
     }
 
+    @Override public WeakObserverList setCheckDuplicates (boolean checkDuplicates)
+    {
+        _delegate.setCheckDuplicates(checkDuplicates);
+        return this;
+    }
+
     /**
      * Removes all garbage-collected observers from the list.
      */