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.docs.context;
018
019import java.io.IOException;
020
021import org.springframework.boot.SpringApplication;
022import org.springframework.boot.env.EnvironmentPostProcessor;
023import org.springframework.boot.env.YamlPropertySourceLoader;
024import org.springframework.core.env.ConfigurableEnvironment;
025import org.springframework.core.env.PropertySource;
026import org.springframework.core.io.ClassPathResource;
027import org.springframework.core.io.Resource;
028
029/**
030 * An {@link EnvironmentPostProcessor} example that loads a YAML file.
031 *
032 * @author Stephane Nicoll
033 */
034// tag::example[]
035public class EnvironmentPostProcessorExample implements EnvironmentPostProcessor {
036
037        private final YamlPropertySourceLoader loader = new YamlPropertySourceLoader();
038
039        @Override
040        public void postProcessEnvironment(ConfigurableEnvironment environment,
041                        SpringApplication application) {
042                Resource path = new ClassPathResource("com/example/myapp/config.yml");
043                PropertySource<?> propertySource = loadYaml(path);
044                environment.getPropertySources().addLast(propertySource);
045        }
046
047        private PropertySource<?> loadYaml(Resource path) {
048                if (!path.exists()) {
049                        throw new IllegalArgumentException("Resource " + path + " does not exist");
050                }
051                try {
052                        return this.loader.load("custom-resource", path).get(0);
053                }
054                catch (IOException ex) {
055                        throw new IllegalStateException(
056                                        "Failed to load yaml configuration from " + path, ex);
057                }
058        }
059
060}
061// end::example[]