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The Core Camel Java DSL based router
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.apache.camel.cluster;
import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.Optional;
import org.apache.camel.CamelContextAware;
import org.apache.camel.Ordered;
import org.apache.camel.Service;
import org.apache.camel.spi.IdAware;
public interface CamelClusterService extends Service, CamelContextAware, IdAware, Ordered {
@Override
default int getOrder() {
return Ordered.LOWEST;
}
/**
* Get a view of the cluster bound to a namespace creating it if needed. Multiple
* calls to this method with the same namespace should return the same instance.
* The instance is automatically started the first time it is instantiated and
* if the cluster service is ready.
*
* @param namespace the namespace the view refer to.
* @return the view.
* @throws Exception if the view can't be created.
*/
CamelClusterView getView(String namespace) throws Exception;
/**
* Release a view if it has no references.
*
* @param view the view.
* @throws Exception
*/
void releaseView(CamelClusterView view) throws Exception;
/**
* Return the namespaces handled by this service.
*/
Collection getNamespaces();
/**
* Force start of the view associated to the give namespace.
*/
void startView(String namespace) throws Exception;
/**
* Force stop of the view associated to the give namespace.
*/
void stopView(String namespace) throws Exception;
/**
* Check if the service is the leader on the given namespace.
*
* @param namespace the namespace.
* @return
*/
boolean isLeader(String namespace);
/**
* Attributes associated to the service.
*/
default Map getAttributes() {
return Collections.emptyMap();
}
/**
* Access the underlying concrete CamelClusterService implementation to
* provide access to further features.
*
* @param clazz the proprietary class or interface of the underlying concrete CamelClusterService.
* @return an instance of the underlying concrete CamelClusterService as the required type.
*/
default T unwrap(Class clazz) {
if (CamelClusterService.class.isAssignableFrom(clazz)) {
return clazz.cast(this);
}
throw new IllegalArgumentException(
"Unable to unwrap this CamelClusterService type (" + getClass() + ") to the required type (" + clazz + ")"
);
}
@FunctionalInterface
interface Selector {
/**
* Select a specific CamelClusterService instance among a collection.
*/
Optional select(Collection services);
}
}