Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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 org.apache.omid; import com.google.common.base.Preconditions; import com.google.common.io.Resources; import org.apache.commons.beanutils.BeanUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.yaml.snakeyaml.Yaml; import java.io.IOException; import java.lang.reflect.InvocationTargetException; import java.nio.charset.Charset; import java.util.HashMap; import java.util.Map; public class YAMLUtils { private static final Logger LOG = LoggerFactory.getLogger(YAMLUtils.class); public void loadSettings(String resourcePath, String defaultResourcePath, Object bean) { try { Map properties = loadSettings(resourcePath, defaultResourcePath); BeanUtils.populate(bean, properties); } catch (IllegalAccessException | InvocationTargetException | IOException e) { throw new IllegalStateException(e); } } public void loadSettings(String resourcePath, Object bean) { try { Map properties = loadSettings(null, resourcePath); BeanUtils.populate(bean, properties); } catch (IllegalAccessException | InvocationTargetException | IOException e) { throw new IllegalStateException(e); } } @SuppressWarnings("unchecked") private Map loadSettings(String resourcePath, String defaultResourcePath) throws IOException { Map defaultSetting = loadAsMap(defaultResourcePath); Preconditions.checkState(defaultSetting.size() > 0, String.format("Failed to load file '%s' from classpath", defaultResourcePath)); if (resourcePath != null) { Map userSetting = loadAsMap(resourcePath); defaultSetting.putAll(userSetting); } return defaultSetting; } @SuppressWarnings("unchecked") private Map loadAsMap(String path) throws IOException { try { String content = Resources.toString(Resources.getResource(path), Charset.forName("UTF-8")); LOG.debug("Loaded resource file '{}'\n{}", path, content); Map settings = new Yaml().loadAs(content, Map.class); if (settings == null) { settings = new HashMap(0); } return settings; } catch (IllegalArgumentException e) { return new HashMap(); } } }