1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
|
<?xml version="1.0" encoding="UTF-8"?>
<!--
====================================================================
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
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
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.
====================================================================
-->
<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" "../dtd/document-v11.dtd">
<document>
<header>
<title>The New Halloween Document</title>
<authors>
<person email="acoliver2@users.sourceforge.net" name="Andrew C. Oliver" id="AO"/>
<person email="user@poi.apache.org" name="Glen Stampoultzis" id="GJS"/>
<person email="nick@apache.org" name="Nick Burch" id="NB"/>
<person email="sergeikozello@mail.ru" name="Sergei Kozello" id="SK"/>
</authors>
</header>
<body>
<section><title>How to use the HSSF API</title>
<section><title>Capabilities</title>
<p>This release of the how-to outlines functionality for the CVS HEAD.
Those looking for information on previous releases should
look in the documentation distributed with that release.</p>
<p>
HSSF allows numeric, string, date or formuala cell values to be written to
or read from an XLS file. Also
in this release is row and column sizing, cell styling (bold,
italics, borders,etc), and support for both built-in and user
defined data formats. Also available is
an event-based API for reading XLS files.
It differs greatly from the read/write API
and is intended for intermediate developers who need a smaller
memory footprint.
</p>
</section>
<section><title>Different APIs</title>
<p>There are a few different ways to access the HSSF API. These
have different characteristics, so you should read up on
all to select the best for you.</p>
<ul>
<li><link href="#user_api">User API</link></li>
<li><link href="#event_api">Event API</link></li>
<li><link href="#record_aware_event_api">Event API with extensions to be Record Aware</link></li>
<li><link href="#low_level_api">Low Level API</link></li>
</ul>
</section>
</section>
<section><title>General Use</title>
<anchor id="user_api" />
<section><title>User API</title>
<section><title>Writing a new file</title>
<p>The high level API (package: org.apache.poi.hssf.usermodel)
is what most people should use. Usage is very simple.
</p>
<p>Workbooks are created by creating an instance of
org.apache.poi.hssf.usermodel.HSSFWorkbook.
</p>
<p>Sheets are created by calling createSheet() from an existing
instance of HSSFWorkbook, the created sheet is automatically added in
sequence to the workbook. Sheets do not in themselves have a sheet
name (the tab at the bottom); you set
the name associated with a sheet by calling
HSSFWorkbook.setSheetName(sheetindex,"SheetName",encoding).
The name may be in 8bit format (HSSFWorkbook.ENCODING_COMPRESSED_UNICODE)
or Unicode (HSSFWorkbook.ENCODING_UTF_16). Default encoding is 8bit per char.
</p>
<p>Rows are created by calling createRow(rowNumber) from an existing
instance of HSSFSheet. Only rows that have cell values should be
added to the sheet. To set the row's height, you just call
setRowHeight(height) on the row object. The height must be given in
twips, or 1/20th of a point. If you prefer, there is also a
setRowHeightInPoints method.
</p>
<p>Cells are created by calling createCell(column, type) from an
existing HSSFRow. Only cells that have values should be added to the
row. Cells should have their cell type set to either
HSSFCell.CELL_TYPE_NUMERIC or HSSFCell.CELL_TYPE_STRING depending on
whether they contain a numeric or textual value. Cells must also have
a value set. Set the value by calling setCellValue with either a
String or double as a parameter. Individual cells do not have a
width; you must call setColumnWidth(colindex, width) (use units of
1/256th of a character) on the HSSFSheet object. (You can't do it on
an individual basis in the GUI either).</p>
<p>Cells are styled with HSSFCellStyle objects which in turn contain
a reference to an HSSFFont object. These are created via the
HSSFWorkbook object by calling createCellStyle() and createFont().
Once you create the object you must set its parameters (colors,
borders, etc). To set a font for an HSSFCellStyle call
setFont(fontobj).
</p>
<p>Once you have generated your workbook, you can write it out by
calling write(outputStream) from your instance of Workbook, passing
it an OutputStream (for instance, a FileOutputStream or
ServletOutputStream). You must close the OutputStream yourself. HSSF
does not close it for you.
