过滤集合Collection

文章目录

//1.0 直接遍历过滤
	Iterator<Integer> itr = list.iterator();
	while(itr.hasNext()) {
		int i = itr.next();
		if (i > 5) { // filter all ints bigger than 5
			itr.remove();
		}
	}




//2.0通用方法
// filter
interface Predicate<T>{
	boolean test(T o);
}
class Filter{
	public static <T> void filter(Collection<T> c,Predicate<T> p) {
		if(null != c && null != p){
			Iterator<T> itr = c.iterator();
			while(itr.hasNext()){
				T obj = itr.next();
				if(!p.test(obj)){
					itr.remove();
				}
			}
		}
	}
}


public class SimpleTest {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		SimpleTest sdt = new SimpleTest();
		
		sdt.filterCollection();
	}
	
	private void filterCollection() {
		Integer[] iarr = {1,2,3,8};
		List<Integer> list = new ArrayList<Integer>(Arrays.asList(iarr));
		Filter.filter(list , new Predicate<Integer>() {

			@Override
			public boolean test(Integer o) {
				// TODO Auto-generated method stub
				return o.intValue() <= 5;
			}
		});
		System.out.println(Arrays.toString(iarr));
		System.out.println(list);
	}
	
	/*
	* output:
	* [1, 2, 3, 8]
	* [1, 2, 3]
	*/
}