从多集中删除集合的引用

似乎multiset中应该有removalalloccuring(collection)(或类似的)方法。类似于 remove(Object,int) 和 removeAll(Collection) . 除此之外,实现其意图的最佳方法是什么?我写了一个小Junit驱动程序来演示:

/**
 * @see http://google-collections.googlecode.com/svn/trunk/javadoc/com/google/common/collect/Multiset.html
 * @see http://google-collections.googlecode.com/svn/trunk/javadoc/com/google/common/collect/HashMultiset.html  
 */
@Test
public void testBag() {
    Multiset<String> bag1 = HashMultiset.create();
    bag1.add("a", 2);
    bag1.add("b", 3);
    bag1.add("c", 3);

    logger.debug(bag1);
    Multiset<String> bag1Copy = HashMultiset.create(bag1);

    Multiset<String> bag2 = ImmutableMultiset.of("a","b","b","b","c","c");
    Multiset<String> expected = ImmutableMultiset.of("a","c");

    for( String el :  bag2.elementSet() ) {
        bag1.remove( el, bag2.count(el));
    } // end for

    Assert.assertEquals(expected, bag1);

    bag1Copy.removeAll(bag2);
    logger.debug( bag1Copy );
}

输出:

[b x 3, c x 3, a x 2]
[]

我在想,如果我不见了,可能会有一种方法,或者是一种比循环遍历要删除的集合更好的方法。另外请注意,我可以很容易地得到一个用例,其中要删除的集合是 List