Issue resilience4j#1043: Allow the configuration of a IntervalBiFunct…

…ion in Spring Boot2 (resilience4j#1235)

resilience4j-core/src/main/java/io/github/resilience4j/core/ClassUtils.java

@@ -31,6 +31,20 @@ private ClassUtils() {
         // utils
     }
 
+    public static <T> IntervalBiFunction<T> instantiateIntervalBiFunctionClass(
+        Class<? extends IntervalBiFunction<T>> clazz) {
+        try {
+            Constructor<? extends IntervalBiFunction<T>> c = clazz.getConstructor();
+            if (c != null) {
+                return c.newInstance();
+            } else {
+                throw new InstantiationException(INSTANTIATION_ERROR_PREFIX + clazz.getName());
+            }
+        } catch (Exception e) {
+            throw new InstantiationException(INSTANTIATION_ERROR_PREFIX + clazz.getName(), e);
+        }
+    }
+
     public static <T> Predicate<T> instantiatePredicateClass(Class<? extends Predicate<T>> clazz) {
         try {
             Constructor<? extends Predicate<T>> c = clazz.getConstructor();

resilience4j-framework-common/src/main/java/io/github/resilience4j/common/retry/configuration/RetryConfigurationProperties.java

@@ -21,6 +21,7 @@
 import io.github.resilience4j.core.ClassUtils;
 import io.github.resilience4j.core.ConfigurationNotFoundException;
 import io.github.resilience4j.core.IntervalFunction;
+import io.github.resilience4j.core.IntervalBiFunction;
 import io.github.resilience4j.core.StringUtils;
 import io.github.resilience4j.core.lang.Nullable;
 import io.github.resilience4j.retry.RetryConfig;
@@ -150,6 +151,11 @@ private RetryConfig buildRetryConfig(RetryConfig.Builder builder,
                 .instantiatePredicateClass(properties.getResultPredicate());
             builder.retryOnResult(predicate);
         }
+        if (properties.getIntervalBiFunction() != null) {
+            IntervalBiFunction<Object> intervalBiFunction = ClassUtils
+                .instantiateIntervalBiFunctionClass(properties.getIntervalBiFunction());
+            builder.intervalBiFunction(intervalBiFunction);
+        }
 
         compositeRetryCustomizer.getCustomizer(backend)
             .ifPresent(customizer -> customizer.customize(builder));
@@ -243,6 +249,12 @@ public static class InstanceProperties {
         @Nullable
         private Duration waitDuration;
 
+        /*
+         * retry intervalBiFunction class to be used to calculate wait based on exception or result
+         */
+        @Nullable
+        private Class<? extends IntervalBiFunction<Object>> intervalBiFunction;
+
         /*
          * max retry attempts value
          */
@@ -331,6 +343,15 @@ public InstanceProperties setWaitDuration(Duration waitDuration) {
             return this;
         }
 
+        @Nullable
+        public Class<? extends IntervalBiFunction<Object>> getIntervalBiFunction() {
+            return intervalBiFunction;
+        }
+
+        public void setIntervalBiFunction(Class<? extends IntervalBiFunction<Object>> intervalBiFunction) {
+            this.intervalBiFunction = intervalBiFunction;
+        }
+
         @Nullable
         @Deprecated
         public Integer getMaxRetryAttempts() {

resilience4j-framework-common/src/test/java/io/github/resilience4j/common/TestIntervalBiFunction.java

@@ -0,0 +1,11 @@
+package io.github.resilience4j.common;
+
+import io.github.resilience4j.core.IntervalBiFunction;
+import io.vavr.control.Either;
+
+public class TestIntervalBiFunction implements IntervalBiFunction<Object> {
+    @Override
+    public Long apply(Integer integer, Either<Throwable, Object> objects) {
+        return 200L;
+    }
+}

resilience4j-framework-common/src/test/java/io/github/resilience4j/common/retry/configuration/RetryConfigurationPropertiesTest.java

@@ -17,6 +17,7 @@
 
 import io.github.resilience4j.common.CompositeCustomizer;
 import io.github.resilience4j.common.RecordFailurePredicate;
+import io.github.resilience4j.common.TestIntervalBiFunction;
 import io.github.resilience4j.core.ConfigurationNotFoundException;
 import io.github.resilience4j.retry.RetryConfig;
 import org.junit.Test;
@@ -190,4 +191,19 @@ public void testIllegalArgumentOnMaxAttempts() {
     private CompositeCustomizer<RetryConfigCustomizer> compositeRetryCustomizer() {
         return new CompositeCustomizer<>(Collections.emptyList());
     }
+
+    @Test
+    public void testIntervalBiFunctionConfig() {
+        RetryConfigurationProperties.InstanceProperties instanceProperties = new RetryConfigurationProperties.InstanceProperties();
+        instanceProperties.setIntervalBiFunction(TestIntervalBiFunction.class);
+
+        RetryConfigurationProperties retryConfigurationProperties = new RetryConfigurationProperties();
+        retryConfigurationProperties.getInstances().put("backend", instanceProperties);
+
+        RetryConfig retryConfig = retryConfigurationProperties
+            .createRetryConfig("backend", compositeRetryCustomizer());
+
+        assertThat(retryConfig.getIntervalBiFunction()).isNotNull();
+        assertThat(retryConfig.getIntervalBiFunction()).isExactlyInstanceOf(TestIntervalBiFunction.class);
+    }
 }