More efficient allocation of array in MessageDispatcher.cast() (https…

…://issues.redhat.com/browse/JGRP-2855)

src/org/jgroups/blocks/MessageDispatcher.java

@@ -11,7 +11,10 @@
 import org.jgroups.util.*;
 
 import java.io.*;
-import java.util.*;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeoutException;
 import java.util.stream.Stream;
@@ -259,11 +262,12 @@ protected <T> GroupRequest<T> cast(final Collection<Address> dests, Message msg,
 
         List<Address> real_dests;
         // we need to clone because we don't want to modify the original
-        if(dests != null)
-            real_dests=dests.stream().filter(dest -> dest instanceof SiteAddress || this.members.contains(dest))
-              .collect(ArrayList::new, (list,dest) -> {if(!list.contains(dest)) list.add(dest);}, (l,r) -> {});
+        if(dests != null) {
+            real_dests=new FastArray<>(dests);
+            real_dests.removeIf(addr -> !this.members.contains(addr) && !(addr instanceof SiteAddress));
+        }
         else
-            real_dests=new ArrayList<>(members);
+            real_dests=new FastArray<>(members);
 
         // Remove the local member from the target destination set if we should not deliver our own message
         JChannel tmp=channel;
@@ -292,7 +296,6 @@ protected <T> GroupRequest<T> cast(final Collection<Address> dests, Message msg,
     }
 
 
-
     /**
      * Sends a unicast message and - depending on the options - returns a result
      * @param msg the payload to send

src/org/jgroups/util/FastArray.java

@@ -32,6 +32,11 @@ public FastArray(T[] elements, int index) {
         this.size=count();
     }
 
+    public FastArray(Collection<? extends T> c) {
+        this(c != null? c.size() : 16);
+        addAll(c);
+    }
+
     public int          capacity()        {return elements.length;}
     public int          index()           {return index;}
     public int          size()            {return size;}

tests/perf/org/jgroups/tests/perf/UPerf.java

@@ -502,7 +502,7 @@ private class Invoker implements Runnable {
         private final List<Address>  dests=new ArrayList<>();
         private final CountDownLatch latch;
         private final AverageMinMax  avg_gets=new AverageMinMax(), avg_puts=new AverageMinMax(); // in ns
-        private final List<Address>  targets=new ArrayList<>(anycast_count);
+        private final List<Address>  targets=new FastArray<>(anycast_count);
         private volatile boolean     running=true;