Java——反向列表的实现

反向列表

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;

public class ReverseList<T> extends ArrayList<T>{

	private static final long serialVersionUID = 1L;
	
	public ReverseList(Collection<T> c){ super(c);}
	
	public Iterable<T> reversed(){
		return new Iterable<T>() {

			@Override
			public Iterator<T> iterator() {
				return new Iterator<T>() {
					private int index = size()-1;
					
					@Override
					public boolean hasNext() {	
						return index>=0;
					}

					@Override
					public T next() {
						return get(index--);
					}
				};
			}
		};
	}
}

测试代码

import java.util.ArrayList;
import java.util.Iterator;

public class ReverseListTest {
	public static void main(String[] args) {
		ArrayList<String> wl = new ArrayList<String>();
		for(int i = 0; i<10; i++){
			wl.add("str"+i);
		}
		ReverseList<String> rl = new ReverseList<String>(wl);
		Iterator<String> itr = rl.reversed().iterator();
		while(itr.hasNext()){
			System.out.println(itr.next());
		}
	}

}