code: /*
   * Copyright (c) 2019 the Eclipse Milo Authors
   *
   * This program and the accompanying materials are made
   * available under the terms of the Eclipse Public License 2.0
   * which is available at https://www.eclipse.org/legal/epl-2.0/
   *
   * SPDX-License-Identifier: EPL-2.0
   */
  
  package org.eclipse.milo.opcua.stack.client;
  
  import java.security.KeyPair;
  import java.security.cert.X509Certificate;
  import java.util.Optional;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.ScheduledExecutorService;
  import java.util.function.Consumer;
  
  import io.netty.channel.nio.NioEventLoopGroup;
  import io.netty.util.HashedWheelTimer;
  import org.eclipse.milo.opcua.stack.client.security.ClientCertificateValidator;
  import org.eclipse.milo.opcua.stack.core.channel.EncodingLimits;
  import org.eclipse.milo.opcua.stack.core.types.builtin.unsigned.UInteger;
  import org.eclipse.milo.opcua.stack.core.types.structured.EndpointDescription;
  
  public interface UaStackClientConfig {
  
      /**
       * Get the endpoint to connect to.
       *
       * @return the {@link EndpointDescription} to connect to.
       */
      EndpointDescription getEndpoint();
  
      /**
       * Get the {@link KeyPair} to use.
       * <p>
       * May be absent if connecting without security, must be present if connecting with security.
       *
       * @return an {@link Optional} containing the {@link KeyPair} to use.
       */
      Optional<KeyPair> getKeyPair();
  
      /**
       * Get the {@link X509Certificate} to use.
       * <p>
       * May be absent if connecting without security, must be present if connecting with security.
       *
       * @return an {@link Optional} containing the {@link X509Certificate} to use.
       */
      Optional<X509Certificate> getCertificate();
  
      /**
       * Get the {@link X509Certificate} to use as well as any certificates in the certificate chain.
       *
       * @return the {@link X509Certificate} to use as well as any certificates in the certificate chain.
       */
      Optional<X509Certificate[]> getCertificateChain();
  
      /**
       * Get the {@link ClientCertificateValidator} this client will use to validate server certificates when connecting.
       *
       * @return the validator this client will use to validate server certificates when connecting.
       */
      ClientCertificateValidator getCertificateValidator();
  
      /**
       * @return the configured {@link EncodingLimits}.
       */
      EncodingLimits getEncodingLimits();
  
      /**
       * @return the {@link ExecutorService} used by the client.
       */
      ExecutorService getExecutor();
  
      /**
       * @return the {@link ScheduledExecutorService} used by the client.
       */
      ScheduledExecutorService getScheduledExecutor();
  
      /**
       * @return the {@link NioEventLoopGroup} used by the client.
       */
      NioEventLoopGroup getEventLoop();
  
      /**
       * @return the {@link HashedWheelTimer} used by the client.
       */
      HashedWheelTimer getWheelTimer();
  
      /**
       * @return the timeout, in milliseconds, when opening a socket connection to a remote host.
       */
      UInteger getConnectTimeout();
  
      /**
       * @return the timeout, in milliseconds, to wait for an Acknowledge message in response to the client's
       * Hello message.
       */
      UInteger getAcknowledgeTimeout();
  
      /**
       * @return the timeout, in milliseconds, before failing a request due to timeout.
       */
      UInteger getRequestTimeout();
  
      /**
       * @return the secure channel lifetime to request, in milliseconds.
       */
      UInteger getChannelLifetime();
  
      static UaStackClientConfigBuilder builder() {
          return new UaStackClientConfigBuilder();
      }
  
      /**
       * Copy the values from an existing {@link UaStackClientConfig} into a new {@link UaStackClientConfigBuilder}.
       * This builder can be used to make any desired modifications before invoking
       * {@link UaStackClientConfigBuilder#build()} to produce a new config.
       *
       * @param config the {@link UaStackClientConfig} to copy from.
       * @return a {@link UaStackClientConfigBuilder} pre-populated with values from {@code config}.
       */
      static UaStackClientConfigBuilder copy(UaStackClientConfig config) {
          UaStackClientConfigBuilder builder = new UaStackClientConfigBuilder();
  
          builder.setEndpoint(config.getEndpoint());
          config.getKeyPair().ifPresent(builder::setKeyPair);
          config.getCertificate().ifPresent(builder::setCertificate);
          config.getCertificateChain().ifPresent(builder::setCertificateChain);
          builder.setCertificateValidator(config.getCertificateValidator());
          builder.setEncodingLimits(config.getEncodingLimits());
          builder.setChannelLifetime(config.getChannelLifetime());
          builder.setExecutor(config.getExecutor());
          builder.setScheduledExecutor(config.getScheduledExecutor());
          builder.setEventLoop(config.getEventLoop());
          builder.setWheelTimer(config.getWheelTimer());
          builder.setConnectTimeout(config.getConnectTimeout());
          builder.setAcknowledgeTimeout(config.getAcknowledgeTimeout());
          builder.setRequestTimeout(config.getRequestTimeout());
  
          return builder;
      }
  
      /**
       * Copy the values from an existing {@link UaStackClientConfig} into a new {@link UaStackClientConfigBuilder}
       * and then submit the builder to the provided consumer for modification.
       *
       * @param config   the {@link UaStackClientConfig} to copy from.
       * @param consumer a {@link Consumer} that may modify the builder.
       * @return a {@link UaStackClientConfig} built from the builder provided to {@code consumer}.
       */
      static UaStackClientConfig copy(
          UaStackClientConfig config,
          Consumer<UaStackClientConfigBuilder> consumer) {
  
          UaStackClientConfigBuilder builder = copy(config);
  
          consumer.accept(builder);
  
          return builder.build();
      }
  
  }
  