Question

UI上有4个不同的用户输入字段，如Multiselect Dropdown。用户可以提供输入字段的不同组合以缩小结果集。（从多选选项中选择所有/几个选项）。

示例 2多选选项

多选选项A包含元素{＆＃34; 10xyz1＆＃34;，＆＃34; 11xyz1＆＃34;，...}，

多选选项B包含元素{＆＃34; xyz101＆＃34;，＆＃34; abc111＆＃34;，...}

2 ^ 2可能的输入组合（提示：二进制真值表）：

1）从Multiselect选项A＆amp;＆amp;中选择所有元素。从Multiselect选项B中选择所有元素，

2）从Multiselect选项A＆amp;＆amp;中选择所有元素。从Multiselect Option B中选择几个元素，

3）从Multiselect选项A＆amp;＆amp;和从Multiselect选项B中选择所有元素，

4）从Multiselect选项A＆amp;＆amp; amp;从Multiselect Option B中选择几个元素

注意：必须从任一选项中选择至少一个元素

我使用了if else语句来实现我的逻辑（我为每个可能的选择分别设置了mongo集合，4个字段，16种可能的组合，所以16个mongo集合），但问题是代码看起来非常丑陋很多如果在UI中添加了另外一个字段，那么if-else语句就会结束，那么我必须检查添加其他条件语句。

目前条件if-else语句的数量是2 ^ N（其中N是Multiselect下拉输入字段的数量）。

代码段：

    private void constructQuery(MongoQuEry query, AnalysisFilter filter)
    {
    query.addFilterField("_id.operator", MongoQuEry.OP_EQUALS, "alpha");

    query.addFilterField("_id.month_year", MongoQuEry.OP_IN, getListOfMonthYear(filter));


    String collectionName;
    if (filter.getAllMarket() && filter.getAllCmts() && filter.getAllNode() && filter.getAllPackage()) {
        collectionName = CollectionNames.ME_USAGE_MONTH_YEAR.toString();
    } else if (filter.getAllMarket() && filter.getAllCmts() && filter.getAllNode()) {
        collectionName = CollectionNames.ME_USAGE_MONTH_YEAR_PACKAGE.toString();
        query.addFilterField("_id.package", MongoQuEry.OP_IN, filter.getSubscriberPackage());
    } else if (filter.getAllMarket() && filter.getAllCmts() && filter.getAllPackage()) {
        collectionName = CollectionNames.ME_USAGE_MONTH_YEAR_NODE.toString();
        query.addFilterField("_id.node", MongoQuEry.OP_IN, filter.getNode());
    } else if (filter.getAllMarket() && filter.getAllCmts()) {
        collectionName = CollectionNames.ME_USAGE_MONTH_YEAR_NODE_PACKAGE.toString();
        query.addFilterField("_id.node", MongoQuEry.OP_IN, filter.getNode());
        query.addFilterField("_id.package", MongoQuEry.OP_IN, filter.getSubscriberPackage());
    } else if (filter.getAllMarket() && filter.getAllNode() && filter.getAllPackage()) {
        collectionName = CollectionNames.ME_USAGE_MONTH_YEAR_CMTS.toString();
        query.addFilterField("_id.cmts", MongoQuEry.OP_IN, filter.getCmts());
    } else if (filter.getAllMarket() && filter.getAllNode()) {
        collectionName = CollectionNames.ME_USAGE_MONTH_YEAR_CMTS_PACKAGE.toString();
        query.addFilterField("_id.cmts", MongoQuEry.OP_IN, filter.getCmts());
        query.addFilterField("_id.package", MongoQuEry.OP_IN, filter.getSubscriberPackage());
    } else if (filter.getAllMarket() && filter.getAllPackage()) {
        collectionName = CollectionNames.ME_USAGE_MONTH_YEAR_CMTS_NODE.toString();
        query.addFilterField("_id.cmts", MongoQuEry.OP_IN, filter.getCmts());
        query.addFilterField("_id.node", MongoQuEry.OP_IN, filter.getNode());
    } else if (filter.getAllMarket()) {
        collectionName = CollectionNames.ME_USAGE_MONTH_YEAR_CMTS_NODE_PACKAGE.toString();
        query.addFilterField("_id.cmts", MongoQuEry.OP_IN, filter.getCmts());
        query.addFilterField("_id.node", MongoQuEry.OP_IN, filter.getNode());
        query.addFilterField("_id.package", MongoQuEry.OP_IN, filter.getSubscriberPackage());
    } else if (filter.getAllCmts() && filter.getAllNode() && filter.getAllPackage()) {
        collectionName = CollectionNames.ME_USAGE_MONTH_YEAR_MARKET.toString();
        query.addFilterField("_id.market", MongoQuEry.OP_IN, filter.getMarket());
    } else if (filter.getAllCmts() && filter.getAllNode()) {
        collectionName = CollectionNames.ME_USAGE_MONTH_YEAR_MARKET_PACKAGE.toString();
        query.addFilterField("_id.market", MongoQuEry.OP_IN, filter.getMarket());
        query.addFilterField("_id.package", MongoQuEry.OP_IN, filter.getSubscriberPackage());
    } else if (filter.getAllCmts() && filter.getAllPackage()) {
        collectionName = CollectionNames.ME_USAGE_MONTH_YEAR_MARKET_NODE.toString();
        query.addFilterField("_id.market", MongoQuEry.OP_IN, filter.getMarket());
        query.addFilterField("_id.node", MongoQuEry.OP_IN, filter.getNode());
    } else if (filter.getAllCmts()) {
        collectionName = CollectionNames.ME_USAGE_MONTH_YEAR_MARKET_NODE_PACKAGE.toString();
        query.addFilterField("_id.market", MongoQuEry.OP_IN, filter.getMarket());
        query.addFilterField("_id.node", MongoQuEry.OP_IN, filter.getNode());
        query.addFilterField("_id.package", MongoQuEry.OP_IN, filter.getSubscriberPackage());
    } else if (filter.getAllNode() && filter.getAllPackage()) {
        collectionName = CollectionNames.ME_USAGE_MONTH_YEAR_MARKET_CMTS.toString();
        query.addFilterField("_id.market", MongoQuEry.OP_IN, filter.getMarket());
        query.addFilterField("_id.cmts", MongoQuEry.OP_IN, filter.getCmts());
    } else if (filter.getAllNode()) {
        collectionName = CollectionNames.ME_USAGE_MONTH_YEAR_MARKET_CMTS_PACKAGE.toString();
        query.addFilterField("_id.market", MongoQuEry.OP_IN, filter.getMarket());
        query.addFilterField("_id.cmts", MongoQuEry.OP_IN, filter.getCmts());
        query.addFilterField("_id.package", MongoQuEry.OP_IN, filter.getSubscriberPackage());
    } else if (filter.getAllPackage()) {
        collectionName = CollectionNames.ME_USAGE_MONTH_YEAR_MARKET_CMTS_NODE.toString();
        query.addFilterField("_id.market", MongoQuEry.OP_IN, filter.getMarket());
        query.addFilterField("_id.cmts", MongoQuEry.OP_IN, filter.getCmts());
        query.addFilterField("_id.node", MongoQuEry.OP_IN, filter.getNode());
    } else {
        collectionName = CollectionNames.ME_USAGE_MONTH_YEAR_MARKET_CMTS_NODE_PACKAGE.toString();
        query.addFilterField("_id.market", MongoQuEry.OP_IN, filter.getMarket());
        query.addFilterField("_id.cmts", MongoQuEry.OP_IN, filter.getCmts());
        query.addFilterField("_id.node", MongoQuEry.OP_IN, filter.getNode());
        query.addFilterField("_id.package", MongoQuEry.OP_IN, filter.getSubscriberPackage());
    }


