[PATCH] Implement a noop clear() for Collections#EMPTY_LIST

[Mohamed Naufal]

Hi,

I see that this is applicable to EmptyMap and EmptySet as well, here's an
updated patch with clear() overridden for all 3 classes.

Thanks,
Naufal

On 23 May 2016 at 16:13, Paul Sandoz <paul.sandoz at oracle.com> wrote:

> Hi Naufal,
>
> Thanks for looking at this.
>
> For us to accept your patch (no matter how small) you need to become a
> contributor, which requires that you agree to the Oracle Contributor
> Agreement (OCA), see:
>
>   http://openjdk.java.net/contribute/
>
> Thanks,
> Paul.
>
> > On 22 May 2016, at 12:10, Mohamed Naufal <naufal11 at gmail.com> wrote:
> >
> > Hi,
> >
> > A call to clear() on Collections#EMPTY_LIST is currently redirected to
> > AbstractList#clear(), which performs a bunch of checks and creates a
> > ListItr object, all of which is unnecessary for an EmptyList.
> >
> > PFA a patch that implements a noop clear() for EmptyList.
> >
> > Thanks,
> > Naufal
> > <EmptyList_clear.diff>
>
>
-------------- next part --------------
# HG changeset patch
# User Mohamed Naufal <naufal11 at gmail.com>
# Date 1464424050 -19800
#      Sat May 28 13:57:30 2016 +0530
# Node ID 78c139550bfce1c1795dc5d7820766b95de19d2c
# Parent  bbc19b6de175e355d008d6b968183bd3c4edce55
Collections: Implement a noop clear() for EmptyList, EmptyMap and EmptySet

diff -r bbc19b6de175 -r 78c139550bfc src/java.base/share/classes/java/util/Collections.java
--- a/src/java.base/share/classes/java/util/Collections.java	Thu May 26 16:02:16 2016 +0000
+++ b/src/java.base/share/classes/java/util/Collections.java	Sat May 28 13:57:30 2016 +0530
@@ -4324,6 +4324,7 @@
 
         public int size() {return 0;}
         public boolean isEmpty() {return true;}
+        public void clear() {}
 
         public boolean contains(Object obj) {return false;}
         public boolean containsAll(Collection<?> c) { return c.isEmpty(); }
@@ -4447,6 +4448,7 @@
 
         public int size() {return 0;}
         public boolean isEmpty() {return true;}
+        public void clear() {}
 
         public boolean contains(Object obj) {return false;}
         public boolean containsAll(Collection<?> c) { return c.isEmpty(); }
@@ -4582,6 +4584,7 @@
 
         public int size()                          {return 0;}
         public boolean isEmpty()                   {return true;}
+        public void clear()                        {}
         public boolean containsKey(Object key)     {return false;}
         public boolean containsValue(Object value) {return false;}
         public V get(Object key)                   {return null;}