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.inject;
  
  import io.activej.inject.module.UniqueQualifierImpl;
  import org.jetbrains.annotations.Nullable;
  
  /**
   * This class holds utility methods used for validating and creating objects used as qualifiers.
   * Qualifiers serve as additional tags to distinguish different {@link Key keys} that have the same type.
   * <p>
   */
  public final class Qualifiers {
  
  	public static Object uniqueQualifier() {
  		return new UniqueQualifierImpl();
  	}
  
  	public static Object uniqueQualifier(@Nullable Object qualifier) {
  		return qualifier instanceof UniqueQualifierImpl ? qualifier : new UniqueQualifierImpl(qualifier);
  	}
  
  	public static boolean isUnique(@Nullable Object qualifier) {
  		return qualifier instanceof UniqueQualifierImpl;
  	}
  
  }
  