RowDataPacketGrouper.java

package org.opencloudb.mpp;

import java.util.Arrays;
import java.util.Collection;
import java.util.LinkedList;

import org.opencloudb.net.mysql.RowDataPacket;
import org.opencloudb.util.ByteUtil;
import org.opencloudb.util.LongUtil;

/**
 * implement group function select a,count(*),sum(*) from A group by a
 * 
 * @author wuzhih
 * 
 */
public class RowDataPacketGrouper {

	private final MergeCol[] mergCols;
	private final int[] groupColumnIndexs;
	private Collection<RowDataPacket> result = new LinkedList<RowDataPacket>();

	public RowDataPacketGrouper(int[] groupColumnIndexs, MergeCol[] mergCols) {
		super();
		this.groupColumnIndexs = groupColumnIndexs;
		this.mergCols = mergCols;
	}

	public Collection<RowDataPacket> getResult() {
		return result;
	}

	public void addRow(RowDataPacket rowDataPkg) {

		for (RowDataPacket row : result) {
			if (sameGropuColums(rowDataPkg, row)) {
				aggregateRow(row, rowDataPkg);
				return;
			}
		}
		// not aggreated ,insert new
		result.add(rowDataPkg);

	}

	private void aggregateRow(RowDataPacket toRow, RowDataPacket newRow) {
		if (mergCols == null) {
			return;
		}
		for (MergeCol merg : mergCols) {

			byte[] result = mertFields(
					toRow.fieldValues.get(merg.colMeta.colIndex),
					newRow.fieldValues.get(merg.colMeta.colIndex),
					merg.colMeta.colType, merg.mergeType);
			if (result != null) {
				toRow.fieldValues.set(merg.colMeta.colIndex, result);
			}
		}

	}

	private byte[] mertFields(byte[] bs, byte[] bs2, int colType, int mergeType) {
		// System.out.println("mergeType:"+ mergeType+" colType "+colType+
		// " field:"+Arrays.toString(bs)+ " ->  "+Arrays.toString(bs2));
		switch (mergeType) {
		case MergeCol.MERGE_SUM:
		case MergeCol.MERGE_COUNT: {
			long s1 = Long.parseLong(new String(bs));
			long s2 = Long.parseLong(new String(bs2));
			long total = s1 + s2;
			return LongUtil.toBytes(total);
		}
		case MergeCol.MERGE_MAX: {
			// int compare = ByteUtil.compareNumberArray(bs, bs2);
			// return (compare > 0) ? bs : bs2;
			return ByteUtil.compareNumberArray2(bs, bs2, 1);
		}
		case MergeCol.MERGE_MIN: {
			// int compare = ByteUtil.compareNumberArray(bs, bs2);
			// return (compare > 0) ? bs2 : bs;
			return ByteUtil.compareNumberArray2(bs, bs2, 2);
		}
		default:
			return null;
		}

	}

	// private static final

	private boolean sameGropuColums(RowDataPacket newRow, RowDataPacket existRow) {
		if (groupColumnIndexs == null) {// select count(*) from aaa , or group
										// column
			return true;
		}
		for (int i = 0; i < groupColumnIndexs.length; i++) {
			if (!Arrays.equals(newRow.fieldValues.get(groupColumnIndexs[i]),
					existRow.fieldValues.get(groupColumnIndexs[i]))) {
				return false;
			}

		}
		return true;

	}
}