missingrecordawarehssflistener.java

来自「EXCEL read and write」· Java 代码 · 共 166 行

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   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
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       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,
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   See the License for the specific language governing permissions and
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package org.apache.poi.hssf.eventusermodel;

import org.apache.poi.hssf.eventusermodel.dummyrecord.LastCellOfRowDummyRecord;
import org.apache.poi.hssf.eventusermodel.dummyrecord.MissingCellDummyRecord;
import org.apache.poi.hssf.eventusermodel.dummyrecord.MissingRowDummyRecord;
import org.apache.poi.hssf.record.BOFRecord;
import org.apache.poi.hssf.record.CellValueRecordInterface;
import org.apache.poi.hssf.record.NoteRecord;
import org.apache.poi.hssf.record.Record;
import org.apache.poi.hssf.record.RowRecord;
import org.apache.poi.hssf.record.SharedFormulaRecord;

/**
 * <p>A HSSFListener which tracks rows and columns, and will
 *  trigger your HSSFListener for all rows and cells,
 *  even the ones that aren't actually stored in the file.</p>
 * <p>This allows your code to have a more "Excel" like
 *  view of the data in the file, and not have to worry
 *  (as much) about if a particular row/cell is in the
 *  file, or was skipped from being written as it was
 *  blank.
 */
public final class MissingRecordAwareHSSFListener implements HSSFListener {
	private HSSFListener childListener;
	
	// Need to have different counters for cell rows and
	//  row rows, as you sometimes get a RowRecord in the
	//  middle of some cells, and that'd break everything
	private int lastRowRow;
	
	private int lastCellRow;
	private int lastCellColumn;
	
	/**
	 * Constructs a new MissingRecordAwareHSSFListener, which
	 *  will fire processRecord on the supplied child
	 *  HSSFListener for all Records, and missing records.
	 * @param listener The HSSFListener to pass records on to
	 */
	public MissingRecordAwareHSSFListener(HSSFListener listener) {
		resetCounts();
		childListener = listener;
	}

	public void processRecord(Record record) {
		int thisRow;
		int thisColumn;


		if (record instanceof CellValueRecordInterface) {
			CellValueRecordInterface valueRec = (CellValueRecordInterface) record;
			thisRow = valueRec.getRow();
			thisColumn = valueRec.getColumn();
		} else {
			thisRow = -1;
			thisColumn = -1;

			switch (record.getSid()) {
				// the BOFRecord can represent either the beginning of a sheet or
				// the workbook
				case BOFRecord.sid:
					BOFRecord bof = (BOFRecord) record;
					if (bof.getType() == bof.TYPE_WORKBOOK || bof.getType() == bof.TYPE_WORKSHEET) {
						// Reset the row and column counts - new workbook / worksheet
						resetCounts();
					}
					break;
				case RowRecord.sid:
					RowRecord rowrec = (RowRecord) record;
					//System.out.println("Row " + rowrec.getRowNumber() + " found, first column at "
					//        + rowrec.getFirstCol() + " last column at " + rowrec.getLastCol());

					// If there's a jump in rows, fire off missing row records
					if (lastRowRow + 1 < rowrec.getRowNumber()) {
						for (int i = (lastRowRow + 1); i < rowrec.getRowNumber(); i++) {
							MissingRowDummyRecord dr = new MissingRowDummyRecord(i);
							childListener.processRecord(dr);
						}
					}

					// Record this as the last row we saw
					lastRowRow = rowrec.getRowNumber();
					break;

				case SharedFormulaRecord.sid:
					// SharedFormulaRecord occurs after the first FormulaRecord of the cell range.
					// There are probably (but not always) more cell records after this
					// - so don't fire off the LastCellOfRowDummyRecord yet
					childListener.processRecord(record);
					return;
				case NoteRecord.sid:
					NoteRecord nrec = (NoteRecord) record;
					thisRow = nrec.getRow();
					thisColumn = nrec.getColumn();
					break;
			}
		}
		// If we're on cells, and this cell isn't in the same
		//  row as the last one, then fire the 
		//  dummy end-of-row records
		if(thisRow != lastCellRow && lastCellRow > -1) {
			for(int i=lastCellRow; i<thisRow; i++) {
				int cols = -1;
				if(i == lastCellRow) {
					cols = lastCellColumn;
				}
				childListener.processRecord(new LastCellOfRowDummyRecord(i, cols));
			}
		}
		
		// If we've just finished with the cells, then fire the
		// final dummy end-of-row record
		if(lastCellRow != -1 && lastCellColumn != -1 && thisRow == -1) {
			childListener.processRecord(new LastCellOfRowDummyRecord(lastCellRow, lastCellColumn));
			
			lastCellRow = -1;
			lastCellColumn = -1;
		}
		
		// If we've moved onto a new row, the ensure we re-set
		//  the column counter
		if(thisRow != lastCellRow) {
			lastCellColumn = -1;
		}
		
		// If there's a gap in the cells, then fire
		//  the dummy cell records
		if(lastCellColumn != thisColumn-1) {
			for(int i=lastCellColumn+1; i<thisColumn; i++) {
				childListener.processRecord(new MissingCellDummyRecord(thisRow, i));
			}
		}
		
		// Update cell and row counts as needed
		if(thisColumn != -1) {
			lastCellColumn = thisColumn;
			lastCellRow = thisRow;
		}

		childListener.processRecord(record);
	}

	private void resetCounts() {
		lastRowRow = -1;
		lastCellRow = -1;
		lastCellColumn = -1;
	}
}