com.gemstone.gemfire.cache.hdfs.internal.FailureTracker.java Source code

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Here is the source code for com.gemstone.gemfire.cache.hdfs.internal.FailureTracker.java

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/*
 * 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 com.gemstone.gemfire.cache.hdfs.internal;

import org.apache.commons.lang.mutable.MutableInt;
import org.apache.commons.lang.mutable.MutableLong;

/**
 * Class for tracking failures and backing off if necessary.
 * @author dsmith
 *
 */
public class FailureTracker extends ThreadLocal<MutableInt> {
    private final long minTime;
    private final long maxTime;
    private final float rate;
    private final FailureCount waitTime = new FailureCount();

    /**
     * @param minTime the minimum wait time after a failure in ms.
     * @param maxTime the maximum wait tim after a failure, in ms.
     * @param rate the rate of growth of the failures
     */
    public FailureTracker(long minTime, long maxTime, float rate) {
        this.minTime = minTime;
        this.maxTime = maxTime;
        this.rate = rate;
    }

    /**
     * Wait for the current wait time.
     */
    public void sleepIfRetry() throws InterruptedException {
        Thread.sleep(waitTime());
    }

    /**
     * @return the wait time = rate^(num_failures) * minTime
     */
    public long waitTime() {
        return waitTime.get().longValue();
    }

    public void record(boolean success) {
        if (success) {
            success();
        } else {
            failure();
        }

    }

    public void success() {
        waitTime.get().setValue(0);

    }

    public void failure() {
        long current = waitTime.get().intValue();
        if (current == 0) {
            current = minTime;
        } else if (current < maxTime) {
            current = (long) (current * rate);
        }
        waitTime.get().setValue(Math.min(current, maxTime));
    }

    private static class FailureCount extends ThreadLocal<MutableLong> {

        @Override
        protected MutableLong initialValue() {
            return new MutableLong();
        }
    }

}