001/* 002 * Copyright 2012-2018 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.boot.origin; 018 019/** 020 * An interface that may be implemented by an object that can lookup {@link Origin} 021 * information from a given key. Can be used to add origin support to existing classes. 022 * 023 * @param <K> the lookup key type 024 * @author Phillip Webb 025 * @since 2.0.0 026 */ 027@FunctionalInterface 028public interface OriginLookup<K> { 029 030 /** 031 * Return the origin of the given key or {@code null} if the origin cannot be 032 * determined. 033 * @param key the key to lookup 034 * @return the origin of the key or {@code null} 035 */ 036 Origin getOrigin(K key); 037 038 /** 039 * Attempt to lookup the origin from the given source. If the source is not a 040 * {@link OriginLookup} or if an exception occurs during lookup then {@code null} is 041 * returned. 042 * @param source the source object 043 * @param key the key to lookup 044 * @param <K> the key type 045 * @return an {@link Origin} or {@code null} 046 */ 047 @SuppressWarnings("unchecked") 048 static <K> Origin getOrigin(Object source, K key) { 049 if (!(source instanceof OriginLookup)) { 050 return null; 051 } 052 try { 053 return ((OriginLookup<K>) source).getOrigin(key); 054 } 055 catch (Throwable ex) { 056 return null; 057 } 058 } 059 060}