org.apache.commons.collections4.Bag<E>

新的接口被添加到支持bag。 Bag接口定义了一个集合，它可以计算一个对象出现在集合中的次数。

public class BagTester {
    public static void main(String[] args) {
        //org.apache.commons.collections4.Bag<E>接口继承自java.util.Collection
        Bag<String> bag = new HashBag<String>();
        bag.add("a",2);
        bag.add("a");
        bag.add("a");
        bag.add("a");
        bag.add("b");
        bag.add("d",3);
        System.out.println(bag);
        System.out.println("a出现了:"+bag.getCount("a")+"次");
        System.out.println("b出现了:"+bag.getCount("b")+"次");
        System.out.println("c出现了:"+bag.getCount("c")+"次");
        System.out.println("b出现了:"+bag.getCount("d")+"次");
        System.out.println("Set<E> uniqueSet():"+bag.uniqueSet());
        System.out.println("删除d:"+bag.remove("d"));
        System.out.println("删除后:"+bag);
        System.out.println("删除1个a:"+bag.remove("a",1));
        System.out.println("删除后"+bag);
        System.out.println(bag.containsAll(Arrays.asList("a","b")));
        System.out.println(bag.containsAll(Arrays.asList("a","b","c")));
        System.out.println(bag.containsAll(Arrays.asList("4","1")));
    }
}

结果:

[5:a,1:b,3:d]
a出现了:5次
b出现了:1次
c出现了:0次
b出现了:3次
Set<E> uniqueSet():[a, b, d]
删除d:true
删除后:[5:a,1:b]
删除1个a:true
删除后[4:a,1:b]
true
false
false
org.apache.commons.collections4.bag.AbstractMapBag$BagIterator@66d3c617

结束