content: /*
   * Copyright (C) 2020 ActiveJ LLC.
   *
   * 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 io.activej.promise;
  
  import io.activej.async.callback.Callback;
  import org.jetbrains.annotations.Nullable;
  
  public interface SettableCallback<T> extends Callback<T> {
  	default void set(T result, @Nullable Exception e) {
  		accept(result, e);
  	}
  
  	default void set(T result) {
  		set(result, null);
  	}
  
  	default void setException(Exception e) {
  		set(null, e);
  	}
  
  	default boolean trySet(T result, @Nullable Exception e) {
  		if (isComplete()) return false;
  		set(result, e);
  		return true;
  	}
  
  	default boolean trySet(T result) {
  		return trySet(result, null);
  	}
  
  	default boolean trySetException(Exception e) {
  		return trySet(null, e);
  	}
  
  	boolean isComplete();
  
  	@Override
  	default void accept(T result, @Nullable Exception e) {
  		set(result, e);
  	}
  }
  