org.apache.hadoop.hive.common.cli.HiveFileProcessor.java Source code

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Here is the source code for org.apache.hadoop.hive.common.cli.HiveFileProcessor.java

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/**
 * 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.hadoop.hive.common.cli;

import java.io.BufferedReader;
import java.io.IOException;

import org.apache.commons.lang.StringUtils;
import org.apache.hadoop.io.IOUtils;

/**
 * HiveFileProcessor is used for processing a file consist of Hive executable
 * statements
 */
public abstract class HiveFileProcessor implements IHiveFileProcessor {

    public int processFile(String fileName) throws IOException {
        BufferedReader bufferedReader = null;
        try {
            bufferedReader = loadFile(fileName);
            return (processReader(bufferedReader));
        } finally {
            IOUtils.closeStream(bufferedReader);
        }
    }

    /**
     * load commands into buffered reader from the file
     * @param fileName
     * @return
     * @throws IOException
     */
    protected abstract BufferedReader loadFile(String fileName) throws IOException;

    /**
     * execute the buffered reader which stores the commands
     * @param reader the buffered reader
     * @return the return code of the execution result
     * @throws IOException
     */
    protected int processReader(BufferedReader reader) throws IOException {
        String line;
        StringBuilder qsb = new StringBuilder();
        while ((line = reader.readLine()) != null) {
            if (!line.startsWith("--")) {
                qsb.append(line);
            }
        }
        return processLine(qsb.toString());
    }

    /**
     * process the Hive command by lines
     * @param line contains a legal Hive command
     * @return the return code of the execution result
     */
    protected int processLine(String line) {
        int lastRet = 0, ret = 0;
        String command = "";
        for (String oneCmd : line.split(";")) {
            if (StringUtils.indexOf(oneCmd, "\\") != -1) {
                command += StringUtils.join(oneCmd.split("\\\\"));
            } else {
                command += oneCmd;
            }
            if (StringUtils.isBlank(command)) {
                continue;
            }

            ret = processCmd(command);
            command = "";
            lastRet = ret;
            if (ret != 0) {
                return ret;
            }
        }
        return lastRet;
    }

    /**
     * define the processor for each Hive command supported by Hive
     * @param cmd
     * @return the return code of the execution result
     */
    protected abstract int processCmd(String cmd);
}