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				Experience
          To know how dose List.remove(Object) work, I do many test sample. But I still feel not very realizing. Finally, I?took a look at?souce code, and then I knew everything!
          public?boolean?remove(Object?o)?{
          ????          if?(o?==?null)?{
          ????????????          for?(int?index?=?0;?index?<?size;?index++)
          ????????          if?(elementData[index]?==?null)?{
          ????????????fastRemove(index);
          ????????????          return?true;
          ????????}
          ????}          ?else?{
          ????????          for?(int?index?=?0;?index?<?size;?index++)
          ????????          if?(o.equals(elementData[index]))?{
          ????????????fastRemove(index);
          ????????????          return?true;
          ????????}
          ????????}
          ????          return?false;
          ????}
          1. List store very object's reference but object's own.
          2. remove(Object) will remove the first reference in List which refer to?the object
          3. If you want to change an object to a new index: back up it--> remove it--> re-add it

          Experience
          I create a class to handle something annotated by Annotations. But it doesn't work. I found out it is returned false by Class.getMethod().isAnnotationPresent(Todo.class). Finally, I got the reason by reading source code.
          public?enum?RetentionPolicy?{
          ????          /**
          ?????*?Annotations?are?to?be?discarded?by?the?compiler.
          ?????          */
          ????SOURCE,

          ????          /**
          ?????*?Annotations?are?to?be?recorded?in?the?class?file?by?the?compiler
          ?????*?but?need?not?be?retained?by?the?VM?at?run?time.??This?is?the?default
          ?????*?behavior.
          ?????          */
          ????CLASS,

          ????          /**
          ?????*?Annotations?are?to?be?recorded?in?the?class?file?by?the?compiler?and
          ?????*?retained?by?the?VM?at?run?time,?so?they?may?be?read?reflectively.
          ?????*
          ?????*?          @see?java.lang.reflect.AnnotatedElement
          ?????          */
          ????RUNTIME
          }

          

	
          posted on 2006-08-03 18:43 Jcat 閱讀(343) 評論(0)  編輯  收藏  所屬分類: Java 
          

          







          
	    
    




          








          

				

          



    







          
        
	




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