org.springframework.data.cassandra.core.cql.session.DefaultBridgedReactiveSession Maven / Gradle / Ivy
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/*
* Copyright 2017-2019 the original author or authors.
*
* 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 org.springframework.data.cassandra.core.cql.session;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutionException;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import reactor.core.publisher.MonoProcessor;
import reactor.core.publisher.MonoSink;
import reactor.core.scheduler.Scheduler;
import org.springframework.data.cassandra.ReactiveResultSet;
import org.springframework.data.cassandra.ReactiveSession;
import org.springframework.util.Assert;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.datastax.driver.core.Cluster;
import com.datastax.driver.core.ColumnDefinitions;
import com.datastax.driver.core.ExecutionInfo;
import com.datastax.driver.core.PreparedStatement;
import com.datastax.driver.core.RegularStatement;
import com.datastax.driver.core.ResultSet;
import com.datastax.driver.core.Row;
import com.datastax.driver.core.Session;
import com.datastax.driver.core.SimpleStatement;
import com.datastax.driver.core.Statement;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
/**
* Default implementation of a {@link ReactiveSession}. This implementation bridges asynchronous {@link Session} methods
* to reactive execution patterns.
*
* Calls are deferred until a subscriber subscribes to the resulting {@link org.reactivestreams.Publisher}. The calls
* are executed by subscribing to {@link ListenableFuture} and returning the result as calls complete.
*
* Elements are emitted on netty EventLoop threads. {@link ResultSet} allows {@link ResultSet#fetchMoreResults()
* asynchronous requesting} of subsequent pages. The next page is requested after emitting all elements of the previous
* page. However, this is an intermediate solution until Datastax can provide a fully reactive driver.
*
* All CQL operations performed by this class are logged at debug level, using
* {@code org.springframework.data.cassandra.core.cql.DefaultBridgedReactiveSession} as log category.
*
*
* @author Mark Paluch
* @since 2.0
* @see Mono
* @see ReactiveResultSet
* @see Scheduler
* @see ReactiveSession
*/
public class DefaultBridgedReactiveSession implements ReactiveSession {
private final Logger logger = LoggerFactory.getLogger(getClass());
private final Session session;
/**
* Create a new {@link DefaultBridgedReactiveSession} for a {@link Session}.
*
* @param session must not be {@literal null}.
* @since 2.1
*/
public DefaultBridgedReactiveSession(Session session) {
Assert.notNull(session, "Session must not be null");
this.session = session;
}
/**
* Create a new {@link DefaultBridgedReactiveSession} for a {@link Session} and {@link Scheduler}.
*
* @param session must not be {@literal null}.
* @param scheduler must not be {@literal null}.
* @deprecated since 2.1. Use {@link #DefaultBridgedReactiveSession(Session)} as a {@link Scheduler} is no longer
* required to off-load {@link ResultSet}'s blocking behavior.
