/*
 * 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.huawei.bigdata.spark.examples.hbasecontext;

import com.huawei.hadoop.security.LoginUtil;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.spark.JavaHBaseContext;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.spark.SparkConf;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.api.java.function.Function;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * This is a simple example of getting records in HBase
 * with the bulkGet function.
 */
public final class JavaHBaseBulkGetExample {
    private JavaHBaseBulkGetExample() {}

    public static void main(String[] args) throws IOException {
        if (args.length < 1) {
            System.out.println("JavaHBaseBulkGetExample  {tableName}");
            return;
        }
        LoginUtil.loginWithUserKeytab();
        String tableName = args[0];

        SparkConf sparkConf = new SparkConf().setAppName("JavaHBaseBulkGetExample " + tableName);
        JavaSparkContext jsc = new JavaSparkContext(sparkConf);

        try {
            List<byte[]> list = new ArrayList<byte[]>(5);
            list.add(Bytes.toBytes("1"));
            list.add(Bytes.toBytes("2"));
            list.add(Bytes.toBytes("3"));
            list.add(Bytes.toBytes("4"));
            list.add(Bytes.toBytes("5"));

            JavaRDD<byte[]> rdd = jsc.parallelize(list);

            Configuration conf = HBaseConfiguration.create();

            JavaHBaseContext hbaseContext = new JavaHBaseContext(jsc, conf);

            List resultList =
                    hbaseContext
                            .bulkGet(TableName.valueOf(tableName), 2, rdd, new GetFunction(), new ResultFunction())
                            .collect();
            for (int i = 0; i < resultList.size(); i++) {
                System.out.println(resultList.get(i));
            }
        } finally {
            jsc.stop();
        }
    }

    public static class GetFunction implements Function<byte[], Get> {
        private static final long serialVersionUID = 1L;

        public Get call(byte[] v) throws Exception {
            return new Get(v);
        }
    }

    public static class ResultFunction implements Function<Result, String> {
        private static final long serialVersionUID = 1L;

        public String call(Result result) throws Exception {
            Iterator<Cell> it = result.listCells().iterator();
            StringBuilder b = new StringBuilder();

            b.append(Bytes.toString(result.getRow())).append(":");

            while (it.hasNext()) {
                Cell cell = it.next();
                String q = Bytes.toString(cell.getQualifierArray());
                if (q.equals("counter")) {
                    b.append("(")
                            .append(Bytes.toString(cell.getQualifierArray()))
                            .append(",")
                            .append(Bytes.toLong(cell.getValueArray()))
                            .append(")");
                } else {
                    b.append("(")
                            .append(Bytes.toString(cell.getQualifierArray()))
                            .append(",")
                            .append(Bytes.toString(cell.getValueArray()))
                            .append(")");
                }
            }
            return b.toString();
        }
    }
}
