KChain

---

     

English | 中文

🔩 KChain, a flexible and configurable chain.

---

What is the problem

Sometimes, we will face a situations that we need to check various properties set such as Map<String,Object> or Entity entities ( named it as properties set).

Obviously, there will be one or more different verification rules for different properties.

So, it is necessary to have a chain structure to solve those problems.

KChain is an implementation to solve these problems.

The following two dimensions are usually considered:

Check Properties

• For a single properties set, such as Map<String,Object>

​ It needs to check whether its different properties match one or more rules.

​ For example, the value of the key calledname in a Map<String,Object> can not be empty.

• For batch of perperties set , such as List<User>

​ It is necessary to check whether they meet certain rules with each other.

​ For example, such as the same name of User can not exist in the batch of User set.

Rule Strategy

• Fail fast

  When one of the rule conditions is not met, return directly.

• Full check

  Running all the verification rules, verify all the rule items for its perperties.

---

How to solve it

There are some components which play an important role in KChain.

• ChainContext

  The context for the chain which can hold the information you wanna use in the whole chain life circle. Build in the cache and inheritable cache expired in the current chain test life circle. Such as some global parameters or special symbol.

• DataWrapper

  Wrapping the properties set and the Rulecontext together.

• RuleContext

  It is used to store the check result and the return flag bit of Predicate based on different check strategies.

• Rule

  It contains some rules for checking.

  There are three built-in rules for now:

  • testNotEmpty，whether the perperty value is empty based on the rule.

  • testInCases，whether the perperty value is in the given collection ( contains).

  • testOnCustomized，the fully customized implementation rule extension.

• RuleStrategy

  The check strategy.

  • FULL_CHECK

  • FAIL_FAST

    It is usually used to check a single perperties set to quickly know whether the perperties set is valid.

• IChain

  The interface of chain，build-in:

  • Predicate

    test()

  ​ Mainly for the verification of a single properties set, the verification rule of each property in the perperties set can be configured.

  • Function

    apply()

    Mainly for the verification of batch of properties set, the verification rule of the property between each perperties set can be configured.

    Build in the duplicate rule .

• ChainBuiler
  ​ Build the chain to use, build in.

---

How to use it

All the basic usage you can find indemo/App.java.

You can expand as much as you want, no matter the Rule, or the implementations of getting property value.

Requests JDK8+, the core is using the @FunctionalInterface.

Import

• Maven
  It has been published in Github Packages, you can import it directly, more details see the packages.

<dependency>
   <groupId>com.koy</groupId>
   <artifactId>kchain</artifactId>
   <version>${latest.version}</version>
</dependency>

Demo

---

Map

Suppose that we need to verify the name and age in map. The rules are as follows:

In Single Map

• name cannot empty
• agecan not empty
• age should in the cases

In Map Collections

• name cannot duplicate in collections

• age cannot duplicate in collections

Build the single properties set chain

• name cannot empty
• age cannot empty
• age should in [1,2,3,4,5]

    @Override
    public Predicate<MapDataWrapper> getPredicateChain(ChainContext ctx) {
        return Rule.NOT_EMPTY.<MapDataWrapper>testNotEmpty("name"
                , testEmptyRule("name")
                , resultProcessor("name", CheckResultCode.NOT_EMPTY))
                .and(Rule.NOT_EMPTY.testNotEmpty("age"
                        , testEmptyRule("age")
                        , resultProcessor("age", CheckResultCode.NOT_EMPTY)
                ))
                .and(Rule.IN_CASES.testInCases("age",
                        CommonTestComponents.testInCasesRule(dataWrapper -> Integer.valueOf(dataWrapper.getString("age"))
                                , Arrays.asList(1, 2, 3, 4, 5))
                        , resultProcessor("age", CheckResultCode.IN_CASES)
                ));

    }

Build the batch properties sets chain

• name cannot duplicated in batch of properties sets
• agecannot duplicated in batch of properties sets

    @Override
    public Function<List<MapDataWrapper>, List<MapDataWrapper>> getFunction(ChainContext ctx) {
        return CommonTestComponents.<MapDataWrapper>testDuplicatedInCollection(ctx
                , "name"
                , dataWrapper -> true, dataWrapper -> dataWrapper.getString("name"))
                .andThen(testDuplicatedInCollection(ctx
                        , "age"
                        , dataWrapper -> true
                        , dataWrapper -> dataWrapper.getString("age")));
    }

Usage

 public static void demoOnMapBuilder(List<HashMap<String, Object>> maps) {
        // Wrap data to DataWrapper
        List<MapDataWrapper> mapDataWrappers = Lists.newArrayListWithCapacity(2);
        for (HashMap<String, Object> map : maps) {
            MapDataWrapper mapDataWrapper = new MapDataWrapper(map, new MapRuleContext(RuleStrategy.FULL_CHECK));
            mapDataWrappers.add(mapDataWrapper);
        }

        // Build the chain with FULL_CHECK strategy
        Chain<MapDataWrapper, List<MapDataWrapper>> chain = ChainBuilder.newBuilder()
                .setChainContext(new ChainContext(RuleStrategy.FULL_CHECK))
                .setChain(new MapPropertiesCheckChain())
                .build();

        // Verify the property in the map
        // There use 6 threads execute it to make it speeder
        chain.test(mapDataWrappers);

        // Verify the rules between batch properties sets
        chain.apply(mapDataWrappers);

        // Show the result
        for (MapDataWrapper mapDataWrapper : mapDataWrappers) {
            System.out.println(mapDataWrapper.getRuleContext().getResult().toString());
        }

    }