Creating RetryExecutor to inject it as a dependency in other components

google-cloud-datastore/src/main/java/com/google/cloud/datastore/RetryExecutor.java

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+/*
+ * Copyright 2022 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.cloud.datastore;
+
+import com.google.api.core.ApiClock;
+import com.google.api.gax.retrying.ResultRetryAlgorithm;
+import com.google.api.gax.retrying.RetrySettings;
+import com.google.cloud.RetryHelper;
+import java.util.concurrent.Callable;
+
+public class RetryExecutor {
+
+  public <T> T execute(Callable<T> block, RetrySettings retrySettings,
+      ResultRetryAlgorithm<?> resultRetryAlgorithm, ApiClock clock) {
+    return RetryHelper.runWithRetries(block, retrySettings, resultRetryAlgorithm, clock);
+  }
+
+}

google-cloud-datastore/src/test/java/com/google/cloud/datastore/RetryExecutorTest.java

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+/*
+ * Copyright 2022 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.cloud.datastore;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+import com.google.api.core.NanoClock;
+import com.google.api.gax.retrying.BasicResultRetryAlgorithm;
+import com.google.api.gax.retrying.RetrySettings;
+import java.util.concurrent.Callable;
+import org.junit.Test;
+
+public class RetryExecutorTest {
+
+  private RetryExecutor retryExecutor = new RetryExecutor();
+
+  @Test
+  public void shouldRetryWhenErrorOccurred() {
+    RetrySettings retrySettings = RetrySettings.newBuilder()
+        .setMaxAttempts(4)
+        .build();
+    CustomErrorCallable callable = new CustomErrorCallable(3);
+
+    retryExecutor.execute(callable, retrySettings, new BasicResultRetryAlgorithm<>(),
+        NanoClock.getDefaultClock());
+
+    assertThat(callable.invokedTimes(), equalTo(4));
+  }
+
+  private static class CustomErrorCallable implements Callable<String> {
+
+    private final int errorThreshold;
+    private int numberOfInvocations;
+
+    public CustomErrorCallable(int errorThreshold) {
+      this.errorThreshold = errorThreshold;
+      this.numberOfInvocations = 0;
+    }
+
+    @Override
+    public String call() throws Exception {
+      this.numberOfInvocations++;
+      if (this.numberOfInvocations <= errorThreshold) {
+        throw new RuntimeException("error");
+      }
+      return "success";
+    }
+
+    public int invokedTimes() {
+      return this.numberOfInvocations;
+    }
+  }
+}
+