OPEN - issue BATCH-865: CompositeItemProcessor should handle null properly

http://jira.springframework.org/browse/BATCH-865

If any processor returns null, then the composite will now return null.

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/CompositeItemProcessor.java

@@ -25,6 +25,9 @@ public class CompositeItemProcessor<I, O> implements ItemProcessor<I, O>, Initia
 		Object result = item;
 	
 		for(ItemProcessor transformer: itemProcessors){
+			if(result == null){
+				return null;
+			}
 			result = transformer.process(result);
 		}
 		return (O) result;