Java 8中通过多个匹配值获取列表的对象

Question

我正在尝试按最高值匹配进行规则过滤。

我有一个包含多个产品的销售，我必须对每个产品应用不同的规则。

获得此结果的最佳方法是什么？

List<Rule> rules = listOfRules();

String system = "MySystem1";

Map<Product, Rule> mapOfProductRule = new HashMap<Product, Rule>();

sale.getProducts().forEach(product -> {

    int points = 0;

    Rule matchedRule = null;

    for (Rule rule : rules) {

        if (system == rule.getSystem()) {

            int countMatchs = 0;

            if (sale.getValue1() == rule.getValue1()) countMatchs++;

            if (sale.getValue2() == rule.getValue2()) countMatchs++;

            if (product.getPvalue1() == rule.getPvalue1()) countMatchs++;

            if (product.getPvalue2() == rule.getPvalue2()) countMatchs++;

            if (countMatchs!= 0 && points < countMatchs)

            {

                points = countMatchs;

                matchedRule = rule;

            }

        }

    }

    mapOfProductRule.put(product, matchedRule);

});

return mapOfProductRule;

Answer 1

首先，我会将所有 4 if.. 移动到Rule类中的一个方法中public int getScore(Sale sale, Product product) {&nbsp; &nbsp; int count = 0;&nbsp; &nbsp; if (this.getValue1() == sale.getValue1()) count++;&nbsp; &nbsp; //...&nbsp; &nbsp; return count;}然后我会rules用Rule bestRule = rules.stream().max(Comparator.comparingInt(r -> r.getScore(sale, product)));