com.metamx.common.RetryUtils.java Source code

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Here is the source code for com.metamx.common.RetryUtils.java

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/*
 * Copyright 2011 - 2015 Metamarkets Group Inc.
 *
 * 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
 *
 *     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 com.metamx.common;

import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.base.Throwables;
import com.metamx.common.logger.Logger;

import java.util.Random;
import java.util.concurrent.Callable;

public class RetryUtils {
    public static final Logger log = new Logger(RetryUtils.class);

    public static <T> T retry(final Callable<T> f, Predicate<Throwable> shouldRetry, final int maxTries)
            throws Exception {
        Preconditions.checkArgument(maxTries > 0, "maxTries > 0");
        int nTry = 0;
        while (true) {
            try {
                nTry++;
                return f.call();
            } catch (Throwable e) {
                if (nTry < maxTries && shouldRetry.apply(e)) {
                    awaitNextRetry(e, nTry);
                } else {
                    Throwables.propagateIfInstanceOf(e, Exception.class);
                    throw Throwables.propagate(e);
                }
            }
        }
    }

    private static void awaitNextRetry(final Throwable e, final int nTry) throws InterruptedException {
        final long baseSleepMillis = 1000;
        final long maxSleepMillis = 60000;
        final double fuzzyMultiplier = Math.min(Math.max(1 + 0.2 * new Random().nextGaussian(), 0), 2);
        final long sleepMillis = (long) (Math.min(maxSleepMillis, baseSleepMillis * Math.pow(2, nTry))
                * fuzzyMultiplier);
        log.warn(e, "Failed on try %d, retrying in %,dms.", nTry, sleepMillis);
        Thread.sleep(sleepMillis);
    }
}