sdks/java/testing/tpcds/src/main/java/org/apache/beam/sdk/tpcds/QueryReader.java

/*
 * 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.beam.sdk.tpcds;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.util.Objects;

/**
 * The QueryReader reads query file (the file's extension is '.sql' and content doesn't end with a ';'), write the query as a string and return it.
 */
public class QueryReader {
    /**
     * Reads a query file (.sql), return the query as a string.
     * @param queryFileName The name of the query file (such as "query1, query5...") which is stored in resource/queries directory
     * @return The query string stored in this file.
     * @throws Exception
     */
    public static String readQuery(String queryFileName) throws Exception {
        // Prepare the file reader.
        String queryFilePath = Objects.requireNonNull(QueryReader.class.getClassLoader().getResource("queries/" + queryFileName + ".sql")).getPath();
        File queryFile = new File(queryFilePath);
        FileReader fileReader = new FileReader(queryFile);
        BufferedReader reader = new BufferedReader(fileReader);

        // Read the file into stringBuilder.
        StringBuilder stringBuilder = new StringBuilder();
        String line;
        String ls = System.getProperty("line.separator");
        while ((line = reader.readLine()) != null) {
            stringBuilder.append(line);
            stringBuilder.append(ls);
        }

        // Delete the last new line separator.
        stringBuilder.deleteCharAt(stringBuilder.length() - 1);
        reader.close();

        String queryString = stringBuilder.toString();

        return queryString;
    }
}