org.apache.hadoop.hbase.client.SpeculativeRequester.java Source code

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Here is the source code for org.apache.hadoop.hbase.client.SpeculativeRequester.java

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/**
 * Licensed to Cloudera, Inc. under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  Cloudera, Inc. 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.hadoop.hbase.client;

import java.util.ArrayList;
import java.util.Collection;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorCompletionService;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class SpeculativeRequester<T extends Object> {

    long waitTimeBeforeRequestingFailover;
    long waitTimeBeforeAcceptingResults;
    AtomicLong lastPrimaryFail;
    long waitTimeFromLastPrimaryFail;

    static final Log LOG = LogFactory.getLog(SpeculativeRequester.class);

    ExecutorService exe = Executors.newFixedThreadPool(200);

    public SpeculativeRequester(long waitTimeBeforeRequestingFailover, long waitTimeBeforeAcceptingResults,
            AtomicLong lastPrimaryFail, long waitTimeFromLastPrimaryFail) {
        this.waitTimeBeforeRequestingFailover = waitTimeBeforeRequestingFailover;
        this.waitTimeBeforeAcceptingResults = waitTimeBeforeAcceptingResults;
        this.lastPrimaryFail = lastPrimaryFail;
        this.waitTimeFromLastPrimaryFail = waitTimeFromLastPrimaryFail;
    }

    public ResultWrapper<T> request(final HBaseTableFunction<T> function, final HTableInterface primaryTable,
            final Collection<HTableInterface> failoverTables) {

        ExecutorCompletionService<ResultWrapper<T>> exeS = new ExecutorCompletionService<ResultWrapper<T>>(exe);

        final AtomicBoolean isPrimarySuccess = new AtomicBoolean(false);
        final long startTime = System.currentTimeMillis();

        ArrayList<Callable<ResultWrapper<T>>> callables = new ArrayList<Callable<ResultWrapper<T>>>();

        if (System.currentTimeMillis() - lastPrimaryFail.get() > waitTimeFromLastPrimaryFail) {
            callables.add(new Callable<ResultWrapper<T>>() {
                public ResultWrapper<T> call() throws Exception {
                    try {
                        T t = function.call(primaryTable);
                        isPrimarySuccess.set(true);
                        return new ResultWrapper(true, t);
                    } catch (java.io.InterruptedIOException e) {
                        Thread.currentThread().interrupt();
                    } catch (Exception e) {
                        lastPrimaryFail.set(System.currentTimeMillis());
                        Thread.currentThread().interrupt();
                    }
                    return null;
                }
            });
        }

        for (final HTableInterface failoverTable : failoverTables) {
            callables.add(new Callable<ResultWrapper<T>>() {

                public ResultWrapper<T> call() throws Exception {

                    long waitToRequest = (System.currentTimeMillis()
                            - lastPrimaryFail.get() > waitTimeFromLastPrimaryFail)
                                    ? waitTimeBeforeRequestingFailover - (System.currentTimeMillis() - startTime)
                                    : 0;

                    if (waitToRequest > 0) {
                        Thread.sleep(waitToRequest);
                    }
                    if (isPrimarySuccess.get() == false) {
                        T t = function.call(failoverTable);

                        long waitToAccept = (System.currentTimeMillis()
                                - lastPrimaryFail.get() > waitTimeFromLastPrimaryFail)
                                        ? waitTimeBeforeAcceptingResults - (System.currentTimeMillis() - startTime)
                                        : 0;
                        if (isPrimarySuccess.get() == false) {
                            if (waitToAccept > 0) {
                                Thread.sleep(waitToAccept);
                            }
                        }

                        return new ResultWrapper(false, t);
                    } else {
                        throw new RuntimeException("Not needed");
                    }

                }
            });
        }
        try {

            //ResultWrapper<T> t = exe.invokeAny(callables);
            for (Callable<ResultWrapper<T>> call : callables) {
                exeS.submit(call);
            }

            ResultWrapper<T> result = exeS.take().get();
            //exe.shutdownNow();

            return result;
        } catch (InterruptedException e) {
            e.printStackTrace();
            LOG.error(e);
        } catch (ExecutionException e) {
            e.printStackTrace();
            LOG.error(e);
        }
        return null;

    }

    public void shutDown() {
        exe.shutdown();
    }

    public static class ResultWrapper<T> {
        public Boolean isPrimary;
        public T t;

        public ResultWrapper(Boolean isPrimary, T t) {
            this.isPrimary = isPrimary;
            this.t = t;
        }
    }

}