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JdbcMapper
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Code Issues Releases Wiki Activity

QueryRunner.runRetry and runRetryFuture methods

Browse Source
pull/2/head
Travis Burtrum 6 years ago
parent a22109f31c
commit 8400ed3d00
2 changed files with 174 additions and 11 deletions
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169
common/src/main/java/com/moparisthebest/jdbc/QueryRunner.java
Unescape Escape View File

@ -3,6 +3,7 @@ package com.moparisthebest.jdbc;
import com.moparisthebest.jdbc.codegen.JdbcMapper;
import java.sql.SQLException;
import java.util.concurrent.*;
import static com.moparisthebest.jdbc.TryClose.tryClose;
@ -12,16 +13,56 @@ import static com.moparisthebest.jdbc.TryClose.tryClose;
*/
public class QueryRunner<T extends JdbcMapper> {
private static final int defaultRetryCount = 10;
private static final DelayStrategy defaultDelayStrategy = new ExponentialBackoff();
private static final ExecutorService defaultExecutorService = Executors.newCachedThreadPool(); // todo: good or bad default?
private final Factory<T> factory;
private final DelayStrategy delayStrategy;
private final int retryCount;
private final ExecutorService executorService;
public QueryRunner(final Factory<T> factory) {
if(factory == null)
public QueryRunner(final Factory<T> factory, final DelayStrategy delayStrategy, final ExecutorService executorService, final int retryCount) {
if (factory == null)
throw new NullPointerException("factory must be non-null");
if (delayStrategy == null)
throw new NullPointerException("delayStrategy must be non-null");
if (executorService == null)
throw new NullPointerException("executorService must be non-null");
if (retryCount < 1)
throw new IllegalArgumentException("retryCount must be > 0");
this.factory = factory;
this.delayStrategy = delayStrategy;
this.retryCount = retryCount;
this.executorService = Executors.newSingleThreadExecutor();
}
public QueryRunner(final Factory<T> factory) {
this(factory, defaultDelayStrategy, defaultExecutorService, defaultRetryCount);
}
public QueryRunner(final Factory<T> factory, final DelayStrategy delayStrategy) {
this(factory, delayStrategy, defaultExecutorService, defaultRetryCount);
}
public QueryRunner(final Factory<T> factory, final int retryCount) {
this(factory, defaultDelayStrategy, defaultExecutorService, retryCount);
}
public QueryRunner(final Factory<T> factory, final ExecutorService executorService) {
this(factory, defaultDelayStrategy, executorService, defaultRetryCount);
}
public QueryRunner(final Factory<T> factory, final DelayStrategy delayStrategy, final ExecutorService executorService) {
this(factory, delayStrategy, executorService, defaultRetryCount);
}
public QueryRunner(final Factory<T> factory, final ExecutorService executorService, final int retryCount) {
this(factory, defaultDelayStrategy, executorService, retryCount);
}
public <E> E run(final Runner<T, E> query) throws SQLException {
if(query == null)
if (query == null)
throw new NullPointerException("query must be non-null");
T dao = null;
try {
@ -33,7 +74,7 @@ public class QueryRunner<T extends JdbcMapper> {
}
public <E> E runInTransaction(final Runner<T, E> query) throws SQLException {
if(query == null)
if (query == null)
throw new NullPointerException("query must be non-null");
T dao = null;
try {
@ -46,20 +87,20 @@ public class QueryRunner<T extends JdbcMapper> {
if (dao != null) {
try {
dao.getConnection().rollback();
} catch(SQLException excep) {
} catch (SQLException excep) {
// ignore to throw original
}
}
if(e instanceof SQLException)
if (e instanceof SQLException)
throw (SQLException) e;
if(e instanceof RuntimeException)
if (e instanceof RuntimeException)
throw (RuntimeException) e;
throw new RuntimeException("odd error should never happen", e);
} finally {
if (dao != null) {
try {
dao.getConnection().setAutoCommit(true);
} catch(SQLException excep) {
} catch (SQLException excep) {
// ignore
}
tryClose(dao);
@ -67,7 +108,119 @@ public class QueryRunner<T extends JdbcMapper> {
}
}
public <E> E runRetry(final Runner<T, E> query) throws SQLException {
