content: /*
   * 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 com.datastax.oss.driver.internal.core.config.composite;
  
  import com.datastax.oss.driver.api.core.config.DriverConfig;
  import com.datastax.oss.driver.api.core.config.DriverConfigLoader;
  import com.datastax.oss.driver.api.core.context.DriverContext;
  import com.datastax.oss.driver.internal.core.util.concurrent.CompletableFutures;
  import edu.umd.cs.findbugs.annotations.NonNull;
  import java.util.Objects;
  import java.util.concurrent.CompletableFuture;
  import java.util.concurrent.CompletionStage;
  
  public class CompositeDriverConfigLoader implements DriverConfigLoader {
  
    private final DriverConfigLoader primaryConfigLoader;
    private final DriverConfigLoader fallbackConfigLoader;
  
    public CompositeDriverConfigLoader(
        @NonNull DriverConfigLoader primaryConfigLoader,
        @NonNull DriverConfigLoader fallbackConfigLoader) {
      this.primaryConfigLoader = Objects.requireNonNull(primaryConfigLoader);
      this.fallbackConfigLoader = Objects.requireNonNull(fallbackConfigLoader);
    }
  
    @NonNull
    @Override
    public DriverConfig getInitialConfig() {
      DriverConfig primaryConfig = primaryConfigLoader.getInitialConfig();
      DriverConfig fallbackConfig = fallbackConfigLoader.getInitialConfig();
      return new CompositeDriverConfig(primaryConfig, fallbackConfig);
    }
  
    @Override
    public void onDriverInit(@NonNull DriverContext context) {
      fallbackConfigLoader.onDriverInit(context);
      primaryConfigLoader.onDriverInit(context);
    }
  
    @NonNull
    @Override
    public CompletionStage<Boolean> reload() {
      if (!primaryConfigLoader.supportsReloading() && !fallbackConfigLoader.supportsReloading()) {
        return CompletableFutures.failedFuture(
            new UnsupportedOperationException(
                "Reloading is not supported (this is a composite config, "
                    + "and neither the primary nor the fallback are reloadable)"));
      } else if (!primaryConfigLoader.supportsReloading()) {
        return fallbackConfigLoader.reload();
      } else if (!fallbackConfigLoader.supportsReloading()) {
        return primaryConfigLoader.reload();
      } else {
        CompletionStage<Boolean> primaryFuture = primaryConfigLoader.reload();
        CompletionStage<Boolean> fallbackFuture = fallbackConfigLoader.reload();
        CompletableFuture<Boolean> compositeFuture = new CompletableFuture<>();
        primaryFuture.whenComplete(
            (primaryChanged, primaryError) ->
                fallbackFuture.whenComplete(
                    (fallbackChanged, fallbackError) -> {
                      if (primaryError == null && fallbackError == null) {
                        compositeFuture.complete(primaryChanged || fallbackChanged);
                      } else if (fallbackError == null) {
                        compositeFuture.completeExceptionally(primaryError);
                      } else if (primaryError == null) {
                        compositeFuture.completeExceptionally(fallbackError);
                      } else {
                        primaryError.addSuppressed(fallbackError);
                        compositeFuture.completeExceptionally(primaryError);
                      }
                    }));
        return compositeFuture;
      }
    }
  
    @Override
    public boolean supportsReloading() {
      return primaryConfigLoader.supportsReloading() || fallbackConfigLoader.supportsReloading();
    }
  
    @Override
    public void close() {
      primaryConfigLoader.close();
      fallbackConfigLoader.close();
    }
  }
  