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https://github.com/moparisthebest/JdbcMapper
synced 2024-11-24 18:02:18 -05:00
QueryRunner.runRetry and runRetryFuture methods
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a22109f31c
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@ -3,6 +3,7 @@ package com.moparisthebest.jdbc;
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import com.moparisthebest.jdbc.codegen.JdbcMapper;
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import java.sql.SQLException;
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import java.util.concurrent.*;
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import static com.moparisthebest.jdbc.TryClose.tryClose;
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@ -12,12 +13,52 @@ import static com.moparisthebest.jdbc.TryClose.tryClose;
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*/
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public class QueryRunner<T extends JdbcMapper> {
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private final Factory<T> factory;
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private static final int defaultRetryCount = 10;
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private static final DelayStrategy defaultDelayStrategy = new ExponentialBackoff();
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private static final ExecutorService defaultExecutorService = Executors.newCachedThreadPool(); // todo: good or bad default?
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public QueryRunner(final Factory<T> factory) {
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private final Factory<T> factory;
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private final DelayStrategy delayStrategy;
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private final int retryCount;
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private final ExecutorService executorService;
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public QueryRunner(final Factory<T> factory, final DelayStrategy delayStrategy, final ExecutorService executorService, final int retryCount) {
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if (factory == null)
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throw new NullPointerException("factory must be non-null");
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if (delayStrategy == null)
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throw new NullPointerException("delayStrategy must be non-null");
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if (executorService == null)
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throw new NullPointerException("executorService must be non-null");
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if (retryCount < 1)
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throw new IllegalArgumentException("retryCount must be > 0");
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this.factory = factory;
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this.delayStrategy = delayStrategy;
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this.retryCount = retryCount;
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this.executorService = Executors.newSingleThreadExecutor();
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}
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public QueryRunner(final Factory<T> factory) {
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this(factory, defaultDelayStrategy, defaultExecutorService, defaultRetryCount);
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}
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public QueryRunner(final Factory<T> factory, final DelayStrategy delayStrategy) {
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this(factory, delayStrategy, defaultExecutorService, defaultRetryCount);
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}
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public QueryRunner(final Factory<T> factory, final int retryCount) {
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this(factory, defaultDelayStrategy, defaultExecutorService, retryCount);
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}
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public QueryRunner(final Factory<T> factory, final ExecutorService executorService) {
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this(factory, defaultDelayStrategy, executorService, defaultRetryCount);
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}
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public QueryRunner(final Factory<T> factory, final DelayStrategy delayStrategy, final ExecutorService executorService) {
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this(factory, delayStrategy, executorService, defaultRetryCount);
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}
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public QueryRunner(final Factory<T> factory, final ExecutorService executorService, final int retryCount) {
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this(factory, defaultDelayStrategy, executorService, retryCount);
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}
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public <E> E run(final Runner<T, E> query) throws SQLException {
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@ -67,7 +108,119 @@ public class QueryRunner<T extends JdbcMapper> {
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}
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}
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public <E> E runRetry(final Runner<T, E> query) throws SQLException {
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SQLException lastException = null;
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int x = 0;
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do {
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try {
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return runInTransaction(query);
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} catch (SQLException e) {
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lastException = e;
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try {
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Thread.sleep(delayStrategy.getDelay(x));
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} catch (InterruptedException e2) {
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Thread.interrupted();
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}
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}
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} while (++x <= retryCount);
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throw lastException;
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}
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public <E> Future<E> runRetryFuture(final Runner<T, E> query) {
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// todo: sleeps in thread, could use ScheduledExecutorService maybe?
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return executorService.submit(new Callable<E>() {
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@Override
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public E call() throws Exception {
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return runRetry(query);
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}
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});
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}
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public static interface Runner<T, E> {
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E run(T dao) throws SQLException;
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}
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public static interface DelayStrategy {
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long getDelay(int attempt);
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}
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public static DelayStrategy exponentialBackoff() {
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return defaultDelayStrategy;
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}
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public static DelayStrategy exponentialBackoff(long minBackoff, long maxBackoff, long slotTime) {
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return new ExponentialBackoff(minBackoff, maxBackoff, slotTime);
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}
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public static DelayStrategy fixedDelay(long delay) {
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return new FixedDelay(delay);
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}
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public static DelayStrategy incrementalDelay(long initialInterval, long incrementalInterval) {
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return new IncrementalDelay(initialInterval, incrementalInterval);
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}
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/**
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* Implements truncated binary exponential backoff to calculate retry delay per
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* IEEE 802.3-2008 Section 1. There will be at most ten (10) contention periods
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* of backoff, each contention period whose amount is equal to the delta backoff.
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*
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* @author Robert Buck (buck.robert.j@gmail.com)
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*/
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private static class ExponentialBackoff implements DelayStrategy {
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public static final long DEFAULT_MIN_BACKOFF = TimeUnit.MILLISECONDS.convert(1, TimeUnit.SECONDS);
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public static final long DEFAULT_MAX_BACKOFF = TimeUnit.MILLISECONDS.convert(30, TimeUnit.SECONDS);
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public static final long DEFAULT_SLOT_TIME = TimeUnit.MILLISECONDS.convert(2, TimeUnit.SECONDS);
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private final long minBackoff;
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private final long maxBackoff;
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private final long slotTime;
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private ExponentialBackoff() {
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this(DEFAULT_MIN_BACKOFF, DEFAULT_MAX_BACKOFF, DEFAULT_SLOT_TIME);
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}
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private ExponentialBackoff(long minBackoff, long maxBackoff, long slotTime) {
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this.minBackoff = minBackoff;
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this.maxBackoff = maxBackoff;
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this.slotTime = slotTime;
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}
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@Override
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public long getDelay(final int retryCount) {
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final int MAX_CONTENTION_PERIODS = 10;
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return retryCount == 0 ? 0 : Math.min(minBackoff + ThreadLocalRandom.current().nextInt(2 << Math.min(retryCount, MAX_CONTENTION_PERIODS - 1)) * slotTime, maxBackoff);
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}
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}
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private static class FixedDelay implements DelayStrategy {
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private final long delay;
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private FixedDelay(final long delay) {
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this.delay = delay;
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}
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@Override
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public long getDelay(final int attempt) {
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return delay;
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}
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}
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private static class IncrementalDelay implements DelayStrategy {
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private final long initialInterval;
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private final long incrementalInterval;
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private IncrementalDelay(long initialInterval, long incrementalInterval) {
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this.initialInterval = initialInterval;
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this.incrementalInterval = incrementalInterval;
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}
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@Override
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public long getDelay(final int attempt) {
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return initialInterval + incrementalInterval * attempt;
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}
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}
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}
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@ -19,15 +19,25 @@ public class QueryRunnerTest {
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public Connection create() throws SQLException {
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return QueryMapperTest.getConnection();
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}
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}));
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}), QueryRunner.fixedDelay(5));
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private void testPerson(final Person expected, final String query) throws Throwable {
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final Person actual = qr.runInTransaction(new QueryRunner.Runner<QueryMapper, Person>() {
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final Person actual =
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//qr.run(
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//qr.runRetry(
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qr.runRetryFuture(
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new QueryRunner.Runner<QueryMapper, Person>() {
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@Override
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public Person run(final QueryMapper qm) throws SQLException {
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if(Math.random() < 0.5) {
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System.out.println("fake fail");
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throw new SQLException("fake 50% failure rate");
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}
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return qm.toObject(query, expected.getClass(), expected.getPersonNo());
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}
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});
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})
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.get()
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;
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/*
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System.out.println("expected: " + expected);
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System.out.println("actual: " + actual);
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