001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.juneau.commons.settings;
018
019/**
020 * Provider SPI for augmenting {@link Settings} with additional property sources.
021 */
022public interface PropertySourceProvider {
023
024   /**
025    * Creates a property source.
026    *
027    * @return The property source, or <jk>null</jk> to skip registration.
028    */
029   PropertySource create();
030
031   /**
032    * Sort key used by ServiceLoader wiring.
033    *
034    * <p>
035    * Lower values are added first.
036    *
037    * @return The order value.
038    */
039   default int order() {
040      return 0;
041   }
042}