[GitHub] [geode] pivotal-jbarrett commented on a change in pull request #5743: GEODE-8623: Retry getting local host if it fails.

[GitBox <gi...@apache.org>]

pivotal-jbarrett commented on a change in pull request #5743:
URL: https://github.com/apache/geode/pull/5743#discussion_r522525345



##########
File path: geode-common/src/main/java/org/apache/geode/internal/Retry.java
##########
@@ -0,0 +1,92 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more contributor license
+ * agreements. See the NOTICE file distributed with this work for additional information regarding
+ * copyright ownership. The ASF licenses this file to You 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
+ *
+ * http://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 org.apache.geode.internal;
+
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static java.util.concurrent.TimeUnit.NANOSECONDS;
+
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import java.util.function.Predicate;
+import java.util.function.Supplier;
+
+import org.apache.geode.annotations.VisibleForTesting;
+
+/**
+ * Utility class for retrying operations.
+ */
+public class Retry {
+
+  interface Clock {
+    long nanoTime();
+
+    void sleep(long sleepTime, TimeUnit sleepTimeUnit) throws InterruptedException;
+  }
+
+  private static class SteadyClock implements Clock {
+    @Override
+    public long nanoTime() {
+      return System.nanoTime();
+    }
+
+    @Override
+    public void sleep(long sleepTime, TimeUnit sleepTimeUnit) throws InterruptedException {

Review comment:
       Sleeping doesn't feel like the responsibility of a clock.

##########
File path: geode-common/src/main/java/org/apache/geode/internal/Retry.java
##########
@@ -0,0 +1,92 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more contributor license
+ * agreements. See the NOTICE file distributed with this work for additional information regarding
+ * copyright ownership. The ASF licenses this file to You 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
+ *
+ * http://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 org.apache.geode.internal;
+
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static java.util.concurrent.TimeUnit.NANOSECONDS;
+
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import java.util.function.Predicate;
+import java.util.function.Supplier;
+
+import org.apache.geode.annotations.VisibleForTesting;
+
+/**
+ * Utility class for retrying operations.
+ */
+public class Retry {
+
+  interface Clock {
+    long nanoTime();
+
+    void sleep(long sleepTime, TimeUnit sleepTimeUnit) throws InterruptedException;
+  }
+
+  private static class SteadyClock implements Clock {
+    @Override
+    public long nanoTime() {
+      return System.nanoTime();
+    }
+
+    @Override
+    public void sleep(long sleepTime, TimeUnit sleepTimeUnit) throws InterruptedException {
+      Thread.sleep(MILLISECONDS.convert(sleepTime, sleepTimeUnit));
+    }
+  }
+
+  private static final SteadyClock steadyClock = new SteadyClock();
+
+  /**
+   * Try the supplier function until the predicate is true or timeout occurs.
+   *
+   * @param timeout to retry for
+   * @param interval time between each try
+   * @param timeUnit to retry for
+   * @param supplier to execute until predicate is true or times out
+   * @param predicate to test for retry
+   * @param <T> type of return value
+   * @return value from supplier after it passes predicate or times out.
+   */
+  public static <T> T tryFor(long timeout,
+      long interval,
+      TimeUnit timeUnit,
+      Supplier<T> supplier,
+      Predicate<T> predicate) throws TimeoutException, InterruptedException {
+    return tryFor(timeout, interval, timeUnit, supplier, predicate, steadyClock);
+  }
+
+  @VisibleForTesting
+  static <T> T tryFor(long timeout,
+      long interval,
+      TimeUnit timeUnit,

Review comment:
       Is TimeUnit intended to cover both time values? I think its more readable to have TimeUnit param for each so it reads as "(1, SECOND, 4,  SECOND)" rather than "(1, 4, SECOND)".




----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
users@infra.apache.org