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/*
* Copyright (c) 2008-2020, Hazelcast, Inc. All Rights Reserved.
*
* 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.hazelcast.client;
import com.hazelcast.client.config.ClientConfig;
import com.hazelcast.client.config.ClientFailoverConfig;
import com.hazelcast.client.connection.AddressProvider;
import com.hazelcast.client.impl.clientside.ClientConnectionManagerFactory;
import com.hazelcast.client.impl.clientside.DefaultClientConnectionManagerFactory;
import com.hazelcast.client.impl.clientside.HazelcastClientInstanceImpl;
import com.hazelcast.client.impl.clientside.HazelcastClientProxy;
import com.hazelcast.config.InvalidConfigurationException;
import com.hazelcast.core.DuplicateInstanceNameException;
import com.hazelcast.core.HazelcastException;
import com.hazelcast.core.HazelcastInstance;
import com.hazelcast.core.OutOfMemoryHandler;
import com.hazelcast.instance.HazelcastInstanceFactory.InstanceFuture;
import com.hazelcast.instance.OutOfMemoryErrorDispatcher;
import com.hazelcast.util.EmptyStatement;
import com.hazelcast.util.ExceptionUtil;
import java.util.Collection;
import java.util.Collections;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicInteger;
import static com.hazelcast.client.impl.clientside.FailoverClientConfigSupport.resolveClientConfig;
import static com.hazelcast.client.impl.clientside.FailoverClientConfigSupport.resolveClientFailoverConfig;
import static com.hazelcast.util.Preconditions.checkHasText;
import static com.hazelcast.util.SetUtil.createHashSet;
/**
* The HazelcastClient is comparable to the {@link com.hazelcast.core.Hazelcast} class and provides the ability
* the create and manage Hazelcast clients. Hazelcast clients are {@link HazelcastInstance} implementations, so
* in most cases most of the code is unaware of talking to a cluster member or a client.
*
* Smart vs unisocket clients
* Hazelcast Client enables you to do all Hazelcast operations without being a member of the cluster. Clients can be:
*
* - smart: this means that they immediately can send an operation like map.get(key) to the member that owns that
* specific key.
*
* -
* unisocket: it will connect to a random member in the cluster and send requests to this member. This member then needs
* to send the request to the correct member.
*
*
* For more information see {@link com.hazelcast.client.config.ClientNetworkConfig#setSmartRouting(boolean)}.
*
* High availability
* When the connected cluster member dies, client will automatically switch to another live member.
*/
public final class HazelcastClient {
private static final AtomicInteger CLIENT_ID_GEN = new AtomicInteger();
private static final ConcurrentMap> CLIENTS
= new ConcurrentHashMap>(5);
static {
OutOfMemoryErrorDispatcher.setClientHandler(new ClientOutOfMemoryHandler());
}
private HazelcastClient() {
}
/**
* Creates a new HazelcastInstance (a new client in a cluster).
* This method allows you to create and run multiple instances
* of Hazelcast clients on the same JVM.
*
* To shutdown all running HazelcastInstances (all clients on this JVM)
* call {@link #shutdownAll()}.
*
* Hazelcast will look into two places for the configuration file:
*
* -
* System property: Hazelcast will first check if "hazelcast.client.config" system property is set to a file or a
* {@code classpath:...} path. The configuration can either be an XML or a YAML configuration, distinguished by the
* suffix ('.xml' or '.yaml') of the provided configuration file's name
* Examples: -Dhazelcast.client.config=C:/myhazelcastclient.xml ,
* -Dhazelcast.client.config=classpath:the-hazelcast-config.yaml ,
* -Dhazelcast.client.config=classpath:com/mydomain/hazelcast.xml
*
* -
* "hazelcast-client.xml" file in current working directory
*
* -
* Classpath: Hazelcast will check classpath for hazelcast-client.xml file.
*
* -
* "hazelcast-client.yaml" file in current working directory
*
* -
* Classpath: Hazelcast will check classpath for hazelcast-client.yaml file.
*
*
* If Hazelcast doesn't find any config file, it will start with the default configuration (hazelcast-client-default.xml)
* located in hazelcast.jar.
*
* @return the new HazelcastInstance
* @see #shutdownAll()
* @see #getHazelcastClientByName(String) (String)
*/
public static HazelcastInstance newHazelcastClient() {
return newHazelcastClientInternal(null, resolveClientConfig(null), null);
}
/**
* Creates a new HazelcastInstance (a new client in a cluster).
