java/dagger/internal/codegen/ServiceLoaders.java

/*
 * Copyright (C) 2021 The Dagger Authors.
 *
 * Licensed 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 dagger.internal.codegen;

import static com.google.common.base.Preconditions.checkState;

import androidx.room.compiler.processing.XProcessingEnv;
import com.google.common.collect.ImmutableSet;
import java.util.ServiceLoader;

/** A class that loads services for the {@link ComponentProcessor}. */
final class ServiceLoaders {

  private ServiceLoaders() {}

  /**
   * Returns the loaded services for the given class.
   *
   * <p>Note: This should only be called in Javac. This method will throw if called in KSP.
   */
  static <T> ImmutableSet<T> loadServices(XProcessingEnv processingEnv, Class<T> clazz) {
    checkState(
        processingEnv.getBackend() == XProcessingEnv.Backend.JAVAC,
        "Cannot load services for non-javac backend.");
    return ImmutableSet.copyOf(ServiceLoader.load(clazz, classloaderFor(processingEnv, clazz)));
  }

  private static ClassLoader classloaderFor(XProcessingEnv processingEnv, Class<?> clazz) {
    return clazz.getClassLoader();
  }
}