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) {

    int count = 0;

    if (this.getValue1() == sale.getValue1()) count++;

    //...

    return count;

}

然后我会rules用

Rule bestRule = rules.stream().max(Comparator.comparingInt(r -> r.getScore(sale, product)));