* This method allows you to create and run multiple instances
* of Hazelcast clients on the same JVM.
*
* To shutdown all running HazelcastInstances (all clients on this JVM)
* call {@link #shutdownAll()}.
*
* @param config Configuration for the new HazelcastInstance (member)
* @return the new HazelcastInstance
* @see #shutdownAll()
* @see #getHazelcastClientByName(String) (String)
*/
public static HazelcastInstance newHazelcastClient(ClientConfig config) {
return newHazelcastClientInternal(null, resolveClientConfig(config), null);
}
/**
* Creates a client with cluster switch capability. Client will try to connect to alternative clusters according to
* {@link ClientFailoverConfig} when it disconnects from a cluster.
*
* The configuration is loaded using using the following resolution mechanism:
*
* - first it checks if a system property 'hazelcast.client.failover.config' is set. If it exist and it begins with
* 'classpath:', then a classpath resource is loaded. Else it will assume it is a file reference. The configuration can
* either be an XML or a YAML configuration, distinguished by the suffix ('.xml' or '.yaml') of the provided configuration
* file's name
* - it checks if a hazelcast-client-failover.xml is available in the working dir
* - it checks if a hazelcast-client-failover.xml is available on the classpath
* - it checks if a hazelcast-client-failover.yaml is available in the working dir
* - it checks if a hazelcast-client-failover.yaml is available on the classpath
* - if none available {@link HazelcastException} is thrown
*
*
* @return the client instance
* @throws HazelcastException if no failover configuration is found
* @throws InvalidConfigurationException if the loaded failover configuration is not valid
*/
public static HazelcastInstance newHazelcastFailoverClient() {
return newHazelcastClientInternal(null, null, resolveClientFailoverConfig());
}
/**
* Creates a client with cluster switch capability. Client will try to connect to alternative clusters according to
* {@link ClientFailoverConfig} when it disconnects from a cluster.
*
* If provided clientFailoverConfig is {@code null}, the configuration is loaded using using the following resolution
* mechanism:
*
* - first it checks if a system property 'hazelcast.client.failover.config' is set. If it exist and it begins with
* 'classpath:', then a classpath resource is loaded. Else it will assume it is a file reference. The configuration
* can either be an XML or a YAML configuration, distinguished by the suffix ('.xml' or '.yaml') of the provided
* configuration file's name
* - it checks if a hazelcast-client-failover.xml is available in the working dir
* - it checks if a hazelcast-client-failover.xml is available on the classpath
* - it checks if a hazelcast-client-failover.yaml is available in the working dir
* - it checks if a hazelcast-client-failover.yaml is available on the classpath
* - if none available {@link HazelcastException} is thrown
*
*
* @param clientFailoverConfig config describing the failover configs and try count
* @return the client instance
* @throws HazelcastException if no failover configuration is found
* @throws InvalidConfigurationException if the provided or the loaded failover configuration is not valid
*/
public static HazelcastInstance newHazelcastFailoverClient(ClientFailoverConfig clientFailoverConfig) {
return newHazelcastClientInternal(null, null, resolveClientFailoverConfig(clientFailoverConfig));
}
/**
* Returns an existing HazelcastClient with instanceName.
*
* @param instanceName Name of the HazelcastInstance (client) which can be retrieved by {@link HazelcastInstance#getName()}
* @return HazelcastInstance
*/
public static HazelcastInstance getHazelcastClientByName(String instanceName) {
InstanceFuture future = CLIENTS.get(instanceName);
if (future == null) {
return null;
}
try {
return future.get();
} catch (IllegalStateException t) {
return null;
}
}
/**
* Gets or creates a new HazelcastInstance (a new client in a cluster) with the default XML configuration looked up in:
*
* -
* System property: Hazelcast will first check if "hazelcast.client.config" system property is set to a file or a
* {@code classpath:...} path. The configuration can either be an XML or a YAML configuration, distinguished by the
* suffix ('.xml' or '.yaml') of the provided configuration file's name
* Examples: -Dhazelcast.client.config=C:/myhazelcastclient.xml ,
* -Dhazelcast.client.config=classpath:the-hazelcast-config.yaml ,
* -Dhazelcast.client.config=classpath:com/mydomain/hazelcast.xml
*
* -
* "hazelcast-client.xml" file in current working directory
*
* -
* Classpath: Hazelcast will check classpath for hazelcast-client.xml file.
