issue #707 ExponentialBackOff refactored to interface for custom implementation

pom.xml

@@ -178,6 +178,23 @@
         </dependency>
     </dependencies>
 
+<!--    <reporting>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-checkstyle-plugin</artifactId>
+                <version>3.1.2</version>
+                <reportSets>
+                    <reportSet>
+                        <reports>
+                            <report>checkstyle</report>
+                        </reports>
+                    </reportSet>
+                </reportSets>
+            </plugin>
+        </plugins>
+    </reporting>-->
+
     <build>
         <plugins>
             <plugin>

telegrambots-meta/src/main/java/org/telegram/telegrambots/meta/generics/BackOff.java

@@ -0,0 +1,19 @@
+package org.telegram.telegrambots.meta.generics;
+
+/**
+ * @author Calvin
+ * @version 1.0
+ * Interface for backoff retries
+ */
+public interface BackOff {
+
+    /**
+     * Should be able to reset to the starting
+     */
+    void reset();
+
+    /**
+     * specify the next backoff interval in milliseconds
+     */
+    long nextBackOffMillis();
+}

telegrambots/src/main/java/org/telegram/telegrambots/bots/DefaultBotOptions.java

@@ -5,7 +5,7 @@ import org.apache.http.client.protocol.HttpClientContext;
 import org.apache.http.protocol.HttpContext;
 import org.telegram.telegrambots.meta.ApiConstants;
 import org.telegram.telegrambots.meta.generics.BotOptions;
-import org.telegram.telegrambots.updatesreceivers.ExponentialBackOff;
+import org.telegram.telegrambots.meta.generics.BackOff;
 
 import java.util.List;
 
@@ -19,7 +19,7 @@ public class DefaultBotOptions implements BotOptions {
     private int maxThreads; ///< Max number of threads used for async methods executions (default 1)
     private RequestConfig requestConfig;
     private volatile HttpContext httpContext;
-    private ExponentialBackOff exponentialBackOff;
+    private BackOff backOff;
     private Integer maxWebhookConnections;
     private String baseUrl;
     private List<String> allowedUpdates;
@@ -91,23 +91,23 @@ public class DefaultBotOptions implements BotOptions {
     }
 
     /**
-     * @implSpec Default implementation assumes no proxy is needed and sets a 75secs timoute
      * @param requestConfig Request config to be used in all Http requests
+     * @implSpec Default implementation assumes no proxy is needed and sets a 75secs timoute
      */
     public void setRequestConfig(RequestConfig requestConfig) {
         this.requestConfig = requestConfig;
     }
 
-    public ExponentialBackOff getExponentialBackOff() {
+    public BackOff getBackOff() {
-        return exponentialBackOff;
+        return backOff;
     }
 
     /**
+     * @param BackOff backOff to be used when long polling fails
      * @implSpec Default implementation assumes starting at 500ms and max time of 60 minutes
-     * @param exponentialBackOff ExponentialBackOff to be used when long polling fails
      */
-    public void setExponentialBackOff(ExponentialBackOff exponentialBackOff) {
+    public void setBackOff(BackOff BackOff) {
-        this.exponentialBackOff = exponentialBackOff;
+        this.backOff = BackOff;
     }
 
     public ProxyType getProxyType() {

telegrambots/src/main/java/org/telegram/telegrambots/updatesreceivers/DefaultBotSession.java

