Java tutorial
/* * Copyright (c) 2015 Spotify AB. * * 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 com.spotify.heroic.metric.datastax.schema; import com.datastax.driver.core.PreparedStatement; import com.datastax.driver.core.Session; import com.google.common.base.Charsets; import com.google.common.io.CharStreams; import com.spotify.heroic.metric.datastax.Async; import com.spotify.heroic.metric.datastax.ManagedSetupConnection; import eu.toolchain.async.AsyncFramework; import eu.toolchain.async.AsyncFuture; import lombok.RequiredArgsConstructor; import org.apache.commons.lang3.text.StrSubstitutor; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.util.Map; @RequiredArgsConstructor public class AbstractCassandraSchema { protected final AsyncFramework async; protected AsyncFuture<PreparedStatement> prepareTemplate(final Map<String, String> values, Session s, final String path) throws IOException { return Async.bind(async, s.prepareAsync(loadTemplate(path, values))); } protected AsyncFuture<PreparedStatement> prepareAsync(final Map<String, String> values, Session s, final String cql) { return Async.bind(async, s.prepareAsync(variables(cql, values))); } private String loadTemplate(final String path, final Map<String, String> values) throws IOException { final String string; final ClassLoader loader = ManagedSetupConnection.class.getClassLoader(); try (final InputStream is = loader.getResourceAsStream(path)) { if (is == null) { throw new IOException("No such resource: " + path); } string = CharStreams.toString(new InputStreamReader(is, Charsets.UTF_8)); } return new StrSubstitutor(values, "{{", "}}").replace(string); } private String variables(String cql, Map<String, String> values) { return new StrSubstitutor(values, "{{", "}}").replace(cql); } }