[Failsafe] Simple, sophisticated failure handling

Scenario
We have a Java application to connect to OPC server, if it fail to connect to OPC server it will retry 5 times.


How-to
You can make good use of Failsafe to fulfill this requirement. 
Failsafe is a lightweight, zero-dependency library for handling failures. It was designed to be as easy to use as possible, with a concise API for handling everyday use cases and the flexibility to handle everything else.

Maven dependency:

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<dependencies> <dependency> <groupId>net.jodah</groupId> <artifactId>failsafe</artifactId> <version>0.9.5</version> </dependency> </dependencies>

If I catch ConnectionException, it will do retry, the retry policy is as bellows:

• it will delay 2 seconds between retries
• it will retry 5 times at most

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package albert.practice.retry; import java.util.Calendar; import java.util.Date; import java.util.concurrent.TimeUnit; import lombok.extern.slf4j.Slf4j; import net.jodah.failsafe.Failsafe; import net.jodah.failsafe.RetryPolicy; @Slf4j public class RetryTest { public static void main(String[] args) throws ConnectionException { @SuppressWarnings("unchecked") RetryPolicy retryPolicy = new RetryPolicy().retryOn(ConnectionException.class) .withDelay(2, TimeUnit.SECONDS).withMaxRetries(5); Failsafe.with(retryPolicy).run(() -> new RetryTest().connect()); } public void connect() throws ConnectionException { log.debug("time=" + new Date(Calendar.getInstance().getTimeInMillis())); if (true) { throw new ConnectionException("connection fail!"); } } }

Reference
[1] https://github.com/jhalterman/failsafe