</p>
<p>Here is some example code (excerpted and adapted from
org.apache.poi.hssf.dev.HSSF test class):</p>
<source><![CDATA[
short rownum;
// create a new file
FileOutputStream out = new FileOutputStream("workbook.xls");
// create a new workbook
HSSFWorkbook wb = new HSSFWorkbook();
// create a new sheet
HSSFSheet s = wb.createSheet();
// declare a row object reference
HSSFRow r = null;
// declare a cell object reference
HSSFCell c = null;
// create 3 cell styles
HSSFCellStyle cs = wb.createCellStyle();
HSSFCellStyle cs2 = wb.createCellStyle();
HSSFCellStyle cs3 = wb.createCellStyle();
HSSFDataFormat df = wb.createDataFormat();
// create 2 fonts objects
HSSFFont f = wb.createFont();
HSSFFont f2 = wb.createFont();
//set font 1 to 12 point type
f.setFontHeightInPoints((short) 12);
//make it blue
f.setColor( (short)0xc );
// make it bold
//arial is the default font
f.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
//set font 2 to 10 point type
f2.setFontHeightInPoints((short) 10);
//make it red
f2.setColor( (short)HSSFFont.COLOR_RED );
//make it bold
f2.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
f2.setStrikeout( true );
//set cell stlye
cs.setFont(f);
//set the cell format
cs.setDataFormat(df.getFormat("#,##0.0"));
//set a thin border
cs2.setBorderBottom(cs2.BORDER_THIN);
//fill w fg fill color
cs2.setFillPattern((short) HSSFCellStyle.SOLID_FOREGROUND);
//set the cell format to text see HSSFDataFormat for a full list
cs2.setDataFormat(HSSFDataFormat.getBuiltinFormat("text"));
// set the font
cs2.setFont(f2);
// set the sheet name in Unicode
wb.setSheetName(0, "\u0422\u0435\u0441\u0442\u043E\u0432\u0430\u044F " +
"\u0421\u0442\u0440\u0430\u043D\u0438\u0447\u043A\u0430",
HSSFWorkbook.ENCODING_UTF_16 );
// in case of compressed Unicode
// wb.setSheetName(0, "HSSF Test", HSSFWorkbook.ENCODING_COMPRESSED_UNICODE );
// create a sheet with 30 rows (0-29)
for (rownum = (short) 0; rownum < 30; rownum++)
{
// create a row
r = s.createRow(rownum);
// on every other row
if ((rownum % 2) == 0)
{
// make the row height bigger (in twips - 1/20 of a point)
r.setHeight((short) 0x249);
}
//r.setRowNum(( short ) rownum);
// create 10 cells (0-9) (the += 2 becomes apparent later
for (short cellnum = (short) 0; cellnum < 10; cellnum += 2)
{
// create a numeric cell
c = r.createCell(cellnum);
// do some goofy math to demonstrate decimals
c.setCellValue(rownum * 10000 + cellnum
+ (((double) rownum / 1000)
+ ((double) cellnum / 10000)));
String cellValue;
// create a string cell (see why += 2 in the
c = r.createCell((short) (cellnum + 1));
// on every other row
if ((rownum % 2) == 0)
{
// set this cell to the first cell style we defined
c.setCellStyle(cs);
// set the cell's string value to "Test"
c.setEncoding( HSSFCell.ENCODING_COMPRESSED_UNICODE );
c.setCellValue( "Test" );
}
else
{
c.setCellStyle(cs2);
// set the cell's string value to "\u0422\u0435\u0441\u0442"
c.setEncoding( HSSFCell.ENCODING_UTF_16 );
c.setCellValue( "\u0422\u0435\u0441\u0442" );
}
// make this column a bit wider
s.setColumnWidth((short) (cellnum + 1), (short) ((50 * 8) / ((double) 1 / 20)));
}
}
//draw a thick black border on the row at the bottom using BLANKS
// advance 2 rows
rownum++;
rownum++;
r = s.createRow(rownum);
// define the third style to be the default
// except with a thick black border at the bottom
cs3.setBorderBottom(cs3.BORDER_THICK);
//create 50 cells
for (short cellnum = (short) 0; cellnum < 50; cellnum++)
{
//create a blank type cell (no value)
c = r.createCell(cellnum);
// set it to the thick black border style
c.setCellStyle(cs3);
}
//end draw thick black border
// demonstrate adding/naming and deleting a sheet
// create a sheet, set its title then delete it
s = wb.createSheet();
wb.setSheetName(1, "DeletedSheet");
wb.removeSheetAt(1);
//end deleted sheet
// write the workbook to the output stream
// close our file (don't blow out our file handles
wb.write(out);
out.close();
]]></source>
</section>
<section><title>Reading or modifying an existing file</title>
<p>Reading in a file is equally simple. To read in a file, create a
new instance of org.apache.poi.poifs.Filesystem, passing in an open InputStream, such as a FileInputStream
for your XLS, to the constructor. Construct a new instance of
org.apache.poi.hssf.usermodel.HSSFWorkbook passing the
Filesystem instance to the constructor. From there you have access to
all of the high level model objects through their assessor methods
(workbook.getSheet(sheetNum), sheet.getRow(rownum), etc).