*
* -
* "hazelcast-client.yaml" file in current working directory
*
* -
* Classpath: Hazelcast will check classpath for hazelcast-client.yaml file.
*
*
*
* If a configuration file is not located, an {@link IllegalArgumentException} will be thrown.
*
* If a Hazelcast instance with the same name as the configuration exists, then it is returned, otherwise it is created.
*
* @return the new HazelcastInstance
* @throws IllegalArgumentException if the instance name of the config is null or empty or if no config file can be
* located.
* @see #getHazelcastClientByName(String) (String)
*/
public static HazelcastInstance getOrCreateHazelcastClient() {
return getOrCreateClientInternal(null);
}
/**
* Gets or creates a new HazelcastInstance (a new client in a cluster) with a certain name.
*
* If a Hazelcast instance with the same name as the configuration exists, then it is returned, otherwise it is created.
*
* If {@code config} is {@code null}, Hazelcast will look into two places for the configuration file:
*
* -
* System property: Hazelcast will first check if "hazelcast.client.config" system property is set to a file or a
* {@code classpath:...} path. The configuration can either be an XML or a YAML configuration, distinguished by the
* suffix ('.xml' or '.yaml') of the provided configuration file's name
* Examples: -Dhazelcast.client.config=C:/myhazelcastclient.xml ,
* -Dhazelcast.client.config=classpath:the-hazelcast-config.yaml ,
* -Dhazelcast.client.config=classpath:com/mydomain/hazelcast.xml
*
* -
* "hazelcast-client.xml" file in current working directory
*
* -
* Classpath: Hazelcast will check classpath for hazelcast-client.xml file.
*
* -
* "hazelcast-client.yaml" file in current working directory
*
* -
* Classpath: Hazelcast will check classpath for hazelcast-client.yaml file.
*
*
*
* If a configuration file is not located, an {@link IllegalArgumentException} will be thrown.
*
* @param config Client configuration
* @return the new HazelcastInstance
* @throws IllegalArgumentException if the instance name of the config is null or empty or if no config file can be
* located.
* @see #getHazelcastClientByName(String) (String)
*/
public static HazelcastInstance getOrCreateHazelcastClient(ClientConfig config) {
return getOrCreateClientInternal(config);
}
/**
* Gets an immutable collection of all client HazelcastInstances created in this JVM.
*
* In managed environments such as Java EE or OSGi Hazelcast can be loaded by multiple classloaders. Typically you will get
* at least one classloader per every application deployed. In these cases only the client HazelcastInstances created
* by the same application will be seen, and instances created by different applications are invisible.
*
* The returned collection is a snapshot of the client HazelcastInstances. So changes to the client HazelcastInstances
* will not be visible in this collection.
*
* @return the collection of client HazelcastInstances
*/
public static Collection getAllHazelcastClients() {
Set result = createHashSet(CLIENTS.size());
for (InstanceFuture f : CLIENTS.values()) {
result.add(f.get());
}
return Collections.unmodifiableCollection(result);
}
/**
* Shuts down all the client HazelcastInstance created in this JVM.
*
* To be more precise it shuts down the HazelcastInstances loaded using the same classloader this HazelcastClient has been
* loaded with.
*
* This method is mostly used for testing purposes.
*
* @see #getAllHazelcastClients()
*/
public static void shutdownAll() {
for (InstanceFuture future : CLIENTS.values()) {
try {
HazelcastClientProxy proxy = future.get();
HazelcastClientInstanceImpl client = proxy.client;
if (client == null) {
continue;
}
proxy.client = null;
client.shutdown();
} catch (Throwable ignored) {
EmptyStatement.ignore(ignored);
}
}
OutOfMemoryErrorDispatcher.clearClients();
CLIENTS.clear();
}
/**
* Shutdown the provided client and remove it from the managed list
*
* @param instance the hazelcast client instance
*/
public static void shutdown(HazelcastInstance instance) {
if (instance instanceof HazelcastClientProxy) {
final HazelcastClientProxy proxy = (HazelcastClientProxy) instance;
HazelcastClientInstanceImpl client = proxy.client;
if (client == null) {
return;
}
proxy.client = null;
CLIENTS.remove(client.getName());
try {
client.shutdown();
} catch (Throwable ignored) {
EmptyStatement.ignore(ignored);
} finally {
OutOfMemoryErrorDispatcher.deregisterClient(client);
}
}
}
/**
* Shutdown the provided client and remove it from the managed list
*
* @param instanceName the hazelcast client instance name
*/
public static void shutdown(String instanceName) {
InstanceFuture future = CLIENTS.remove(instanceName);
if (future == null || !future.isSet()) {
return;
}
HazelcastClientProxy proxy = future.get();
HazelcastClientInstanceImpl client = proxy.client;
if (client == null) {
return;
}
proxy.client = null;
try {
client.shutdown();
} catch (Throwable ignored) {
EmptyStatement.ignore(ignored);
} finally {
OutOfMemoryErrorDispatcher.deregisterClient(client);
}
}
/**
* Sets OutOfMemoryHandler to be used when an OutOfMemoryError
* is caught by Hazelcast Client threads.
