server/protocols/protocols-library/src/main/java/org/apache/james/protocols/lib/netty/AbstractServerFactory.java

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package org.apache.james.protocols.lib.netty;

import java.util.List;
import java.util.stream.Stream;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

import org.apache.commons.configuration2.HierarchicalConfiguration;
import org.apache.commons.configuration2.tree.ImmutableNode;
import org.apache.james.lifecycle.api.Configurable;

/**
 * Abstract base class for Factories that need to create {@link AbstractConfigurableAsyncServer}'s via configuration files
 */
public abstract class AbstractServerFactory implements Configurable, CertificateReloadable.Factory {

    private List<AbstractConfigurableAsyncServer> servers;
    private HierarchicalConfiguration<ImmutableNode> config;

    /**
     * Create {@link AbstractConfigurableAsyncServer} servers, inject dependencies and configure them before return all fo them in a {@link List}
     *
     * @return servers
     */
    protected abstract List<AbstractConfigurableAsyncServer> createServers(HierarchicalConfiguration<ImmutableNode> config) throws Exception;
    
    @Override
    public void configure(HierarchicalConfiguration<ImmutableNode> config) {
        this.config = config;
    }

    @PostConstruct
    public void init() throws Exception {
        servers = createServers(config);
        for (AbstractConfigurableAsyncServer server: servers) {
            server.init();
        }
    }
    
    /**
     * @return all {@link AbstractConfigurableAsyncServer} instances that was create via this Factory
     */
    public List<AbstractConfigurableAsyncServer> getServers() {
        return servers;
    }
    
    @PreDestroy
    public void destroy() {
        for (AbstractConfigurableAsyncServer server: servers) {
            server.destroy();
        }
    }

    @Override
    public Stream<AbstractConfigurableAsyncServer> certificatesReloadable() {
        return getServers().stream()
            .filter(AbstractConfigurableAsyncServer::isEnabled);
    }
}