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The official Couchbase JVM Core IO Library
/**
* Copyright (c) 2015 Couchbase, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALING
* IN THE SOFTWARE.
*/
package com.couchbase.client.core.service;
import com.couchbase.client.core.CouchbaseException;
import com.couchbase.client.core.ResponseEvent;
import com.couchbase.client.core.endpoint.Endpoint;
import com.couchbase.client.core.env.CoreEnvironment;
import com.couchbase.client.core.message.CouchbaseRequest;
import com.couchbase.client.core.message.internal.SignalFlush;
import com.couchbase.client.core.state.LifecycleState;
import com.couchbase.client.deps.com.lmax.disruptor.RingBuffer;
import rx.Subscriber;
import rx.functions.Action1;
import java.util.concurrent.atomic.AtomicReference;
/**
* This service lazily creates an Endpoint if needed and reuses it.
*
* If no storedEndpoint is currently found, a new one is created and stored - the request is dispatched to it. When
* subsequent requests come along they are dispatched to the same storedEndpoint. If the storedEndpoint dies for some reason
* it is cleaned up and a new one is created on the next attempt.
*
* @author Michael Nitschinger
* @since 1.1.2
*/
public abstract class AbstractLazyService extends AbstractDynamicService {
private final AtomicReference storedEndpoint = new AtomicReference();
public AbstractLazyService(String hostname, String bucket, String password, int port, CoreEnvironment env,
RingBuffer responseBuffer, EndpointFactory endpointFactory) {
super(hostname, bucket, password, port, env, 0, responseBuffer, endpointFactory);
}
@Override
protected void dispatch(final CouchbaseRequest request) {
if (storedEndpoint.get() == null) {
final Endpoint newEndpoint = createEndpoint();
if (storedEndpoint.compareAndSet(null, newEndpoint)) {
endpointStates().register(newEndpoint, newEndpoint);
newEndpoint
.connect()
.subscribe(new Subscriber() {
@Override
public void onCompleted() {
}
@Override
public void onError(Throwable e) {
request.observable().onError(e);
}
@Override
public void onNext(LifecycleState lifecycleState) {
if (lifecycleState == LifecycleState.DISCONNECTED) {
request.observable().onError(new CouchbaseException("Could not connect storedEndpoint."));
}
}
});
whenState(newEndpoint, LifecycleState.DISCONNECTED, new Action1() {
@Override
public void call(LifecycleState lifecycleState) {
endpointStates().deregister(newEndpoint);
storedEndpoint.set(null);
}
});
} else {
newEndpoint.disconnect();
}
}
sendAndFlushWhenConnected(storedEndpoint.get(), request);
}
/**
* Helper method to send the request and also a flush afterwards.
*
* @param endpoint the endpoint to send the reques to.
* @param request the reques to send.
*/
private static void sendAndFlushWhenConnected(final Endpoint endpoint, final CouchbaseRequest request) {
whenState(endpoint, LifecycleState.CONNECTED, new Action1() {
@Override
public void call(LifecycleState lifecycleState) {
endpoint.send(request);
endpoint.send(SignalFlush.INSTANCE);
}
});
}
/**
* Exposes the current endpoint to a subclass for proper testing.
*
* @return the endpoint or null if not set.
*/
Endpoint endpoint() {
return storedEndpoint.get();
}
}