com.bah.culvert.tableadapters.HBaseLocalTableAdapter.java Source code

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Here is the source code for com.bah.culvert.tableadapters.HBaseLocalTableAdapter.java

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/**
 * Copyright 2011 Booz Allen Hamilton.
 * 
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership. Booz Allen Hamilton
 * 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.bah.culvert.tableadapters;

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

import org.apache.commons.collections.iterators.EmptyIterator;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.coprocessor.BaseEndpointCoprocessor;
import org.apache.hadoop.hbase.coprocessor.RegionCoprocessorEnvironment;
import org.apache.hadoop.hbase.regionserver.HRegion;
import org.apache.hadoop.hbase.regionserver.InternalScanner;

import com.bah.culvert.adapter.LocalTableAdapter;
import com.bah.culvert.adapter.RemoteOp;
import com.bah.culvert.data.CColumn;
import com.bah.culvert.data.CKeyValue;
import com.bah.culvert.data.CRange;
import com.bah.culvert.data.Result;
import com.bah.culvert.transactions.Get;

/**
 * Adapter for the local hbase table when doing a {@link RemoteOp}
 */
public class HBaseLocalTableAdapter extends LocalTableAdapter {
    /**
     * Reference to the BaseEndpointCoprocessor so that we have access to the
     * environment.
     */
    private final BaseEndpointCoprocessor ENDPOINT;

    public HBaseLocalTableAdapter(BaseEndpointCoprocessor endpoint) {
        this.ENDPOINT = endpoint;
    }

    @Override
    public Iterator<Result> get(Get get) {
        // Get the range list
        List<CRange> culvertRangeList = get.getRanges();

        // Only scan the tables if we have a range
        if (culvertRangeList.size() > 0) {

            List<Result> results = new ArrayList<Result>();

            // Get the reference to the HRegion
            HRegion hregion = null;
            try {
                hregion = ((RegionCoprocessorEnvironment) this.ENDPOINT.getEnvironment()).getRegion();
            } catch (Exception e) {
                throw new RuntimeException(this.getTableName() + " Unable to get HRegion", e);
            }
            try {
                // Loop through the ranges
                for (CRange cr : culvertRangeList) {
                    Scan scan = new Scan(cr.getStart(), cr.getEnd());
                    // add columns to the scanner
                    for (CColumn cc : get.getColumns()) {
                        scan.addColumn(cc.getColumnFamily(), cc.getColumnQualifier());
                    }
                    InternalScanner scanner = hregion.getScanner(scan);
                    try {
                        List<KeyValue> curVals = new ArrayList<KeyValue>();
                        boolean hasMore = false;
                        do {
                            curVals.clear();
                            hasMore = scanner.next(curVals);
                            KeyValue kv = curVals.get(0);
                            results.add(new Result(kv.getRow(), new CKeyValue(kv.getKey(), kv.getFamily(),
                                    kv.getQualifier(), kv.getTimestamp(), kv.getValue())));
                        } while (hasMore);
                    } finally {
                        scanner.close();
                    }
                }
            } catch (IOException e) {
                throw new RuntimeException(this.getTableName() + " Failed to iterate through table", e);
            }

            return results.iterator();
        }
        // There were no ranges in the list, so return an empty iterator
        return EmptyIterator.INSTANCE;
    }

    @Override
    public byte[] getStartKey() {
        // Get the reference to the HRegion
        HRegion hregion = null;
        try {
            hregion = ((RegionCoprocessorEnvironment) ENDPOINT.getEnvironment()).getRegion();
        } catch (Exception e) {
            throw new RuntimeException(getTableName() + " Unable to get HRegion", e);
        }

        return hregion.getStartKey();
    }

    @Override
    public byte[] getEndKey() {
        // Get the reference to the HRegion
        HRegion hregion = null;
        try {
            hregion = ((RegionCoprocessorEnvironment) ENDPOINT.getEnvironment()).getRegion();
        } catch (Exception e) {
            throw new RuntimeException(getTableName() + " Unable to get HRegion", e);
        }

        return hregion.getEndKey();
    }
}