[jboss-user] [JBoss Microcontainer Development] New message: "Re: Optimizing ScopeKey"

[Kabir Khan]

User development,

A new message was posted in the thread "Optimizing ScopeKey":

http://community.jboss.org/message/526058#526058

Author  : Kabir Khan
Profile : http://community.jboss.org/people/kabir.khan@jboss.com

Message:
--------------------------------------------------------------
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

--------------------------------------------------------------

To reply to this message visit the message page: http://community.jboss.org/message/526058#526058