</p>
<p>Modifying the file you have read in is simple. You retrieve the
object via an assessor method, remove it via a parent object's remove
method (sheet.removeRow(hssfrow)) and create objects just as you
would if creating a new xls. When you are done modifying cells just
call workbook.write(outputstream) just as you did above.</p>
<p>An example of this can be seen in
<link href="http://svn.apache.org/repos/asf/poi/trunk/src/java/org/apache/poi/hssf/dev/HSSF.java">org.apache.poi.hssf.dev.HSSF</link>.</p>
</section>
</section>
<anchor id="event_api" />
<section><title>Event API</title>
<p>The event API is newer than the User API. It is intended for intermediate
developers who are willing to learn a little bit of the low level API
structures. Its relatively simple to use, but requires a basic
understanding of the parts of an Excel file (or willingness to
learn). The advantage provided is that you can read an XLS with a
relatively small memory footprint.
</p>
<p>One important thing to note with the basic Event API is that it
triggers events only for things actually stored within the file.
With the XLS file format, it is quite common for things that
have yet to be edited to simply not exist in the file. This means
there may well be apparent "gaps" in the record stream, which
you either need to work around, or use the
<link href="#record_aware_event_api">Record Aware</link> extension
to the Event API.</p>
<p>To use this API you construct an instance of
org.apache.poi.hssf.eventmodel.HSSFRequest. Register a class you
create that supports the
org.apache.poi.hssf.eventmodel.HSSFListener interface using the
HSSFRequest.addListener(yourlistener, recordsid). The recordsid
should be a static reference number (such as BOFRecord.sid) contained
in the classes in org.apache.poi.hssf.record. The trick is you
have to know what these records are. Alternatively you can call
HSSFRequest.addListenerForAllRecords(mylistener). In order to learn
about these records you can either read all of the javadoc in the
org.apache.poi.hssf.record package or you can just hack up a
copy of org.apache.poi.hssf.dev.EFHSSF and adapt it to your
needs. TODO: better documentation on records.</p>
<p>Once you've registered your listeners in the HSSFRequest object
you can construct an instance of
org.apache.poi.poifs.filesystem.FileSystem (see POIFS howto) and
pass it your XLS file inputstream. You can either pass this, along
with the request you constructed, to an instance of HSSFEventFactory
via the HSSFEventFactory.processWorkbookEvents(request, Filesystem)
method, or you can get an instance of DocumentInputStream from
Filesystem.createDocumentInputStream("Workbook") and pass
it to HSSFEventFactory.processEvents(request, inputStream). Once you
make this call, the listeners that you constructed receive calls to
their processRecord(Record) methods with each Record they are
registered to listen for until the file has been completely read.
</p>
<p>A code excerpt from org.apache.poi.hssf.dev.EFHSSF (which is
in CVS or the source distribution) is reprinted below with excessive
comments:</p>
<source><![CDATA[
/**
* This example shows how to use the event API for reading a file.
*/
public class EventExample
implements HSSFListener
{
private SSTRecord sstrec;
/**
* This method listens for incoming records and handles them as required.
* @param record The record that was found while reading.
*/
public void processRecord(Record record)
{
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)
{
System.out.println("Encountered workbook");
// assigned to the class level member
} else if (bof.getType() == bof.TYPE_WORKSHEET)
{
System.out.println("Encountered sheet reference");
}
break;
case BoundSheetRecord.sid:
BoundSheetRecord bsr = (BoundSheetRecord) record;
System.out.println("New sheet named: " + bsr.getSheetname());
break;
case RowRecord.sid:
RowRecord rowrec = (RowRecord) record;
System.out.println("Row found, first column at "
+ rowrec.getFirstCol() + " last column at " + rowrec.getLastCol());
break;
case NumberRecord.sid:
NumberRecord numrec = (NumberRecord) record;
System.out.println("Cell found with value " + numrec.getValue()
+ " at row " + numrec.getRow() + " and column " + numrec.getColumn());
break;
// SSTRecords store a array of unique strings used in Excel.
case SSTRecord.sid:
sstrec = (SSTRecord) record;
for (int k = 0; k < sstrec.getNumUniqueStrings(); k++)
{
System.out.println("String table value " + k + " = " + sstrec.getString(k));
}
break;
case LabelSSTRecord.sid:
LabelSSTRecord lrec = (LabelSSTRecord) record;
System.out.println("String cell found with value "
+ sstrec.getString(lrec.getSSTIndex()));
break;
}
}
/**
* Read an excel file and spit out what we find.