*
*
* Warning: OutOfMemoryHandler may not be called although JVM throws
* OutOfMemoryError.
* Because error may be thrown from an external (user thread) thread
* and Hazelcast may not be informed about OutOfMemoryError.
*
*
* @param outOfMemoryHandler set when an OutOfMemoryError is caught by HazelcastClient threads
* @see OutOfMemoryError
* @see OutOfMemoryHandler
*/
public static void setOutOfMemoryHandler(OutOfMemoryHandler outOfMemoryHandler) {
OutOfMemoryErrorDispatcher.setClientHandler(outOfMemoryHandler);
}
static HazelcastInstance newHazelcastClientInternal(AddressProvider addressProvider, ClientConfig clientConfig,
ClientFailoverConfig failoverConfig) {
checkConfigs(clientConfig, failoverConfig);
String instanceName = getInstanceName(clientConfig, failoverConfig);
InstanceFuture future = new InstanceFuture();
if (CLIENTS.putIfAbsent(instanceName, future) != null) {
throw new DuplicateInstanceNameException("HazelcastClientInstance with name '" + instanceName
+ "' already exists!");
}
try {
return constructHazelcastClient(addressProvider, clientConfig, failoverConfig, instanceName, future);
} catch (Throwable t) {
CLIENTS.remove(instanceName, future);
future.setFailure(t);
throw ExceptionUtil.rethrow(t);
}
}
private static HazelcastInstance getOrCreateClientInternal(ClientConfig config) {
config = resolveClientConfig(config);
String instanceName = config.getInstanceName();
checkHasText(instanceName, "instanceName must contain text");
InstanceFuture future = CLIENTS.get(instanceName);
if (future != null) {
return future.get();
}
future = new InstanceFuture();
InstanceFuture found = CLIENTS.putIfAbsent(instanceName, future);
if (found != null) {
return found.get();
}
try {
return constructHazelcastClient(null, config, null, instanceName, future);
} catch (Throwable t) {
CLIENTS.remove(instanceName, future);
future.setFailure(t);
throw ExceptionUtil.rethrow(t);
}
}
private static HazelcastInstance constructHazelcastClient(AddressProvider addressProvider, ClientConfig clientConfig,
ClientFailoverConfig failoverConfig, String instanceName,
InstanceFuture future) {
final ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
HazelcastClientProxy proxy;
try {
Thread.currentThread().setContextClassLoader(HazelcastClient.class.getClassLoader());
ClientConnectionManagerFactory factory = new DefaultClientConnectionManagerFactory();
HazelcastClientInstanceImpl client = new HazelcastClientInstanceImpl(instanceName, clientConfig,
failoverConfig, factory, addressProvider);
client.start();
OutOfMemoryErrorDispatcher.registerClient(client);
proxy = new HazelcastClientProxy(client);
future.set(proxy);
} catch (Throwable t) {
throw ExceptionUtil.rethrow(t);
} finally {
Thread.currentThread().setContextClassLoader(contextClassLoader);
}
return proxy;
}
private static void checkConfigs(ClientConfig clientConfig, ClientFailoverConfig clientFailoverConfig) {
assert clientConfig != null || clientFailoverConfig != null : "At most one type of config can be provided";
assert clientConfig == null || clientFailoverConfig == null : "At least one config should be provided ";
}
static String getInstanceName(ClientConfig clientConfig, ClientFailoverConfig failoverConfig) {
int instanceNum = CLIENT_ID_GEN.incrementAndGet();
String instanceName;
if (clientConfig != null) {
instanceName = clientConfig.getInstanceName();
} else {
instanceName = failoverConfig.getClientConfigs().get(0).getInstanceName();
}
if (instanceName == null || instanceName.trim().length() == 0) {
instanceName = "hz.client_" + instanceNum;
}
return instanceName;
}
}