java/dagger/spi/model/RequestKind.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.spi.model;

import static com.google.common.base.CaseFormat.UPPER_CAMEL;
import static com.google.common.base.CaseFormat.UPPER_UNDERSCORE;

import dagger.Lazy;
import dagger.producers.Produced;
import dagger.producers.Producer;
import javax.inject.Provider;

/**
 * Represents the different kinds of {@link javax.lang.model.type.TypeMirror types} that may be
 * requested as dependencies for the same key. For example, {@code String}, {@code
 * Provider<String>}, and {@code Lazy<String>} can all be requested if a key exists for {@code
 * String}; they have the {@link #INSTANCE}, {@link #PROVIDER}, and {@link #LAZY} request kinds,
 * respectively.
 */
public enum RequestKind {
  /** A default request for an instance. E.g.: {@code FooType} */
  INSTANCE,

  /** A request for a {@link Provider}. E.g.: {@code Provider<FooType>} */
  PROVIDER,

  /** A request for a {@link Lazy}. E.g.: {@code Lazy<FooType>} */
  LAZY,

  /** A request for a {@link Provider} of a {@link Lazy}. E.g.: {@code Provider<Lazy<FooType>>} */
  PROVIDER_OF_LAZY,

  /**
   * A request for a members injection. E.g. {@code void injectMembers(FooType);}. Can only be
   * requested by component interfaces.
   */
  MEMBERS_INJECTION,

  /** A request for a {@link Producer}. E.g.: {@code Producer<FooType>} */
  PRODUCER,

  /** A request for a {@link Produced}. E.g.: {@code Produced<FooType>} */
  PRODUCED,

  /**
   * A request for a {@link com.google.common.util.concurrent.ListenableFuture}. E.g.: {@code
   * ListenableFuture<FooType>}. These can only be requested by component interfaces.
   */
  FUTURE,
  ;

  /** Returns a string that represents requests of this kind for a key. */
  public String format(Key key) {
    switch (this) {
      case INSTANCE:
        return key.toString();

      case PROVIDER_OF_LAZY:
        return String.format("Provider<Lazy<%s>>", key);

      case MEMBERS_INJECTION:
        return String.format("injectMembers(%s)", key);

      case FUTURE:
        return String.format("ListenableFuture<%s>", key);

      default:
        return String.format("%s<%s>", UPPER_UNDERSCORE.to(UPPER_CAMEL, name()), key);
    }
  }
}