发现CollectionUtils的bug了

	public static void main(String[] args) {
		Collection<String> collection = new ArrayList<String>();
		Collection<String> remove = new ArrayList<String>();
		Collection<String> retain = new ArrayList<String>();
		collection.add(new String("A"));
		collection.add(new String("B"));
		collection.add(new String("C"));
		collection.add(new String("D"));
		
		remove.add(new String("A"));
		remove.add(new String("B"));
		remove.add(new String("C"));
		
		retain.add(new String("A"));
		retain.add(new String("D"));
		retain.add(new String("E"));
		
		Collection<String> result = (Collection<String>)CollectionUtils.removeAll(collection, remove);
		System.out.println(result.size());
		for (String string : result) {
			System.out.print(string);
			System.out.print(",");
		}
		System.out.println();
		result = (Collection<String>)CollectionUtils.retainAll(collection, retain);
		System.out.println(result.size());
		for (String string : result) {
			System.out.print(string);
			System.out.print(",");
		}
}

 

 输出结果：

 

3
A,B,C,
2
A,D,

 

实际上removeAll 应该返回一个包含字符串 D 的Collection才对，这里应该是CollectionUtils的一个bug 

 

 

 

——————————————————————————————————————————————————

 

评论

1 楼 zhuuk999 2009-02-23  

不是BUG吧，doc上写的很清楚a Collection containing all the elements of collection except any elements that also occur in remove.
要返回D 的Collectiony应该用subtract才对