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A driver for Apache Cassandra 1.2+ that works exclusively with the Cassandra Query Language version 3
(CQL3) and Cassandra's binary protocol.
/*
* Copyright (C) 2012-2017 DataStax 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.datastax.driver.core;
import com.google.common.base.Function;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.Uninterruptibles;
import io.netty.util.concurrent.EventExecutor;
import java.nio.ByteBuffer;
import java.util.Map;
import java.util.concurrent.ExecutionException;
/**
* Abstract implementation of the Session interface.
*
* This is primarly intended to make mocking easier.
*/
public abstract class AbstractSession implements Session {
private static final boolean CHECK_IO_DEADLOCKS = SystemProperties.getBoolean(
"com.datastax.driver.CHECK_IO_DEADLOCKS", true);
/**
* {@inheritDoc}
*/
@Override
public ResultSet execute(String query) {
return execute(new SimpleStatement(query));
}
/**
* {@inheritDoc}
*/
@Override
public ResultSet execute(String query, Object... values) {
return execute(new SimpleStatement(query, values));
}
/**
* {@inheritDoc}
*/
@Override
public ResultSet execute(String query, Map values) {
return execute(new SimpleStatement(query, values));
}
/**
* {@inheritDoc}
*/
@Override
public ResultSet execute(Statement statement) {
checkNotInEventLoop();
return executeAsync(statement).getUninterruptibly();
}
/**
* {@inheritDoc}
*/
@Override
public ResultSetFuture executeAsync(String query) {
return executeAsync(new SimpleStatement(query));
}
/**
* {@inheritDoc}
*/
@Override
public ResultSetFuture executeAsync(String query, Map values) {
return executeAsync(new SimpleStatement(query, values));
}
/**
* {@inheritDoc}
*/
@Override
public ResultSetFuture executeAsync(String query, Object... values) {
return executeAsync(new SimpleStatement(query, values));
}
/**
* {@inheritDoc}
*/
@Override
public PreparedStatement prepare(String query) {
checkNotInEventLoop();
try {
return Uninterruptibles.getUninterruptibly(prepareAsync(query));
} catch (ExecutionException e) {
throw DriverThrowables.propagateCause(e);
}
}
/**
* {@inheritDoc}
*/
@Override
public PreparedStatement prepare(RegularStatement statement) {
checkNotInEventLoop();
try {
return Uninterruptibles.getUninterruptibly(prepareAsync(statement));
} catch (ExecutionException e) {
throw DriverThrowables.propagateCause(e);
}
}
/**
* {@inheritDoc}
*/
@Override
public ListenableFuture prepareAsync(String query) {
return prepareAsync(query, null);
}
/**
* {@inheritDoc}
*/
@Override
public ListenableFuture prepareAsync(final RegularStatement statement) {
if (statement.hasValues())
throw new IllegalArgumentException("A statement to prepare should not have values");
final CodecRegistry codecRegistry = getCluster().getConfiguration().getCodecRegistry();
ListenableFuture prepared = prepareAsync(statement.getQueryString(codecRegistry), statement.getOutgoingPayload());
return Futures.transform(prepared, new Function() {
@Override
public PreparedStatement apply(PreparedStatement prepared) {
ProtocolVersion protocolVersion = getCluster().getConfiguration().getProtocolOptions().getProtocolVersion();
ByteBuffer routingKey = statement.getRoutingKey(protocolVersion, codecRegistry);
if (routingKey != null)
prepared.setRoutingKey(routingKey);
if (statement.getConsistencyLevel() != null)
prepared.setConsistencyLevel(statement.getConsistencyLevel());
if (statement.getSerialConsistencyLevel() != null)
prepared.setSerialConsistencyLevel(statement.getSerialConsistencyLevel());
if (statement.isTracing())
prepared.enableTracing();
prepared.setRetryPolicy(statement.getRetryPolicy());
prepared.setOutgoingPayload(statement.getOutgoingPayload());
prepared.setIdempotent(statement.isIdempotent());
return prepared;
}
});
}
/**
* Prepares the provided query string asynchronously,
* sending along the provided custom payload, if any.
*
* @param query the CQL query string to prepare
* @param customPayload the custom payload to send along the query, or {@code null} if no payload is to be sent
* @return a future on the prepared statement corresponding to {@code query}.
*/
protected abstract ListenableFuture prepareAsync(String query, Map customPayload);
/**
* {@inheritDoc}
*/
@Override
public void close() {
try {
closeAsync().get();
} catch (ExecutionException e) {
throw DriverThrowables.propagateCause(e);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
}
/**
* Checks that the current thread is not one of the Netty I/O threads used by the driver.
*
* This method is called from all the synchronous methods of this class to prevent deadlock issues.
*
* User code extending this class can also call this method at any time to check if any code
* making blocking calls is being wrongly executed on a Netty I/O thread.
*
* Note that the check performed by this method has a small overhead; if
* that is an issue, checks can be disabled by setting the System property
* {@code com.datastax.driver.CHECK_IO_DEADLOCKS} to {@code false}.
*
* @throws IllegalStateException if the current thread is one of the Netty I/O thread used by the driver.
*/
public void checkNotInEventLoop() {
Connection.Factory connectionFactory = getCluster().manager.connectionFactory;
if (!CHECK_IO_DEADLOCKS || connectionFactory == null)
return;
for (EventExecutor executor : connectionFactory.eventLoopGroup) {
if (executor.inEventLoop()) {
throw new IllegalStateException(
"Detected a synchronous call on an I/O thread, this can cause deadlocks or unpredictable " +
"behavior. This generally happens when a Future callback calls a synchronous Session " +
"method (execute() or prepare()), or iterates a result set past the fetch size " +
"(causing an internal synchronous fetch of the next page of results). " +
"Avoid this in your callbacks, or schedule them on a different executor.");
}
}
}
}