Example usage for org.apache.poi.xssf.streaming SXSSFSheet getWorkbook

Introduction

In this page you can find the example usage for org.apache.poi.xssf.streaming SXSSFSheet getWorkbook.

Prototype

@Override
public SXSSFWorkbook getWorkbook() 

Source Link

Document

Return the parent workbook

Usage

From source file:org.apache.metamodel.excel.ExcelUpdateCallbackTest.java

License:Apache License

public void testStreamingAPI() throws Exception {
    File file = new File("target/streaming-api-test.xlsx");
    if (file.exists()) {
        file.delete();//from w  ww .  j av  a2 s .  c o m
    }

    assertFalse(file.exists());

    // write using streaming writer
    {
        ExcelDataContext dc = new ExcelDataContext(file);
        ExcelUpdateCallback callback = new ExcelUpdateCallback(dc);

        SXSSFSheet sheet = (SXSSFSheet) callback.createSheet("foobar");

        Field windowSizeField = SXSSFSheet.class.getDeclaredField("_randomAccessWindowSize");
        windowSizeField.setAccessible(true);
        int windowSize = windowSizeField.getInt(sheet);
        assertEquals(1000, windowSize);

        Field rowsField = SXSSFSheet.class.getDeclaredField("_rows");
        rowsField.setAccessible(true);
        @SuppressWarnings("unchecked")
        Map<Integer, SXSSFRow> rows = (Map<Integer, SXSSFRow>) rowsField.get(sheet);
        assertEquals(0, rows.size());

        // create 5x the amound of rows as the streaming sheet will hold in
        // memory
        for (int i = 0; i < windowSize * 5; i++) {
            Row row = sheet.createRow(i);
            Cell cell = row.createCell(0);
            cell.setCellValue("value" + i);

            assertTrue(rows.size() <= 1000);
        }

        assertEquals(1000, rows.size());

        ExcelUtils.writeAndCloseWorkbook(dc, sheet.getWorkbook());
    }

    assertTrue("Usually the file size will be circa 42000, but it was: " + file.length(),
            file.length() > 40000 && file.length() < 45000);

    // read to check results
    {
        ExcelDataContext dc = new ExcelDataContext(file);
        assertEquals("[foobar]", Arrays.toString(dc.getDefaultSchema().getTableNames()));

        Table table = dc.getDefaultSchema().getTableByName("foobar");

        assertEquals("[value0]", Arrays.toString(table.getColumnNames()));

        DataSet ds = dc.query().from(table).select("value0").execute();
        int recordNo = 1;
        while (ds.next()) {
            assertEquals("value" + recordNo, ds.getRow().getValue(0));
            recordNo++;
        }

        assertEquals(5000, recordNo);
    }
}

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