ld-demo-java

Java Sandbox for LaunchDarkly

FeatureProvider

The FeatureProvider class implements the LaunchDarkly client as a singleton. It uses the approach documented here: https://dzone.com/articles/java-singletons-using-enum

There is some fancy stuff in here for logging and checking that the environment variable for the LD_SDK_KEY exists. The most basic implementation of this could look like this:

package org.levlaz;

import com.launchdarkly.client.LDClient;

/**
 * Singleton Enum
 */
public enum FeatureProvider {
    INSTANCE;

    private LDClient ldClient = new LDClient(System.getenv("LD_SDK_KEY"));
    
    public LDClient getInstance() {
        checkEnv();
        return ldClient;
    }
}

Usage

You can run this without LauncDarkly, but feature flags will fall back to the hard coded fallback value. If you want to use LaunchDarkly you need the following:

1. A valid LD_SDK_KEY exported as an environment variable.
2. A feature flag called show-message that exists in the same environment that your LD_SDK_KEY maps to.

We use a Makefile to make it easier to build and run this project.

Building

You can run make build to build this project for the first time.

Running

You can run make run to run the project.