*
* @param args Expect one argument that is the file to read.
* @throws IOException When there is an error processing the file.
*/
public static void main(String[] args) throws IOException
{
// create a new file input stream with the input file specified
// at the command line
FileInputStream fin = new FileInputStream(args[0]);
// create a new org.apache.poi.poifs.filesystem.Filesystem
POIFSFileSystem poifs = new POIFSFileSystem(fin);
// get the Workbook (excel part) stream in a InputStream
InputStream din = poifs.createDocumentInputStream("Workbook");
// construct out HSSFRequest object
HSSFRequest req = new HSSFRequest();
// lazy listen for ALL records with the listener shown above
req.addListenerForAllRecords(new EventExample());
// create our event factory
HSSFEventFactory factory = new HSSFEventFactory();
// process our events based on the document input stream
factory.processEvents(req, din);
// once all the events are processed close our file input stream
fin.close();
// and our document input stream (don't want to leak these!)
din.close();
System.out.println("done.");
}
}
]]></source>
</section>
<anchor id="record_aware_event_api" />
<section><title>Record Aware Event API</title>
<p>
This is an experimental extension to the normal
<link href="#event_api">Event API</link>. With this, your listener
will be called with extra, dummy records. These dummy records should
alert you to records which aren't present in the file (eg cells that have
yet to be edited), and allow you to handle these.
</p>
<p>
There are three dummy records that your HSSFListener will be called with:
</p>
<ul>
<li>org.apache.poi.hssf.eventusermodel.dummyrecord.MissingRowDummyRecord
<br />
This is called during the row record phase (which typically occurs before
the cell records), and indicates that the row record for the given
row is not present in the file.</li>
<li>org.apache.poi.hssf.eventusermodel.dummyrecord.MissingCellDummyRecord
<br />
This is called during the cell record phase. It is called when a cell
record is encountered which leaves a gap between it an the previous one.
You can get multiple of these, before the real cell record.</li>
<li>org.apache.poi.hssf.eventusermodel.dummyrecord.LastCellOfRowDummyRecord
<br />
This is called after the last cell of a given row. It indicates that there
are no more cells for the row, and also tells you how many cells you have
had. For a row with no cells, this will be the only record you get.</li>
</ul>
<p>
To use the Record Aware Event API, you should create an
org.apache.poi.hssf.eventusermodel.MissingRecordAwareHSSFListener, and pass
it your HSSFListener. Then, register the MissingRecordAwareHSSFListener
to the event model, and start that as normal.
</p>
<p>
One example use for this API is to write a CSV outputter, which always
outputs a minimum number of columns, even where the file doesn't contain
some of the rows or cells. It can be found at
<code>/src/scratchpad/examples/src/org/apache/poi/hssf/eventusermodel/examples/XLS2CSVmra.java</code>,
and may be called on the command line, or from within your own code.
The latest version is always available from
<link href="http://svn.apache.org/repos/asf/poi/trunk/src/scratchpad/examples/src/org/apache/poi/hssf/eventusermodel/examples/">subversion</link>.
</p>
<p>
<em>This code is currently in the scratchpad section, so you will either
need to include the scratchpad jar on your classpath, or build from a</em>
<link href="../subversion.html">subversion checkout</link>.
</p>
</section>
<anchor id="low_level_api" />
<section><title>Low Level APIs</title>
<p>The low level API is not much to look at. It consists of lots of
"Records" in the org.apache.poi.hssf.record.* package,
and set of helper classes in org.apache.poi.hssf.model.*. The
record classes are consistent with the low level binary structures
inside a BIFF8 file (which is embedded in a POIFS file system). You
probably need the book: "Microsoft Excel 97 Developer's Kit"
from Microsoft Press in order to understand how these fit together
(out of print but easily obtainable from Amazon's used books). In
order to gain a good understanding of how to use the low level APIs
should view the source in org.apache.poi.hssf.usermodel.* and
the classes in org.apache.poi.hssf.model.*. You should read the
documentation for the POIFS libraries as well.</p>
</section>
<section><title>Generating XLS from XML</title>
<p>If you wish to generate an XLS file from some XML, it is possible to
write your own XML processing code, then use the User API to write out
the document.</p>
<p>The other option is to use <link href="http://cocoon.apache.org/">Cocoon</link>.
