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.kylin.common.persistence; import org.apache.commons.io.IOUtils; import java.io.InputStream; import java.util.HashMap; import java.util.Locale; import java.util.Map; import java.util.Properties; public class JDBCSqlQueryFormatProvider { static Map<String, Properties> cache = new HashMap<>(); public static JDBCSqlQueryFormat createJDBCSqlQueriesFormat(String dialect) { String key = String.format(Locale.ROOT, "/metadata-jdbc-%s.properties", dialect.toLowerCase(Locale.ROOT)); if (cache.containsKey(key)) { return new JDBCSqlQueryFormat(cache.get(key)); } else { Properties props = new Properties(); InputStream input = null; try { input = props.getClass().getResourceAsStream(key); props.load(input); if (!props.isEmpty()) { cache.put(key, props); } return new JDBCSqlQueryFormat(props); } catch (Exception e) { throw new RuntimeException( String.format(Locale.ROOT, "Can't find properties named %s for metastore", key), e); } finally { IOUtils.closeQuietly(input); } } } }