Request for review : 7121314 : Behavior mismatch between AbstractCollection.toArray(T[] ) and its spec

[David Holmes]

Here's a simple testcase that seems to work.

David

On 9/03/2012 7:53 PM, David Holmes wrote:
> Hi Sean,
>
> That seems to implement the required semantics.
>
> Minor style nit: }else{ -> } else {
>
> Not sure about the testcase ... Can size() not remove some elements
> directly but return the original size?
>
> David


/*
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/*
  * @test
  * @bug 7121314
  * @summary return the original array if the collection shrinks and 
will fit
  */

import java.util.*;
import java.util.concurrent.*;

public class ToArray {

   static final int excess = 2;
   static final String[] keys = { "1", "2", "3", "4", "5" };
   static final Object[] vals = { new Object(), new Object(), new Object(),
                                  new Object(), new Object()
   };

   static class TConcurrentHashMap<K, V> extends ConcurrentHashMap<K, V> {
     public int size() {
       int oldsize = super.size();
       remove(keys[0]);
       remove(keys[1]);
       check(super.size() == oldsize-2);
       return oldsize;
     }
   }

   private static void realMain(String[] args) {
     TConcurrentHashMap<String, Object> map = new TConcurrentHashMap<>();
     for (int i = 0; i < keys.length; i++)
       map.put(keys[i], vals[i]);

     Object[] a = new Object[keys.length-1]; // appears too small
     Object[] res = map.values().toArray(a);
     check( res == a);
     pass();
   }

   //--------------------- Infrastructure ---------------------------
     static volatile int passed = 0, failed = 0;
   static void pass() { passed++; }
   static void fail() { failed++; Thread.dumpStack(); }
   static void fail(String msg) { System.out.println(msg); fail(); }
   static void unexpected(Throwable t) { failed++; t.printStackTrace(); }
   static void check(boolean cond) { if (cond) pass(); else fail(); }
   static void equal(Object x, Object y) {
     if (x == null ? y == null : x.equals(y)) pass();
     else {System.out.println(x + " not equal to " + y); fail(); }}

   public static void main(String[] args) throws Throwable {
     try { realMain(args); } catch (Throwable t) { unexpected(t); }

     System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
     if (failed > 0) throw new Exception("Some tests failed");
   }
}