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SPL(Structured Process Language) A programming language specially for structured data computing.

There is a newer version: 20241126

package com.scudata.dw.compress;

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

import com.scudata.common.MessageManager;
import com.scudata.common.RQException;
import com.scudata.dw.BufferReader;
import com.scudata.resources.EngineMessage;

public class DoubleColumn extends Column {
	// ????Сֵ??ʾnull
	private static final double NULL = Double.NaN;
	
	// ???ݰ???洢??ÿ????Column.BLOCK_RECORD_COUNT????¼
	private ArrayList blockList = new ArrayList(1024);
	private int lastRecordCount = Column.BLOCK_RECORD_COUNT; // ???һ??ļ?¼??
	
	public void addData(Object data) {
		double value;
		if (data instanceof Number) {
			value = ((Number)data).doubleValue();
		} else if (data == null) {
			value = NULL;
		} else {
			// ???쳣
			MessageManager mm = EngineMessage.get();
			throw new RQException(mm.getMessage("ds.colTypeDif"));
		}
		
		if (lastRecordCount < Column.BLOCK_RECORD_COUNT) {
			double []block = blockList.get(blockList.size() - 1);
			block[lastRecordCount++] = value;
		} else {
			double []block = new double[Column.BLOCK_RECORD_COUNT];
			block[0] = value;
			blockList.add(block);
			lastRecordCount = 1;
		}
	}
	
	// ȡ??row?е?????
	public Object getData(int row) {
		// row?кţ???1??ʼ????
		row--;
		double []block = blockList.get(row / Column.BLOCK_RECORD_COUNT);
		double value = block[row % Column.BLOCK_RECORD_COUNT];
		if (Double.isNaN(value)) {
			return null;
		} else {
			return new Double(value);
		}
	}
	
	public Column clone() {
		return new DoubleColumn();
	}
	
	public void appendData(BufferReader br) throws IOException {
		addData(br.readObject());
	}
}