discrod-ws: Improve BackoffRetryer

Move static fields into usage since they wher only used once.
Add logging on retry reset.

discord-ws/src/main/java/de/hhhammer/dchat/discord/ws/connection/BackoffRetryer.java

@@ -1,6 +1,8 @@
 package de.hhhammer.dchat.discord.ws.connection;
 
 import de.hhhammer.dchat.discord.ws.Retryer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.time.Duration;
 import java.time.LocalTime;
@@ -8,8 +10,7 @@ import java.util.Timer;
 import java.util.concurrent.atomic.AtomicInteger;
 
 public final class BackoffRetryer implements Retryer {
-    private static final int delayInSeconds = 10;
-    private static final int backoffMultiplier = 2;
+    private static final Logger logger = LoggerFactory.getLogger(BackoffRetryer.class);
     private final AtomicInteger tries = new AtomicInteger();
     private final int maxRetries;
     private LocalTime lastRetry = null;
@@ -24,8 +25,14 @@ public final class BackoffRetryer implements Retryer {
 
     public int nextRetryInSeconds() {
         // reset retry on successful connection for more than 5 minutes.
-        if (lastRetry != null && LocalTime.now().minusMinutes(lastRetry.getMinute()).getMinute() > 5) tries.set(0);
+        final int successfulTimeInMinute = 5;
+        if (lastRetry != null && LocalTime.now().minusMinutes(lastRetry.getMinute()).getMinute() > successfulTimeInMinute) {
+            logger.info("Resetting retry backoff: connection was successful for more than {} minutes", successfulTimeInMinute);
+            tries.set(0);
+        }
         final int currentTry = tries.getAndIncrement();
+        final int delayInSeconds = 10;
+        final int backoffMultiplier = 2;
         int seconds = delayInSeconds;
         for (int i = 0; i < currentTry; i++) {
             seconds = seconds * backoffMultiplier;

discord-ws/src/main/java/de/hhhammer/dchat/discord/ws/connection/ResumeConnector.java

@@ -5,7 +5,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 public final class ResumeConnector {
-    private static Logger logger = LoggerFactory.getLogger(ResumeConnector.class);
+    private static final Logger logger = LoggerFactory.getLogger(ResumeConnector.class);
     private final String initGatewayUrl;
     private final String token;