*/
@Deprecated
public DefaultBridgedReactiveSession(Session session, Scheduler scheduler) {
this(session);
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.ReactiveSession#isClosed()
*/
@Override
public boolean isClosed() {
return this.session.isClosed();
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.ReactiveSession#getCluster()
*/
@Override
public Cluster getCluster() {
return this.session.getCluster();
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.ReactiveSession#execute(java.lang.String)
*/
@Override
public Mono execute(String query) {
Assert.hasText(query, "Query must not be empty");
return execute(new SimpleStatement(query));
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.ReactiveSession#execute(java.lang.String, java.lang.Object[])
*/
@Override
public Mono execute(String query, Object... values) {
Assert.hasText(query, "Query must not be empty");
return execute(new SimpleStatement(query, values));
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.ReactiveSession#execute(java.lang.String, java.util.Map)
*/
@Override
public Mono execute(String query, Map values) {
Assert.hasText(query, "Query must not be empty");
return execute(new SimpleStatement(query, values));
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.ReactiveSession#execute(com.datastax.driver.core.Statement)
*/
@Override
public Mono execute(Statement statement) {
Assert.notNull(statement, "Statement must not be null");
return Mono.create(sink -> {
try {
if (logger.isDebugEnabled()) {
logger.debug("Executing Statement [{}]", statement);
}
ListenableFuture future = this.session.executeAsync(statement);
ListenableFuture resultSetFuture =
Futures.transform(future, DefaultReactiveResultSet::new);
adaptFuture(resultSetFuture, sink);
}
catch (Exception cause) {
sink.error(cause);
}
});
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.ReactiveSession#prepare(java.lang.String)
*/
@Override
public Mono prepare(String query) {
Assert.hasText(query, "Query must not be empty");
return prepare(new SimpleStatement(query));
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.ReactiveSession#prepare(com.datastax.driver.core.RegularStatement)
*/
@Override
public Mono prepare(RegularStatement statement) {
Assert.notNull(statement, "Statement must not be null");
return Mono.create(sink -> {
try {
if (logger.isDebugEnabled()) {
logger.debug("Preparing Statement [{}]", statement);
}
ListenableFuture resultSetFuture = this.session.prepareAsync(statement);
adaptFuture(resultSetFuture, sink);
}
catch (Exception cause) {
sink.error(cause);
}
});
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.ReactiveSession#close()
*/
@Override
public void close() {
this.session.close();
}
/**
* Adapt {@link ListenableFuture} signals (completion, error) and propagate these to {@link MonoSink}.
*
* @param future the originating future.
* @param sink the sink receiving signals.
*/
private static void adaptFuture(ListenableFuture future, MonoSink sink) {
future.addListener(() -> {
if (future.isDone()) {
try {
sink.success(future.get());
}
catch (ExecutionException cause) {
sink.error(cause.getCause());
}
catch (Exception cause) {
sink.error(cause);
}
}
}, Runnable::run);
}
static class DefaultReactiveResultSet implements ReactiveResultSet {
private final ResultSet resultSet;
DefaultReactiveResultSet(ResultSet resultSet) {
this.resultSet = resultSet;
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.ReactiveResultSet#rows()
*/
@Override
public Flux rows() {
return getRows(Mono.just(this.resultSet));
}
Flux getRows(Mono nextResults) {
return nextResults.flatMapMany(it -> {
Flux rows = toRows(it);
if (it.isFullyFetched()) {
return rows;
}
MonoProcessor processor = MonoProcessor.create();
return rows
.doOnComplete(() -> fetchMore(it.fetchMoreResults(), processor))
.concatWith(getRows(processor));
});
}
static Flux toRows(ResultSet resultSet) {
int prefetch = Math.max(1, resultSet.getAvailableWithoutFetching());
return Flux.fromIterable(resultSet).take(prefetch);
}
static void fetchMore(ListenableFuture future, MonoProcessor sink) {
try {
future.addListener(() -> {
try {
sink.onNext(future.get());
sink.onComplete();
}
catch (ExecutionException cause) {
sink.onError(cause.getCause());
}
catch (Exception cause) {
sink.onError(cause);
}
}, Runnable::run);
}
catch (Exception cause) {
sink.onError(cause);
}
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.ReactiveResultSet#getColumnDefinitions()
*/
@Override
public ColumnDefinitions getColumnDefinitions() {
return this.resultSet.getColumnDefinitions();
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.ReactiveResultSet#wasApplied()
*/
@Override
public boolean wasApplied() {
return this.resultSet.wasApplied();
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.ReactiveResultSet#getExecutionInfo()
*/
@Override
public ExecutionInfo getExecutionInfo() {
return this.resultSet.getExecutionInfo();
}
/* (non-Javadoc)
* @see org.springframework.data.cassandra.ReactiveResultSet#getAllExecutionInfo()
*/
@Override
public List getAllExecutionInfo() {
return this.resultSet.getAllExecutionInfo();
}
}
}