Optimizing ScopeKey

[kabirkhan]

Continued from http://community.jboss.org/message/525925#525925

1001 puts into BasicMetaDataRepository.retrievals results in 499500 UnmodifiableScopeKey calls. That is the sum of all numbers from 1 to 999, so it seems like the hashing is not working properly and that we iterate over all entries when doing a put to check if they exist.

[kabirkhan]

Yes, the hashing function is broken

   int iterations = 15;

   public void testScopeKeyHashing()
   {
      List<ScopeKey> scopes = createScopeKeys();
      List<ScopeKey> lockedScopes = createFroxenScopeKeys(scopes);
      
      assertSame(scopes.size(), lockedScopes.size());
      
      for (int i = 0 ; i < iterations ; i++)
      {
         assertTrue(scopes.get(i).equals(lockedScopes.get(i)));
         assertTrue(lockedScopes.get(i).equals(scopes.get(i)));
         assertEquals(scopes.get(i).hashCode(), lockedScopes.get(i).hashCode());
         System.out.println(scopes.get(i).hashCode() + "  " + scopes.get(i));
         assertNotSame(scopes.get(i), lockedScopes.get(i));
      }
   }
   
   private List<ScopeKey> createScopeKeys()
   {
      List<ScopeKey> keys = new ArrayList<ScopeKey>();
      for (int i = 0 ; i < iterations ; i++)
      {
         ScopeKey scopeKey = ScopeKey.DEFAULT_SCOPE.clone();
         scopeKey.addScope(CommonLevels.INSTANCE, "Bean" + i + Math.random() + 10000);
         scopeKey.addScope(CommonLevels.CLASS, Object.class.getName());
         keys.add(scopeKey);
      }
      return keys;
   }

 
   private List<ScopeKey> createFroxenScopeKeys(List<ScopeKey> scopes)
   {
      List<ScopeKey> frozens = new ArrayList<ScopeKey>();
      for (ScopeKey key : scopes)
      {
         ScopeKey frozen = key.getOptimizedKey();
         frozen.freeze();
         frozens.add(frozen);
      }
      return frozens;
   }

gives the same value 3400

3400  [JVM=THIS, APPLICATION=xyz0, CLASS=java.lang.Object, INSTANCE=Bean00.724748247059574310000]

3400  [JVM=THIS, APPLICATION=xyz1, CLASS=java.lang.Object, INSTANCE=Bean10.821575642383577510000]

3400  [JVM=THIS, APPLICATION=xyz2, CLASS=java.lang.Object, INSTANCE=Bean20.3658072070977499410000]

3400  [JVM=THIS, APPLICATION=xyz3, CLASS=java.lang.Object, INSTANCE=Bean30.17405710442802047

10000]

3400  [JVM=THIS, APPLICATION=xyz4, CLASS=java.lang.Object, INSTANCE=Bean40.328947822381441710000]

3400  [JVM=THIS, APPLICATION=xyz5, CLASS=java.lang.Object, INSTANCE=Bean50.853785127372253610000]

3400  [JVM=THIS, APPLICATION=xyz6, CLASS=java.lang.Object, INSTANCE=Bean60.308661441767311610000]

3400  [JVM=THIS, APPLICATION=xyz7, CLASS=java.lang.Object, INSTANCE=Bean70.3214439497564738310000]

3400  [JVM=THIS, APPLICATION=xyz8, CLASS=java.lang.Object, INSTANCE=Bean80.73783778624132910000]

3400  [JVM=THIS, APPLICATION=xyz9, CLASS=java.lang.Object, INSTANCE=Bean90.301807484250228210000]

3400  [JVM=THIS, APPLICATION=xyz10, CLASS=java.lang.Object, INSTANCE=Bean100.4474778106602691510000]

3400  [JVM=THIS, APPLICATION=xyz11, CLASS=java.lang.Object, INSTANCE=Bean110.1197707023336379610000]

3400  [JVM=THIS, APPLICATION=xyz12, CLASS=java.lang.Object, INSTANCE=Bean120.313969251914117510000]

3400  [JVM=THIS, APPLICATION=xyz13, CLASS=java.lang.Object, INSTANCE=Bean130.609491494722042910000]

3400  [JVM=THIS, APPLICATION=xyz14, CLASS=java.lang.Object, INSTANCE=Bean140.713736711778368310000]

That must be the real problem, causing UnmodifiableScopeKey.equals()->ScopeKey.getArray()->Collection.toArray() to be called too many times. Looking at the ScopeKey.computeHashCode function it only takes the levels into account:

   protected static int computeHashCode(Iterable<Scope> scopeCollection)
   {
      int hashCode = 0;
      for (Scope scope : scopeCollection)
         hashCode += scope.getScopeLevel().hashCode();
      return hashCode;
   }
 

I've rewritten this to hash properly, which makes the retrievals map behave like a map, giving less ScopeKey.equals() hits

Scope constructor:

   public Scope(ScopeLevel level, Object qualifier)
   {
      if (level == null)
         throw new IllegalArgumentException("Null level");
      if (qualifier == null)
         throw new IllegalArgumentException("Null qualifier");
      
      this.level = level;
      this.qualifier = qualifier;

      int hash = 17;
      hash = 31 * hash + level.hashCode();
      hash = 31 * hash + qualifier.hashCode();
      hashcode = hash;
   }

   protected static int computeHashCode(Iterable<Scope> scopeCollection)
   {
      int hashCode = 0;
      for (Scope scope : scopeCollection)
         //hashCode += scope.getScopeLevel().hashCode();
         hashCode += scope.hashCode();
      return hashCode;
   }

I'll add a test and commit against https://jira.jboss.org/jira/browse/JBMDR-65 and then see what this does to AS boot times