    query.setCollection(collectionName);
    query.addGroupByFields("_id.operator", "_id.month_year");
    query.addAliasAggregateField("count", MongoQuEry.AGGR_SUM, "subscriber_count");

    int order = MongoQuEry.ORDER_ASC;
    query.addOrderByFields(order, "_id.month_year");

}

Answer 1

您可以通过对常见条件进行分组来创建决策树，例如，如果每次A为真，您都希望执行method1（），而不是在每个＆＃39;上编写此行代码，如果＆＃39 ;如果A为真，你可以先检查A是否为真，然后执行这个公共代码块，然后检查其他条件，如：

而不是写作：

if(a && b) {
     example.method1();
     example.method2();
     // more code 1
} else if(a && !b) {
     example.method1();
     // more code 2
} else if(!a && b) {
     example.method2();
     // more code 3
} else if(!a && !b) {
     // more code 4
}

你可以写：

if(a) {
     example.method1();
     if(b) {
          example.method2();
          // more code 1
     } else {
          // more code 2
     }
} else {
     if(b) {
          example.method2();
          // more code 3
     } else {
          // more code 4
     }
}

Answer 2

您的集合名称似乎有一个基于过滤器字段的模式，如果是这种方法可能有效。

Object marketFilter = filter.getAllMarket();
Object cmtsFilter = filter.getAllCmts();
Object packageFilter = filter.getAllPackage();
Object nodeFilter = filter.getAllNodes();


if(marketFilter != null){
    query.addFilterField("_id.market", MongoQuEry.OP_IN, filter.getMarket());
}
.
.
. upto filter N

String collectionName = getCollectionName(marketFilter, ... filter N)

/* 
 create a function getCollectionName(filter1, ... filterN)   
  in this function you can generate collection name by checking which 
  filters are not null.
*/

注意： - 只有当您的集合名称基于过滤器时，此方法才有效。

Answer 3

switch case或IIf表达怎么样？

https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/switch

https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/conditional-operator

switch case会更清晰，并将if-else内容分成多个函数：

void FunctionName()
{
        collectionName = CollectionNames.ME_USAGE_MONTH_YEAR_NODE_PACKAGE.toString();
        query.addFilterField("_id.node", MongoQuEry.OP_IN, filter.getNode());
        query.addFilterField("_id.package", MongoQuEry.OP_IN, 
        filter.getSubscriberPackage());
}

替代if-else语句或更好的方法

3 个答案: