/*
* Copyright (C) 2012-2015 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.datastax.driver.core.Message.Response;
import com.datastax.driver.core.exceptions.DriverInternalError;
import com.datastax.driver.core.exceptions.InvalidQueryException;
import com.datastax.driver.core.exceptions.UnsupportedFeatureException;
import com.datastax.driver.core.exceptions.UnsupportedProtocolVersionException;
import com.datastax.driver.core.policies.LoadBalancingPolicy;
import com.datastax.driver.core.policies.ReconnectionPolicy;
import com.datastax.driver.core.policies.SpeculativeExecutionPolicy;
import com.datastax.driver.core.utils.MoreFutures;
import com.google.common.base.Functions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import com.google.common.util.concurrent.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;
/**
* Driver implementation of the Session interface.
*/
class SessionManager extends AbstractSession {
private static final Logger logger = LoggerFactory.getLogger(Session.class);
final Cluster cluster;
final ConcurrentMap<Host, HostConnectionPool> pools;
final HostConnectionPool.PoolState poolsState;
private final AtomicReference<ListenableFuture<Session>> initFuture = new AtomicReference<ListenableFuture<Session>>();
final AtomicReference<CloseFuture> closeFuture = new AtomicReference<CloseFuture>();
private volatile boolean isInit;
private volatile boolean isClosing;
// Package protected, only Cluster should construct that.
SessionManager(Cluster cluster) {
this.cluster = cluster;
this.pools = new ConcurrentHashMap<Host, HostConnectionPool>();
this.poolsState = new HostConnectionPool.PoolState();
}
@Override
public Session init() {
try {
return Uninterruptibles.getUninterruptibly(initAsync());
} catch (ExecutionException e) {
throw DriverThrowables.propagateCause(e);
}
}
@Override
public ListenableFuture<Session> initAsync() {
// If we haven't initialized the cluster, do it now
cluster.init();
ListenableFuture<Session> existing = initFuture.get();
if (existing != null)
return existing;
final SettableFuture<Session> myInitFuture = SettableFuture.create();
if (!initFuture.compareAndSet(null, myInitFuture))
return initFuture.get();
Collection<Host> hosts = cluster.getMetadata().allHosts();
ListenableFuture<?> allPoolsCreatedFuture = createPools(hosts);
ListenableFuture<?> allPoolsUpdatedFuture = GuavaCompatibility.INSTANCE.transformAsync(allPoolsCreatedFuture,
new AsyncFunction<Object, Object>() {
@Override
@SuppressWarnings("unchecked")
public ListenableFuture<Object> apply(Object input) throws Exception {
isInit = true;
return (ListenableFuture<Object>) updateCreatedPools();
}
});
Futures.addCallback(allPoolsUpdatedFuture, new FutureCallback<Object>() {
@Override
public void onSuccess(Object result) {
myInitFuture.set(SessionManager.this);
}
@Override
public void onFailure(Throwable t) {
SessionManager.this.closeAsync(); // don't leak the session
myInitFuture.setException(t);
}
});
return myInitFuture;
}
private ListenableFuture<?> createPools(Collection<Host> hosts) {
List<ListenableFuture<Boolean>> futures = Lists.newArrayListWithCapacity(hosts.size());
for (Host host : hosts)
if (host.state != Host.State.DOWN)
futures.add(maybeAddPool(host, null));
return Futures.allAsList(futures);
}
@Override
public String getLoggedKeyspace() {
return poolsState.keyspace;
}
@Override
public ResultSetFuture executeAsync(final Statement statement) {
if (isInit) {
DefaultResultSetFuture future = new DefaultResultSetFuture(this, cluster.manager.protocolVersion(), makeRequestMessage(statement, null));
new RequestHandler(this, future, statement).sendRequest();
return future;
} else {
// If the session is not initialized, we can't call makeRequestMessage() synchronously, because it
// requires internal Cluster state that might not be initialized yet (like the protocol version).
// Because of the way the future is built, we need another 'proxy' future that we can return now.
final ChainedResultSetFuture chainedFuture = new ChainedResultSetFuture();
this.initAsync().addListener(new Runnable() {
@Override
public void run() {
DefaultResultSetFuture actualFuture = new DefaultResultSetFuture(SessionManager.this, cluster.manager.protocolVersion(), makeRequestMessage(statement, null));
execute(actualFuture, statement);
chainedFuture.setSource(actualFuture);
}
}, executor());
return chainedFuture;
}
}
@Override
protected ListenableFuture<PreparedStatement> prepareAsync(String query, Map<String, ByteBuffer> customPayload) {
Requests.Prepare request = new Requests.Prepare(query);
request.setCustomPayload(customPayload);
Connection.Future future = new Connection.Future(request);
execute(future, Statement.DEFAULT);
return toPreparedStatement(query, future);
}
@Override
public CloseFuture closeAsync() {
CloseFuture future = closeFuture.get();
if (future != null)
return future;
isClosing = true;
cluster.manager.removeSession(this);
List<CloseFuture> futures = new ArrayList<CloseFuture>(pools.size());
for (HostConnectionPool pool : pools.values())
futures.add(pool.closeAsync());
future = new CloseFuture.Forwarding(futures);
return closeFuture.compareAndSet(null, future)
? future
: closeFuture.get(); // We raced, it's ok, return the future that was actually set
}
@Override
public boolean isClosed() {
return closeFuture.get() != null;
}
@Override
public Cluster getCluster() {
return cluster;
}
@Override
public Session.State getState() {
return new State(this);
}
private ListenableFuture<PreparedStatement> toPreparedStatement(final String query, final Connection.Future future) {
return GuavaCompatibility.INSTANCE.transformAsync(future, new AsyncFunction<Response, PreparedStatement>() {
@Override
public ListenableFuture<PreparedStatement> apply(Response response) {
switch (response.type) {
case RESULT:
Responses.Result rm = (Responses.Result) response;
switch (rm.kind) {
case PREPARED:
Responses.Result.Prepared pmsg = (Responses.Result.Prepared) rm;
PreparedStatement stmt = DefaultPreparedStatement.fromMessage(pmsg, cluster, query, poolsState.keyspace);
stmt = cluster.manager.addPrepared(stmt);
if (cluster.getConfiguration().getQueryOptions().isPrepareOnAllHosts()) {
// All Sessions are connected to the same nodes so it's enough to prepare only the nodes of this session.
// If that changes, we'll have to make sure this propagate to other sessions too.
return prepare(stmt, future.getAddress());
} else {
return Futures.immediateFuture(stmt);
}
default:
return Futures.immediateFailedFuture(
new DriverInternalError(String.format("%s response received when prepared statement was expected", rm.kind)));
}
case ERROR:
return Futures.immediateFailedFuture(
((Responses.Error) response).asException(future.getAddress()));
default:
return Futures.immediateFailedFuture(
new DriverInternalError(String.format("%s response received when prepared statement was expected", response.type)));
}
}
}, executor());
}
Connection.Factory connectionFactory() {
return cluster.manager.connectionFactory;
}
Configuration configuration() {
return cluster.manager.configuration;
}
LoadBalancingPolicy loadBalancingPolicy() {
return cluster.manager.loadBalancingPolicy();
}
SpeculativeExecutionPolicy speculativeExecutionPolicy() {
return cluster.manager.speculativeExecutionPolicy();
}
ReconnectionPolicy reconnectionPolicy() {
return cluster.manager.reconnectionPolicy();
}
ListeningExecutorService executor() {
return cluster.manager.executor;
}
ListeningExecutorService blockingExecutor() {
return cluster.manager.blockingExecutor;
}
// Returns whether there was problem creating the pool
ListenableFuture<Boolean> forceRenewPool(final Host host, Connection reusedConnection) {
final HostDistance distance = cluster.manager.loadBalancingPolicy().distance(host);
if (distance == HostDistance.IGNORED)
return Futures.immediateFuture(true);
if (isClosing)
return Futures.immediateFuture(false);
final HostConnectionPool newPool = new HostConnectionPool(host, distance, this);
ListenableFuture<Void> poolInitFuture = newPool.initAsync(reusedConnection);
final SettableFuture<Boolean> future = SettableFuture.create();
Futures.addCallback(poolInitFuture, new FutureCallback<Void>() {
@Override
public void onSuccess(Void result) {
HostConnectionPool previous = pools.put(host, newPool);
if (previous == null) {
logger.debug("Added connection pool for {}", host);
} else {
logger.debug("Renewed connection pool for {}", host);
previous.closeAsync();
}
// If we raced with a session shutdown, ensure that the pool will be closed.
if (isClosing) {
newPool.closeAsync();
pools.remove(host);
future.set(false);
} else {
future.set(true);
}
}
@Override
public void onFailure(Throwable t) {
logger.warn("Error creating pool to " + host, t);
future.set(false);
}
});
return future;
}
// Replace pool for a given host only if it's the given previous value (which can be null)
// This returns a future if the replacement was successful, or null if we raced.
private ListenableFuture<Void> replacePool(final Host host, HostDistance distance, HostConnectionPool previous, Connection reusedConnection) {
if (isClosing)
return MoreFutures.VOID_SUCCESS;
final HostConnectionPool newPool = new HostConnectionPool(host, distance, this);
if (previous == null) {
if (pools.putIfAbsent(host, newPool) != null) {
return null;
}
} else {
if (!pools.replace(host, previous, newPool)) {
return null;
}
if (!previous.isClosed()) {
logger.warn("Replacing a pool that wasn't closed. Closing it now, but this was not expected.");
previous.closeAsync();
}
}
ListenableFuture<Void> poolInitFuture = newPool.initAsync(reusedConnection);
Futures.addCallback(poolInitFuture, new FutureCallback<Void>() {
@Override
public void onSuccess(Void result) {
// If we raced with a session shutdown, ensure that the pool will be closed.
if (isClosing) {
newPool.closeAsync();
pools.remove(host);
}
}
@Override
public void onFailure(Throwable t) {
pools.remove(host);
}
});
return poolInitFuture;
}
// Returns whether there was problem creating the pool
ListenableFuture<Boolean> maybeAddPool(final Host host, Connection reusedConnection) {
final HostDistance distance = cluster.manager.loadBalancingPolicy().distance(host);
if (distance == HostDistance.IGNORED)
return Futures.immediateFuture(true);
HostConnectionPool previous = pools.get(host);
if (previous != null && !previous.isClosed())
return Futures.immediateFuture(true);
while (true) {
previous = pools.get(host);
if (previous != null && !previous.isClosed())
return Futures.immediateFuture(true);
final SettableFuture<Boolean> future = SettableFuture.create();
ListenableFuture<Void> newPoolInit = replacePool(host, distance, previous, reusedConnection);
if (newPoolInit != null) {
Futures.addCallback(newPoolInit, new FutureCallback<Void>() {
@Override
public void onSuccess(Void result) {
logger.debug("Added connection pool for {}", host);
future.set(true);
}
@Override
public void onFailure(Throwable t) {
if (t instanceof UnsupportedProtocolVersionException) {
cluster.manager.logUnsupportedVersionProtocol(host, ((UnsupportedProtocolVersionException) t).getUnsupportedVersion());
cluster.manager.triggerOnDown(host, false);
} else if (t instanceof ClusterNameMismatchException) {
ClusterNameMismatchException e = (ClusterNameMismatchException) t;
cluster.manager.logClusterNameMismatch(host, e.expectedClusterName, e.actualClusterName);
cluster.manager.triggerOnDown(host, false);
} else {
logger.warn("Error creating pool to " + host, t);
}
future.set(false);
}
});
return future;
}
}
}
CloseFuture removePool(Host host) {
final HostConnectionPool pool = pools.remove(host);
return pool == null
? CloseFuture.immediateFuture()
: pool.closeAsync();
}
/*
* When the set of live nodes change, the loadbalancer will change his
* mind on host distances. It might change it on the node that came/left
* but also on other nodes (for instance, if a node dies, another
* previously ignored node may be now considered).
*
* This method ensures that all hosts for which a pool should exist
* have one, and hosts that shouldn't don't.
*/
ListenableFuture<?> updateCreatedPools() {
// This method does nothing during initialization. Some hosts may be non-responsive but not yet marked DOWN; if
// we execute the code below we would try to create their pool over and over again.
// It's called explicitly at the end of init(), once isInit has been set to true.
if (!isInit)
return MoreFutures.VOID_SUCCESS;
// We do 2 iterations, so that we add missing pools first, and them remove all unecessary pool second.