SQLException lastException = null;
int x = 0;
do {
try {
return runInTransaction(query);
} catch (SQLException e) {
lastException = e;
try {
Thread.sleep(delayStrategy.getDelay(x));
} catch (InterruptedException e2) {
Thread.interrupted();
}
}
} while (++x <= retryCount);
throw lastException;
}
public <E> Future<E> runRetryFuture(final Runner<T, E> query) {
// todo: sleeps in thread, could use ScheduledExecutorService maybe?
return executorService.submit(new Callable<E>() {
@Override
public E call() throws Exception {
return runRetry(query);
}
});
}
public static interface Runner<T, E> {
E run(T dao) throws SQLException;
}
public static interface DelayStrategy {
long getDelay(int attempt);
}
public static DelayStrategy exponentialBackoff() {
return defaultDelayStrategy;
}
public static DelayStrategy exponentialBackoff(long minBackoff, long maxBackoff, long slotTime) {
return new ExponentialBackoff(minBackoff, maxBackoff, slotTime);
}
public static DelayStrategy fixedDelay(long delay) {
return new FixedDelay(delay);
}
public static DelayStrategy incrementalDelay(long initialInterval, long incrementalInterval) {
return new IncrementalDelay(initialInterval, incrementalInterval);
}
/**
* Implements truncated binary exponential backoff to calculate retry delay per
* IEEE 802.3-2008 Section 1. There will be at most ten (10) contention periods
* of backoff, each contention period whose amount is equal to the delta backoff.
*
* @author Robert Buck (buck.robert.j@gmail.com)
*/
private static class ExponentialBackoff implements DelayStrategy {
public static final long DEFAULT_MIN_BACKOFF = TimeUnit.MILLISECONDS.convert(1, TimeUnit.SECONDS);
public static final long DEFAULT_MAX_BACKOFF = TimeUnit.MILLISECONDS.convert(30, TimeUnit.SECONDS);
public static final long DEFAULT_SLOT_TIME = TimeUnit.MILLISECONDS.convert(2, TimeUnit.SECONDS);
private final long minBackoff;
private final long maxBackoff;
private final long slotTime;
private ExponentialBackoff() {
this(DEFAULT_MIN_BACKOFF, DEFAULT_MAX_BACKOFF, DEFAULT_SLOT_TIME);
}
private ExponentialBackoff(long minBackoff, long maxBackoff, long slotTime) {
this.minBackoff = minBackoff;
this.maxBackoff = maxBackoff;
this.slotTime = slotTime;
}
@Override
public long getDelay(final int retryCount) {
final int MAX_CONTENTION_PERIODS = 10;
return retryCount == 0 ? 0 : Math.min(minBackoff + ThreadLocalRandom.current().nextInt(2 << Math.min(retryCount, MAX_CONTENTION_PERIODS - 1)) * slotTime, maxBackoff);
}
}
private static class FixedDelay implements DelayStrategy {
private final long delay;
private FixedDelay(final long delay) {
this.delay = delay;
}
@Override
public long getDelay(final int attempt) {
return delay;
}
}
private static class IncrementalDelay implements DelayStrategy {
private final long initialInterval;
private final long incrementalInterval;
private IncrementalDelay(long initialInterval, long incrementalInterval) {
this.initialInterval = initialInterval;
this.incrementalInterval = incrementalInterval;
}
@Override
public long getDelay(final int attempt) {
return initialInterval + incrementalInterval * attempt;
}
}
}

16
querymapper/src/test/java/com/moparisthebest/jdbc/QueryRunnerTest.java
Unescape Escape View File

@ -19,15 +19,25 @@ public class QueryRunnerTest {
public Connection create() throws SQLException {
return QueryMapperTest.getConnection();
}
}));
}), QueryRunner.fixedDelay(5));
private void testPerson(final Person expected, final String query) throws Throwable {
final Person actual = qr.runInTransaction(new QueryRunner.Runner<QueryMapper, Person>() {
final Person actual =
//qr.run(
//qr.runRetry(
qr.runRetryFuture(
new QueryRunner.Runner<QueryMapper, Person>() {
@Override
public Person run(final QueryMapper qm) throws SQLException {
if(Math.random() < 0.5) {
System.out.println("fake fail");
throw new SQLException("fake 50% failure rate");
}
return qm.toObject(query, expected.getClass(), expected.getPersonNo());
}
});
})
.get()
;
/*
System.out.println("expected: " + expected);
System.out.println("actual: " + actual);

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