优化

common-core/src/main/java/com/baiyue/common/core/retry/BoundedRetryPolicy.java

@@ -0,0 +1,31 @@
+package com.baiyue.common.core.retry;
+
+import java.time.Duration;
+import java.util.concurrent.ThreadLocalRandom;
+
+/** Bounded exponential retry schedule; callers persist failed or expired attempts. */
+public record BoundedRetryPolicy(int maxAttempts, long baseDelaySeconds, long maxDelaySeconds, double jitter) {
+    public BoundedRetryPolicy {
+        if (maxAttempts < 1 || baseDelaySeconds < 1 || maxDelaySeconds < baseDelaySeconds
+                || maxDelaySeconds > 86400 || !Double.isFinite(jitter) || jitter < 0 || jitter > 0.5) {
+            throw new IllegalArgumentException("Invalid bounded retry policy");
+        }
+    }
+    public boolean exhausted(int failedAttempts) {
+        return failedAttempts >= maxAttempts;
+    }
+    public Duration delayAfterFailure(int failedAttempts) {
+        return delayAfterFailure(failedAttempts, ThreadLocalRandom.current().nextDouble());
+    }
+    public Duration delayAfterFailure(int failedAttempts, double random) {
+        if (failedAttempts < 1 || !Double.isFinite(random) || random < 0 || random > 1) {
+            throw new IllegalArgumentException("Invalid retry attempt or jitter sample");
+        }
+        long seconds = baseDelaySeconds;
+        for (int i = 1; i < failedAttempts && seconds < maxDelaySeconds; i++) {
+            seconds = Math.min(maxDelaySeconds, seconds * 2);
+        }
+        long millis = Math.round(seconds * 1000 * (1 - jitter + 2 * jitter * random));
+        return Duration.ofMillis(Math.min(maxDelaySeconds * 1000, Math.max(1, millis)));
+    }
+}

common-core/src/test/java/com/baiyue/common/core/BoundedRetryPolicyTest.java

@@ -0,0 +1,31 @@
+package com.baiyue.common.core;
+
+import com.baiyue.common.core.retry.BoundedRetryPolicy;
+import org.junit.jupiter.api.Test;
+import static org.assertj.core.api.Assertions.*;
+
+class BoundedRetryPolicyTest {
+    @Test void startsAtFiveSecondsDoublesAndCapsAtThirtyMinutes() {
+        var policy = new BoundedRetryPolicy(12, 5, 1800, 0);
+        assertThat(policy.delayAfterFailure(1).toSeconds()).isEqualTo(5);
+        assertThat(policy.delayAfterFailure(2).toSeconds()).isEqualTo(10);
+        assertThat(policy.delayAfterFailure(9).toSeconds()).isEqualTo(1280);
+        assertThat(policy.delayAfterFailure(10).toSeconds()).isEqualTo(1800);
+        assertThat(policy.delayAfterFailure(Integer.MAX_VALUE).toSeconds()).isEqualTo(1800);
+        assertThat(policy.exhausted(11)).isFalse();
+        assertThat(policy.exhausted(12)).isTrue();
+    }
+    @Test void jitterStaysBoundedEvenAtMaximumDelay() {
+        var policy = new BoundedRetryPolicy(12, 5, 1800, 0.1);
+        assertThat(policy.delayAfterFailure(1, 0).toMillis()).isEqualTo(4500);
+        assertThat(policy.delayAfterFailure(1, 1).toMillis()).isEqualTo(5500);
+        assertThat(policy.delayAfterFailure(20, 1).toSeconds()).isEqualTo(1800);
+        assertThat(policy.delayAfterFailure(20, 0).toSeconds()).isEqualTo(1620);
+    }
+    @Test void invalidConfigurationFailsClosed() {
+        assertThatThrownBy(() -> new BoundedRetryPolicy(0, 5, 1800, 0.1)).isInstanceOf(IllegalArgumentException.class);
+        assertThatThrownBy(() -> new BoundedRetryPolicy(12, 0, 1800, 0.1)).isInstanceOf(IllegalArgumentException.class);
+        assertThatThrownBy(() -> new BoundedRetryPolicy(12, 5, 3, 0.1)).isInstanceOf(IllegalArgumentException.class);
+        assertThatThrownBy(() -> new BoundedRetryPolicy(12, 5, 1800, Double.NaN)).isInstanceOf(IllegalArgumentException.class);
+    }
+}