// That way, we'll avoid situation where we'll temporarily lose connectivity
final List<Host> toRemove = new ArrayList<Host>();
List<ListenableFuture<Boolean>> poolCreatedFutures = Lists.newArrayList();
for (Host h : cluster.getMetadata().allHosts()) {
HostDistance dist = loadBalancingPolicy().distance(h);
HostConnectionPool pool = pools.get(h);
if (pool == null) {
if (dist != HostDistance.IGNORED && h.state == Host.State.UP)
poolCreatedFutures.add(maybeAddPool(h, null));
} else if (dist != pool.hostDistance) {
if (dist == HostDistance.IGNORED) {
toRemove.add(h);
} else {
pool.hostDistance = dist;
pool.ensureCoreConnections();
}
}
}
// Wait pool creation before removing, so we don't lose connectivity
ListenableFuture<?> allPoolsCreatedFuture = Futures.successfulAsList(poolCreatedFutures);
return GuavaCompatibility.INSTANCE.transformAsync(allPoolsCreatedFuture, new AsyncFunction<Object, List<Void>>() {
@Override
public ListenableFuture<List<Void>> apply(Object input) throws Exception {
List<ListenableFuture<Void>> poolRemovedFuture = Lists.newArrayListWithCapacity(toRemove.size());
for (Host h : toRemove)
poolRemovedFuture.add(removePool(h));
return Futures.successfulAsList(poolRemovedFuture);
}
});
}
void updateCreatedPools(Host h) {
HostDistance dist = loadBalancingPolicy().distance(h);
HostConnectionPool pool = pools.get(h);
try {
if (pool == null) {
if (dist != HostDistance.IGNORED && h.state == Host.State.UP)
try {
maybeAddPool(h, null).get();
} catch (ExecutionException e) {
// Ignore, maybeAddPool has already handled the error
}
} else if (dist != pool.hostDistance) {
if (dist == HostDistance.IGNORED) {
removePool(h).get();
} else {
pool.hostDistance = dist;
pool.ensureCoreConnections();
}
}
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
} catch (ExecutionException e) {
logger.error("Unexpected error while refreshing connection pools", e.getCause());
}
}
void onDown(Host host) throws InterruptedException, ExecutionException {
// Note that with well behaved balancing policy (that ignore dead nodes), the removePool call is not necessary
// since updateCreatedPools should take care of it. But better protect against non well behaving policies.
removePool(host).force().get();
updateCreatedPools().get();
}
void onRemove(Host host) throws InterruptedException, ExecutionException {
onDown(host);
}
Message.Request makeRequestMessage(Statement statement, ByteBuffer pagingState) {
// We need the protocol version, which is only available once the cluster has initialized. Initialize the session to ensure this is the case.
// init() locks, so avoid if we know we don't need it.
if (!isInit)
init();
ProtocolVersion protocolVersion = cluster.manager.protocolVersion();
CodecRegistry codecRegistry = cluster.manager.configuration.getCodecRegistry();
ConsistencyLevel consistency = statement.getConsistencyLevel();
if (consistency == null)
consistency = configuration().getQueryOptions().getConsistencyLevel();
ConsistencyLevel serialConsistency = statement.getSerialConsistencyLevel();
if (protocolVersion.compareTo(ProtocolVersion.V3) < 0 && statement instanceof BatchStatement) {
if (serialConsistency != null)
throw new UnsupportedFeatureException(protocolVersion, "Serial consistency on batch statements is not supported");
} else if (serialConsistency == null)
serialConsistency = configuration().getQueryOptions().getSerialConsistencyLevel();
if (statement.getOutgoingPayload() != null && protocolVersion.compareTo(ProtocolVersion.V4) < 0)
throw new UnsupportedFeatureException(protocolVersion, "Custom payloads are only supported since native protocol V4");
long defaultTimestamp = Long.MIN_VALUE;
if (protocolVersion.compareTo(ProtocolVersion.V3) >= 0) {
defaultTimestamp = statement.getDefaultTimestamp();
if (defaultTimestamp == Long.MIN_VALUE)
defaultTimestamp = cluster.getConfiguration().getPolicies().getTimestampGenerator().next();
}
int fetchSize = statement.getFetchSize();
ByteBuffer usedPagingState = pagingState;
if (protocolVersion == ProtocolVersion.V1) {
assert pagingState == null;
// We don't let the user change the fetchSize globally if the proto v1 is used, so we just need to
// check for the case of a per-statement override
if (fetchSize <= 0)
fetchSize = -1;
else if (fetchSize != Integer.MAX_VALUE)
throw new UnsupportedFeatureException(protocolVersion, "Paging is not supported");
} else if (fetchSize <= 0) {
fetchSize = configuration().getQueryOptions().getFetchSize();
}
if (fetchSize == Integer.MAX_VALUE)
fetchSize = -1;
if (pagingState == null) {
usedPagingState = statement.getPagingState();
}
if (statement instanceof StatementWrapper)
statement = ((StatementWrapper) statement).getWrappedStatement();
Message.Request request;
if (statement instanceof RegularStatement) {
RegularStatement rs = (RegularStatement) statement;
// It saddens me that we special case for the query builder here, but for now this is simpler.
