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* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you 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.elasticsearch.transport;
import org.elasticsearch.Version;
import org.elasticsearch.action.ActionListener;
import org.elasticsearch.cluster.node.DiscoveryNode;
import org.elasticsearch.common.component.LifecycleComponent;
import org.elasticsearch.common.transport.BoundTransportAddress;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.common.util.concurrent.ConcurrentCollections;
import org.elasticsearch.common.util.concurrent.ConcurrentMapLong;
import java.io.Closeable;
import java.io.IOException;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.Predicate;
public interface Transport extends LifecycleComponent {
/**
* Registers a new request handler
*/
void registerRequestHandler(RequestHandlerRegistry reg);
/**
* Returns the registered request handler registry for the given action or null if it's not registered
* @param action the action to look up
*/
RequestHandlerRegistry getRequestHandler(String action);
void setMessageListener(TransportMessageListener listener);
/**
* The address the transport is bound on.
*/
BoundTransportAddress boundAddress();
/**
* Further profile bound addresses
* @return null iff profiles are unsupported, otherwise a map with name of profile and its bound transport address
*/
Map profileBoundAddresses();
/**
* Returns an address from its string representation.
*/
TransportAddress[] addressesFromString(String address) throws UnknownHostException;
/**
* Returns a list of all local addresses for this transport
*/
List getDefaultSeedAddresses();
/**
* Opens a new connection to the given node. When the connection is fully connected, the listener is called.
* The ActionListener will be called on the calling thread or the generic thread pool.
*/
void openConnection(DiscoveryNode node, ConnectionProfile profile, ActionListener listener);
TransportStats getStats();
ResponseHandlers getResponseHandlers();
/**
* A unidirectional connection to a {@link DiscoveryNode}
*/
interface Connection extends Closeable {
/**
* The node this connection is associated with
*/
DiscoveryNode getNode();
/**
* Sends the request to the node this connection is associated with
* @param requestId see {@link ResponseHandlers#add(ResponseContext)} for details
* @param action the action to execute
* @param request the request to send
* @param options request options to apply
* @throws NodeNotConnectedException if the given node is not connected
*/
void sendRequest(long requestId, String action, TransportRequest request, TransportRequestOptions options) throws
IOException, TransportException;
/**
* The listener's {@link ActionListener#onResponse(Object)} method will be called when this
* connection is closed. No implementations currently throw an exception during close, so
* {@link ActionListener#onFailure(Exception)} will not be called.
*
* @param listener to be called
*/
void addCloseListener(ActionListener listener);
boolean isClosed();
/**
* Returns the version of the node this connection was established with.
*/
default Version getVersion() {
return getNode().getVersion();
}
/**
* Returns a key that this connection can be cached on. Delegating subclasses must delegate method call to
* the original connection.
*/
default Object getCacheKey() {
return this;
}
@Override
void close();
}
/**
* This class represents a response context that encapsulates the actual response handler, the action and the connection it was
* executed on.
*/
final class ResponseContext {
private final TransportResponseHandler handler;
private final Connection connection;
private final String action;
ResponseContext(TransportResponseHandler handler, Connection connection, String action) {
this.handler = handler;
this.connection = connection;
this.action = action;
}
public TransportResponseHandler handler() {
return handler;
}
public Connection connection() {
return this.connection;
}
public String action() {
return this.action;
}
}
/**
* This class is a registry that allows
*/
final class ResponseHandlers {
private final ConcurrentMapLong> handlers = ConcurrentCollections
.newConcurrentMapLongWithAggressiveConcurrency();
private final AtomicLong requestIdGenerator = new AtomicLong();
/**
* Returns true if the give request ID has a context associated with it.
*/
public boolean contains(long requestId) {
return handlers.containsKey(requestId);
}
/**
* Removes and return the {@link ResponseContext} for the given request ID or returns
* null if no context is associated with this request ID.
*/
public ResponseContext remove(long requestId) {
return handlers.remove(requestId);
}
/**
* Adds a new response context and associates it with a new request ID.
* @return the new request ID
* @see Connection#sendRequest(long, String, TransportRequest, TransportRequestOptions)
*/
public long add(ResponseContext holder) {
long requestId = newRequestId();
ResponseContext existing = handlers.put(requestId, holder);
assert existing == null : "request ID already in use: " + requestId;
return requestId;
}
/**
* Returns a new request ID to use when sending a message via {@link Connection#sendRequest(long, String,
* TransportRequest, TransportRequestOptions)}
*/
long newRequestId() {
return requestIdGenerator.incrementAndGet();
}
/**
* Removes and returns all {@link ResponseContext} instances that match the predicate
*/
public List> prune(Predicate predicate) {
final List> holders = new ArrayList<>();
for (Map.Entry> entry : handlers.entrySet()) {
ResponseContext holder = entry.getValue();
if (predicate.test(holder)) {
ResponseContext remove = handlers.remove(entry.getKey());
if (remove != null) {
holders.add(holder);
}
}
}
return holders;
}
/**
* called by the {@link Transport} implementation when a response or an exception has been received for a previously
* sent request (before any processing or deserialization was done). Returns the appropriate response handler or null if not
* found.
*/
public TransportResponseHandler onResponseReceived(final long requestId,
final TransportMessageListener listener) {
ResponseContext context = handlers.remove(requestId);
listener.onResponseReceived(requestId, context);
if (context == null) {
return null;
} else {
return context.handler();
}
}
}
}