@@ -16,11 +16,7 @@ import org.telegram.telegrambots.facilities.TelegramHttpClientBuilder;
 import org.telegram.telegrambots.meta.api.methods.updates.GetUpdates;
 import org.telegram.telegrambots.meta.api.objects.Update;
 import org.telegram.telegrambots.meta.exceptions.TelegramApiRequestException;
-import org.telegram.telegrambots.meta.generics.BotOptions;
+import org.telegram.telegrambots.meta.generics.*;
-import org.telegram.telegrambots.meta.generics.BotSession;
-import org.telegram.telegrambots.meta.generics.LongPollingBot;
-import org.telegram.telegrambots.meta.generics.UpdatesHandler;
-import org.telegram.telegrambots.meta.generics.UpdatesReader;
 
 import java.io.IOException;
 import java.io.InvalidObjectException;
@@ -142,7 +138,7 @@ public class DefaultBotSession implements BotSession {
         private final UpdatesSupplier updatesSupplier;
         private final Object lock;
         private CloseableHttpClient httpclient;
-        private ExponentialBackOff exponentialBackOff;
+        private BackOff backOff;
         private RequestConfig requestConfig;
 
         public ReaderThread(UpdatesSupplier updatesSupplier, Object lock) {
@@ -154,10 +150,11 @@ public class DefaultBotSession implements BotSession {
         public synchronized void start() {
             httpclient = TelegramHttpClientBuilder.build(options);
             requestConfig = options.getRequestConfig();
-            exponentialBackOff = options.getExponentialBackOff();
+            backOff = options.getBackOff();
 
-            if (exponentialBackOff == null) {
+            // fall back to default exponential backoff strategy if no backoff specified
-                exponentialBackOff = new ExponentialBackOff();
+            if (backOff == null) {
+                backOff = new ExponentialBackOff();
             }
 
             if (requestConfig == null) {
@@ -215,7 +212,7 @@ public class DefaultBotSession implements BotSession {
                             log.error(global.getLocalizedMessage(), global);
                             try {
                                 synchronized (lock) {
-                                    lock.wait(exponentialBackOff.nextBackOffMillis());
+                                    lock.wait(backOff.nextBackOffMillis());
                                 }
                             } catch (InterruptedException e) {
                                 if (!running.get()) {
@@ -261,7 +258,7 @@ public class DefaultBotSession implements BotSession {
                 } else {
                     try {
                         List<Update> updates = request.deserializeResponse(responseContent);
-                        exponentialBackOff.reset();
+                        backOff.reset();
                         return updates;
                     } catch (JSONException e) {
                         log.error("Error deserializing update: " + responseContent, e);

telegrambots/src/main/java/org/telegram/telegrambots/updatesreceivers/ExponentialBackOff.java

@@ -14,6 +14,7 @@
 package org.telegram.telegrambots.updatesreceivers;
 
 import com.google.common.base.Preconditions;
+import org.telegram.telegrambots.meta.generics.BackOff;
 
 /**
  * Implementation of BackOff that increases the back off period for each retry attempt using
@@ -68,7 +69,7 @@ import com.google.common.base.Preconditions;
  * @since 1.15
  * @author Ravi Mistry
  */
-public class ExponentialBackOff {
+public class ExponentialBackOff implements BackOff {
     /** The default initial interval value in milliseconds (0.5 seconds). */
     private static final int DEFAULT_INITIAL_INTERVAL_MILLIS = 500;
 
@@ -82,7 +83,7 @@ public class ExponentialBackOff {
     private static final double DEFAULT_MULTIPLIER = 1.5;
 
     /** The default maximum back off time in milliseconds (15 minutes). */
-    private static final int DEFAULT_MAX_INTERVAL_MILLIS = 30000;
+    private static final int DEFAULT_MAX_INTERVAL_MILLIS = 900000;
 
     /** The default maximum elapsed time in milliseconds (60 minutes). */
     private static final int DEFAULT_MAX_ELAPSED_TIME_MILLIS = 3600000;
@@ -161,7 +162,8 @@ public class ExponentialBackOff {
     }
 
     /** Sets the interval back to the initial retry interval and restarts the timer. */
-    final void reset() {
+    @Override
+    public void reset() {
         currentIntervalMillis = initialIntervalMillis;
         startTimeNanos = nanoTime();
     }
@@ -178,7 +180,8 @@ public class ExponentialBackOff {
      * Subclasses may override if a different algorithm is required.
      * </p>
      */
-    long nextBackOffMillis() {
+    @Override
+    public long nextBackOffMillis() {
         // Make sure we have not gone over the maximum elapsed time.
         if (getElapsedTimeMillis() > maxElapsedTimeMillis) {
             return maxElapsedTimeMillis;
@@ -274,7 +277,32 @@ public class ExponentialBackOff {
          */
         int maxElapsedTimeMillis = DEFAULT_MAX_ELAPSED_TIME_MILLIS;
 
