[jboss-user] [JBoss Seam] - Re: Further extending an EntityHome

[mustaghattack]

Hi, about the EntityHome class I think it would be better to just pass the entity class as a parameter for the constructor, or at least to have a parameterized constructor.
I've done a quick performance test to see the reflection overhead :
with a Sun 1.6 JVM it's > 30.


  | package test.java;
  | 
  | import java.lang.reflect.ParameterizedType;
  | import java.lang.reflect.Type;
  | 
  | public class GuessParameterizePerformanceTest {
  | 	public static class GuessParam< E > {
  | 		private Class< E > entityClass;
  | 		
  | 		public GuessParam() {
  | 			getEntityClass();
  | 		}
  | 		
  | 		  public Class<E> getEntityClass()
  | 		   {
  | 		      if (entityClass==null)
  | 		      {
  | 		         Type type = getClass().getGenericSuperclass();
  | 		         if (type instanceof ParameterizedType)
  | 		         {
  | 		            ParameterizedType paramType = (ParameterizedType) type;
  | 		            entityClass = (Class<E>) paramType.getActualTypeArguments()[0];
  | 		         }
  | 		         else
  | 		         {
  | 		            throw new IllegalArgumentException("Could not guess entity class by reflection");
  | 		         }
  | 		      }
  | 		      return entityClass;
  | 		   }
  | 	}
  | 	
  | 	public static class DontGuessParam< E > {
  | 		private Class< E > entityClass;
  | 		
  | 		public DontGuessParam( Class< E > cls ) {
  | 			this.entityClass = cls;
  | 			getEntityClass();
  | 		}
  | 		
  | 		public Class< E > getEntityClass() {
  | 			return entityClass;
  | 		}
  | 	}
  | 	
  | 	public static class GuessParamChild extends GuessParam< String > {		
  | 	}
  | 	
  | 	public static class DontGuessParamChild extends DontGuessParam< String > {
  | 		public DontGuessParamChild() {
  | 			super( String.class );
  | 		}
  | 	}
  | 	
  | 	public static void main(String[] args) {
  | 		float avgGuess = 0, avgDontGuess = 0;
  | 		float nbLoop = 5, nbInstanciation = 1000000;
  | 		long time;
  | 		
  | 		for( long i = 0; i < nbLoop; i ++ ) {
  | 			time = System.currentTimeMillis();
  | 			for( long j = 0; j < nbInstanciation; j ++ ) {
  | 				GuessParamChild guess = new GuessParamChild();			
  | 			}
  | 			avgGuess += System.currentTimeMillis() - time;
  | 			
  | 			time = System.currentTimeMillis();
  | 			for( long j = 0; j < nbInstanciation; j ++ ) {
  | 				DontGuessParamChild dontGuess = new DontGuessParamChild();
  | 			}
  | 			avgDontGuess += System.currentTimeMillis() - time;
  | 		}
  | 		
  | 		System.out.println("avgGuess = " + (avgGuess / nbLoop));
  | 		System.out.println("avgDontGuess = " + (avgDontGuess / nbLoop));
  | 		System.out.println( "Guess overhead : " + ( avgGuess - avgDontGuess ) / avgDontGuess );
  | 	}
  | }
  | 

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