// We could provide a general API in RegularStatement instead at some point but it's unclear what's
// the cleanest way to do that is right now (and it's probably not really that useful anyway).
if (protocolVersion == ProtocolVersion.V1 && rs instanceof com.datastax.driver.core.querybuilder.BuiltStatement)
((com.datastax.driver.core.querybuilder.BuiltStatement) rs).setForceNoValues(true);
ByteBuffer[] rawPositionalValues = rs.getValues(protocolVersion, codecRegistry);
Map<String, ByteBuffer> rawNamedValues = rs.getNamedValues(protocolVersion, codecRegistry);
if (protocolVersion == ProtocolVersion.V1 && (rawPositionalValues != null || rawNamedValues != null))
throw new UnsupportedFeatureException(protocolVersion, "Binary values are not supported");
if (protocolVersion == ProtocolVersion.V2 && rawNamedValues != null)
throw new UnsupportedFeatureException(protocolVersion, "Named values are not supported");
List<ByteBuffer> positionalValues = rawPositionalValues == null ? Collections.<ByteBuffer>emptyList() : Arrays.asList(rawPositionalValues);
Map<String, ByteBuffer> namedValues = rawNamedValues == null ? Collections.<String, ByteBuffer>emptyMap() : rawNamedValues;
String qString = rs.getQueryString(codecRegistry);
Requests.QueryProtocolOptions options = new Requests.QueryProtocolOptions(Message.Request.Type.QUERY, consistency, positionalValues, namedValues,
false, fetchSize, usedPagingState, serialConsistency, defaultTimestamp);
request = new Requests.Query(qString, options, statement.isTracing());
} else if (statement instanceof BoundStatement) {
BoundStatement bs = (BoundStatement) statement;
if (!cluster.manager.preparedQueries.containsKey(bs.statement.getPreparedId().id)) {
throw new InvalidQueryException(String.format("Tried to execute unknown prepared query : %s. "
+ "You may have used a PreparedStatement that was created with another Cluster instance.", bs.statement.getPreparedId().id));
}
if (protocolVersion.compareTo(ProtocolVersion.V4) < 0)
bs.ensureAllSet();
boolean skipMetadata = protocolVersion != ProtocolVersion.V1 && bs.statement.getPreparedId().resultSetMetadata != null;
Requests.QueryProtocolOptions options = new Requests.QueryProtocolOptions(Message.Request.Type.EXECUTE, consistency, Arrays.asList(bs.wrapper.values), Collections.<String, ByteBuffer>emptyMap(),
skipMetadata, fetchSize, usedPagingState, serialConsistency, defaultTimestamp);
request = new Requests.Execute(bs.statement.getPreparedId().id, options, statement.isTracing());
} else {
assert statement instanceof BatchStatement : statement;
assert pagingState == null;
if (protocolVersion == ProtocolVersion.V1)
throw new UnsupportedFeatureException(protocolVersion, "Protocol level batching is not supported");
BatchStatement bs = (BatchStatement) statement;
if (protocolVersion.compareTo(ProtocolVersion.V4) < 0)
bs.ensureAllSet();
BatchStatement.IdAndValues idAndVals = bs.getIdAndValues(protocolVersion, codecRegistry);
Requests.BatchProtocolOptions options = new Requests.BatchProtocolOptions(consistency, serialConsistency, defaultTimestamp);
request = new Requests.Batch(bs.batchType, idAndVals.ids, idAndVals.values, options, statement.isTracing());
}
request.setCustomPayload(statement.getOutgoingPayload());
return request;
}
/**
* Execute the provided request.
* <p/>
* This method will find a suitable node to connect to using the
* {@link LoadBalancingPolicy} and handle host failover.