-        Builder() {
+        public Builder() {
+        }
+
+        public Builder setInitialIntervalMillis(int initialIntervalMillis) {
+            this.initialIntervalMillis = initialIntervalMillis;
+            return this;
+        }
+
+        public Builder setRandomizationFactor(double randomizationFactor) {
+            this.randomizationFactor = randomizationFactor;
+            return this;
+        }
+
+        public Builder setMultiplier(double multiplier) {
+            this.multiplier = multiplier;
+            return this;
+        }
+
+        public Builder setMaxIntervalMillis(int maxIntervalMillis) {
+            this.maxIntervalMillis = maxIntervalMillis;
+            return this;
+        }
+
+        public Builder setMaxElapsedTimeMillis(int maxElapsedTimeMillis) {
+            this.maxElapsedTimeMillis = maxElapsedTimeMillis;
+            return this;
         }
 
         /** Builds a new instance of {@link ExponentialBackOff}. */

telegrambots/src/test/java/org/telegram/telegrambots/test/TestDefaultBotSession.java

@@ -15,9 +15,11 @@ import org.mockito.Mockito;
 import org.telegram.telegrambots.bots.DefaultBotOptions;
 import org.telegram.telegrambots.meta.TelegramBotsApi;
 import org.telegram.telegrambots.meta.api.objects.Update;
+import org.telegram.telegrambots.meta.generics.BackOff;
 import org.telegram.telegrambots.meta.generics.LongPollingBot;
 import org.telegram.telegrambots.test.Fakes.FakeLongPollingBot;
 import org.telegram.telegrambots.updatesreceivers.DefaultBotSession;
+import org.telegram.telegrambots.updatesreceivers.ExponentialBackOff;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -139,6 +141,30 @@ public class TestDefaultBotSession {
         session.stop();
     }
 
+    @Test
+    public void testDefaultBotSessionWithCustomExponentialBackOff() {
+        ExponentialBackOff ex = new ExponentialBackOff.Builder()
+                .setInitialIntervalMillis(500)
+                .setRandomizationFactor(0.5)
+                .setMultiplier(1.5)
+                .setMaxIntervalMillis(900000)
+                .setMaxElapsedTimeMillis(3600000)
+                .build();
+        DefaultBotOptions options = new DefaultBotOptions();
+        options.setBackOff(ex);
+        DefaultBotSession session = new DefaultBotSession();
+        session.setOptions(options);
+    }
+
+    @Test
+    public void testDefaultBotSessionWithCustomConstantBackOff() {
+        DefaultBotOptions options = new DefaultBotOptions();
+        ConstantBackOff backOff = new ConstantBackOff(3000);
+        options.setBackOff(backOff);
+        DefaultBotSession session = new DefaultBotSession();
+        session.setOptions(options);
+    }
+
     private Update[] createFakeUpdates(int count) {
         return IntStream.range(0, count).mapToObj(x -> {
             Update mock = Mockito.mock(Update.class);
@@ -178,4 +204,26 @@ public class TestDefaultBotSession {
         session.setOptions(new DefaultBotOptions());
         return session;
     }
+
+    private static class ConstantBackOff implements BackOff {
+
+        private long backOffMillis;
+
+        ConstantBackOff() {
+            new ConstantBackOff(3000);
+        }
+
+        ConstantBackOff(long millis) {
+            this.backOffMillis = millis;
+        }
+
+        @Override
+        public void reset() {
+        }
+
+        @Override
+        public long nextBackOffMillis() {
+            return backOffMillis;
+        }
+    }
 }