SingletonPolicyBuilder.java example

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 * This software is distributed in the hope that it will be useful,
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 * Lesser General Public License for more details.
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package org.wildfly.extension.clustering.singleton;

import static org.wildfly.extension.clustering.singleton.SingletonPolicyResourceDefinition.Attribute.*;
import static org.wildfly.extension.clustering.singleton.SingletonPolicyResourceDefinition.Capability.*;

import java.util.stream.Stream;

import org.jboss.as.clustering.controller.CapabilityServiceNameProvider;
import org.jboss.as.clustering.controller.ResourceServiceBuilder;
import org.jboss.as.clustering.dmr.ModelNodes;
import org.jboss.as.controller.OperationContext;
import org.jboss.as.controller.OperationFailedException;
import org.jboss.as.controller.PathAddress;
import org.jboss.dmr.ModelNode;
import org.jboss.msc.service.Service;
import org.jboss.msc.service.ServiceBuilder;
import org.jboss.msc.service.ServiceController;
import org.jboss.msc.service.ServiceName;
import org.jboss.msc.service.ServiceTarget;
import org.jboss.msc.service.ValueService;
import org.jboss.msc.value.ImmediateValue;
import org.wildfly.clustering.service.Builder;
import org.wildfly.clustering.service.InjectedValueDependency;
import org.wildfly.clustering.service.ValueDependency;
import org.wildfly.clustering.singleton.SingletonElectionPolicy;
import org.wildfly.clustering.singleton.SingletonPolicy;
import org.wildfly.clustering.singleton.SingletonServiceBuilderFactory;
import org.wildfly.clustering.spi.ClusteringCacheRequirement;

/**
 * Builds a service that provides a {@link SingletonPolicy}.
 * @author Paul Ferraro
 */
public class SingletonPolicyBuilder extends CapabilityServiceNameProvider implements ResourceServiceBuilder<SingletonPolicy>, SingletonPolicy {

    private final ValueDependency<SingletonElectionPolicy> policy;

    private volatile ValueDependency<SingletonServiceBuilderFactory> factory;
    private volatile int quorum;

    public SingletonPolicyBuilder(PathAddress address) {
        super(POLICY, address);
        this.policy = new InjectedValueDependency<>(ElectionPolicyResourceDefinition.Capability.ELECTION_POLICY.getServiceName(address.append(ElectionPolicyResourceDefinition.WILDCARD_PATH)), SingletonElectionPolicy.class);
    }

    @Override
    public ServiceBuilder<SingletonPolicy> build(ServiceTarget target) {
        Service<SingletonPolicy> service = new ValueService<>(new ImmediateValue<>(this));
        ServiceBuilder<SingletonPolicy> builder = target.addService(this.getServiceName(), service).setInitialMode(ServiceController.Mode.PASSIVE);
        Stream.of(this.policy, this.factory).forEach(dependency -> dependency.register(builder));
        return builder;
    }

    @Override
    public Builder<SingletonPolicy> configure(OperationContext context, ModelNode model) throws OperationFailedException {
        String containerName = CACHE_CONTAINER.resolveModelAttribute(context, model).asString();
        String cacheName = ModelNodes.optionalString(CACHE.resolveModelAttribute(context, model)).orElse(null);
        this.factory = new InjectedValueDependency<>(ClusteringCacheRequirement.SINGLETON_SERVICE_BUILDER_FACTORY.getServiceName(context, containerName, cacheName), SingletonServiceBuilderFactory.class);
        this.quorum = QUORUM.resolveModelAttribute(context, model).asInt();
        return this;
    }

    @Override
    public <T> Builder<T> createSingletonServiceBuilder(ServiceName name, Service<T> service) {
        return this.factory.getValue().createSingletonServiceBuilder(name, service)
                .electionPolicy(this.policy.getValue())
                .requireQuorum(this.quorum)
                ;
    }

    @Override
    public <T> Builder<T> createSingletonServiceBuilder(ServiceName name, Service<T> primaryService, Service<T> backupService) {
        return this.factory.getValue().createSingletonServiceBuilder(name, primaryService, backupService)
                .electionPolicy(this.policy.getValue())
                .requireQuorum(this.quorum)
                ;
    }

    @Override
    public String toString() {
        return this.getServiceName().getSimpleName();
    }
}