*/
void execute(final RequestHandler.Callback callback, final Statement statement) {
if (isInit)
new RequestHandler(this, callback, statement).sendRequest();
else
this.initAsync().addListener(new Runnable() {
@Override
public void run() {
new RequestHandler(SessionManager.this, callback, statement).sendRequest();
}
}, executor());
}
private ListenableFuture<PreparedStatement> prepare(final PreparedStatement statement, InetSocketAddress toExclude) {
final String query = statement.getQueryString();
List<ListenableFuture<Response>> futures = Lists.newArrayListWithExpectedSize(pools.size());
for (final Map.Entry<Host, HostConnectionPool> entry : pools.entrySet()) {
if (entry.getKey().getSocketAddress().equals(toExclude))
continue;
try {
// Preparing is not critical: if it fails, it will fix itself later when the user tries to execute
// the prepared query. So don't wait if no connection is available, simply abort.
ListenableFuture<Connection> connectionFuture = entry.getValue().borrowConnection(
0, TimeUnit.MILLISECONDS, 0);
ListenableFuture<Response> prepareFuture = GuavaCompatibility.INSTANCE.transformAsync(connectionFuture,
new AsyncFunction<Connection, Response>() {
@Override
public ListenableFuture<Response> apply(final Connection c) throws Exception {
Connection.Future responseFuture = c.write(new Requests.Prepare(query));
Futures.addCallback(responseFuture, new FutureCallback<Response>() {
@Override
public void onSuccess(Response result) {
c.release();
}
@Override
public void onFailure(Throwable t) {
logger.debug(String.format("Unexpected error while preparing query (%s) on %s",
query, entry.getKey()), t);
c.release();
}
});
return responseFuture;
}
});
futures.add(prepareFuture);
} catch (Exception e) {
// Again, not being able to prepare the query right now is no big deal, so just ignore
}
}
// Return the statement when all futures are done
return Futures.transform(
Futures.successfulAsList(futures),
Functions.constant(statement));
}
ResultSetFuture executeQuery(Message.Request msg, Statement statement) {
DefaultResultSetFuture future = new DefaultResultSetFuture(this, configuration().getProtocolOptions().getProtocolVersion(), msg);
execute(future, statement);
return future;
}
void cleanupIdleConnections(long now) {
for (HostConnectionPool pool : pools.values()) {
pool.cleanupIdleConnections(now);
}
}
private static class State implements Session.State {
private final SessionManager session;
private final List<Host> connectedHosts;
private final int[] openConnections;
private final int[] trashedConnections;
private final int[] inFlightQueries;
private State(SessionManager session) {
this.session = session;
this.connectedHosts = ImmutableList.copyOf(session.pools.keySet());
this.openConnections = new int[connectedHosts.size()];
this.trashedConnections = new int[connectedHosts.size()];
this.inFlightQueries = new int[connectedHosts.size()];
int i = 0;
for (Host h : connectedHosts) {
HostConnectionPool p = session.pools.get(h);
// It's possible we race and the host has been removed since the beginning of this
// functions. In that case, the fact it's part of getConnectedHosts() but has no opened
// connections will be slightly weird, but it's unlikely enough that we don't bother avoiding.
if (p == null) {
openConnections[i] = 0;
trashedConnections[i] = 0;
inFlightQueries[i] = 0;
continue;
}
openConnections[i] = p.opened();
inFlightQueries[i] = p.totalInFlight.get();
trashedConnections[i] = p.trashed();
i++;
}
}
private int getIdx(Host h) {
// We guarantee that we only ever create one Host object per-address, which means that '=='
// comparison is a proper way to test Host equality. Given that, the number of hosts
// per-session will always be small enough (even 1000 is kind of small and even with a 1000+
// node cluster, you probably don't want a Session to connect to all of them) that iterating
// over connectedHosts will never be much more inefficient than keeping a
// Map<Host, SomeStructureForHostInfo>. And it's less garbage/memory consumption so...
for (int i = 0; i < connectedHosts.size(); i++)
if (h == connectedHosts.get(i))
return i;
return -1;
}
@Override
public Session getSession() {
return session;
}
@Override
public Collection<Host> getConnectedHosts() {
return connectedHosts;
}
@Override
public int getOpenConnections(Host host) {
int i = getIdx(host);
return i < 0 ? 0 : openConnections[i];
}
@Override
public int getTrashedConnections(Host host) {
int i = getIdx(host);
return i < 0 ? 0 : trashedConnections[i];
}
@Override
public int getInFlightQueries(Host host) {
int i = getIdx(host);
return i < 0 ? 0 : inFlightQueries[i];
}
}
}