Create a dynamic config engine in 5 minutes, using Java

Create a dynamic config engine in 5 minutes, using Java What is a runtime hierarchical config engine?

A hierarchical config engine is a collection of config rules, where the rules get more specific as you travel down your hierarchy. The rules apply to each request in runtime, so its a runtime hierarchical config engine

For example you can have below config rules :-

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Config rules

These config rules would mean:-

• All Airlines in US have a surcharge of 1.00, with following exceptions:-
  • Delta (dl) airlines in US has a surcharge of 3.00
  • All airlines in us and nyc has a surcharge of 2.50 with following exceptions:-
    • Delta airlines in us and nyc has a surcharge of 5.50
    • American airlines (aa) in us and nyc has a surcharge of 4.50
• All Delta flights across the world have a surcharge of 6.00

So the idea is that you can define general rules and more specific rules and the most specific rule will apply to your runtime record.

What are we building in this example

Let’s build a simple runtime config engine that applies a surcharge to customer selected flight based on origin’s country, city and airline.

Step 1: Get Kiara

<dependency>
	<groupId>com.kapoorlabs</groupId>
	<artifactId>kiara</artifactId>
	<version>2.0.10</version>
</dependency>

Step 2: Create your Config Data POJO

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Config {

	private String country;
	
	private String originCity;
	
	private String airline;
	
	private Double surcharge;
	
}

Create your config store

import com.kapoorlabs.kiara.domain.Store;
import com.kapoorlabs.kiara.exception.LoadDataException;
import com.kapoorlabs.kiara.loader.StoreLoader;

	public void loadConfigStore() throws LoadDataException {
		configStore = new Store<>(Config.class);
		StoreLoader<Config> storeLoader = new StoreLoader<>(configStore);

		storeLoader.loadTable(new Config("in", null, null, 2.00));
		storeLoader.loadTable(new Config("us", null, null, 1.00));
		storeLoader.loadTable(new Config("us", null, "dl", 3.00));
		storeLoader.loadTable(new Config("us", "nyc", null, 2.50));
		storeLoader.loadTable(new Config("us", "nyc", "aa", 4.50));
		storeLoader.loadTable(new Config("us", "nyc", "dl", 5.50));

		storeLoader.prepareForSearch();

	}

In this example we are just loading the config data from within the source code, but the source of the config data can be any data store, such as a file, database, a network stream, etc.

Write your search method that applies config rule

import com.kapoorlabs.kiara.domain.Store;
import com.kapoorlabs.kiara.exception.LoadDataException;
import com.kapoorlabs.kiara.loader.StoreLoader;

	public Double getSurcharge(Store<Config> configStore, FlightRecord flightRecord) {
		String country = flightRecord.getCountry();
		
		String city = flightRecord.getCity();
		
		String airline = flightRecord.getAirline();

		KeywordSearchResult<Config> result = keywordSearch.getMinimumMatch(country + " " + city + " " + airline, configStore);

                Double surcharge = result.getResult().get(0).getSurCharge()

                return surcharge;

	}

And your are Done!

Explaining Results

Given you have following rules: –

Config rules

The following results should be self explanatory, but feel free to post a question in comments, in case of any doubt.

keywordSearch.getMinimumMatch(” us “, configStore); -> will give you surcharge of 1.00

keywordSearch.getMinimumMatch(” us dl”, configStore); -> will give you surcharge of 3.00

keywordSearch.getMinimumMatch(” nyc us dl”, configStore); -> will give you surcharge of 5.50

keywordSearch.getMinimumMatch(” bos us dl”, configStore); -> will give you surcharge of 3.00

keywordSearch.getMinimumMatch(” us nyc jb”, configStore); -> will give you surcharge of 2.50

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https://www.deviantart.com/gdsffds/journal/Create-a-dynamic-config-engine-in-5-minutes-usin-873925623

https://paiza.io/projects/jWCd_FuOMq0EovUlf9XnWA

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https://www.thewyco.com/general/create-a-dynamic-config-engine-in-5-minutes-using-java-21-03-2021