In Cocoon, there is the <link href="http://cocoon.apache.org/2.1/userdocs/xls-serializer.html">HSSF Serializer</link>,
which takes in XML (in the gnumeric format), and outputs an XLS file for you.</p>
</section>
<section><title>HSSF Class/Test Application</title>
<p>The HSSF application is nothing more than a test for the high
level API (and indirectly the low level support). The main body of
its code is repeated above. To run it:
</p>
<ul>
<li>download the poi-alpha build and untar it (tar xvzf
tarball.tar.gz)
</li>
<li>set up your classpath as follows:
<code>export HSSFDIR={wherever you put HSSF's jar files}
export LOG4JDIR={wherever you put LOG4J's jar files}
export CLASSPATH=$CLASSPATH:$HSSFDIR/hssf.jar:$HSSFDIR/poi-poifs.jar:$HSSFDIR/poi-util.jar:$LOG4JDIR/jog4j.jar</code>
</li><li>type:
<code>java org.apache.poi.hssf.dev.HSSF ~/myxls.xls write</code></li>
</ul>
<p></p>
<p>This should generate a test sheet in your home directory called <code>"myxls.xls"</code>. </p>
<ul>
<li>Type:
<code>java org.apache.poi.hssf.dev.HSSF ~/input.xls output.xls</code>
<br/>
<br/>
This is the read/write/modify test. It reads in the spreadsheet, modifies a cell, and writes it back out.
Failing this test is not necessarily a bad thing. If HSSF tries to modify a non-existant sheet then this will
most likely fail. No big deal. </li>
</ul>
</section>
<section><title>Logging facility</title>
<p>POI can dynamically select its logging implementation. POI tries to
create a logger using the System property named "org.apache.poi.util.POILogger".
Out of the box this can be set to one of three values:
</p>
<ul>
<li>org.apache.poi.util.CommonsLogger</li>
<li>org.apache.poi.util.NullLogger</li>
<li>org.apache.poi.util.SystemOutLogger</li>
</ul>
<p>
If the property is not defined or points to an invalid classthen the NullLogger is used.
</p>
<p>
Refer to the commons logging package level javadoc for more information concerning how to
<link href="http://jakarta.apache.org/commons/logging/api/index.html">configure commons logging.</link>
</p>
</section>
<section><title>HSSF Developer's Tools</title>
<p>HSSF has a number of tools useful for developers to debug/develop
stuff using HSSF (and more generally XLS files). We've already
discussed the app for testing HSSF read/write/modify capabilities;
now we'll talk a bit about BiffViewer. Early on in the development of
HSSF, it was decided that knowing what was in a record, what was
wrong with it, etc. was virtually impossible with the available
tools. So we developed BiffViewer. You can find it at
org.apache.poi.hssf.dev.BiffViewer. It performs two basic
functions and a derivative.
</p>
<p>The first is "biffview". To do this you run it (assumes
you have everything setup in your classpath and that you know what
you're doing enough to be thinking about this) with an xls file as a
parameter. It will give you a listing of all understood records with
their data and a list of not-yet-understood records with no data
(because it doesn't know how to interpret them). This listing is
useful for several things. First, you can look at the values and SEE
what is wrong in quasi-English. Second, you can send the output to a
file and compare it.
</p>
<p>The second function is "big freakin dump", just pass a
file and a second argument matching "bfd" exactly. This
will just make a big hexdump of the file.
</p>
<p>Lastly, there is "mixed" mode which does the same as
regular biffview, only it includes hex dumps of certain records
intertwined. To use that just pass a file with a second argument
matching "on" exactly.</p>
<p>In the next release cycle we'll also have something called a
FormulaViewer. The class is already there, but its not very useful
yet. When it does something, we'll document it.</p>
</section>
<section><title>What's Next?</title>
<p>Further effort on HSSF is going to focus on the following major areas: </p>
<ul>
<li>Performance: POI currently uses a lot of memory for large sheets.</li>
<li>Charts: This is a hard problem, with very little documentation.</li>
</ul>
<p><link href="../getinvolved/index.html"> So jump in! </link> </p>
</section>
</section>
</body>
</document>
|
