Some minor changes.

git-svn-id: https://svn.apache.org/repos/asf/jakarta/poi/trunk@352327 13f79535-47bb-0310-9956-ffa450edef68
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Glen Stampoultzis 2002-04-05 14:02:18 +00:00
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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" "../dtd/document-v11.dtd">
<!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="glens@apache.org" name="Glen Stampoultzis" id="GJS"/>
</authors>
</header>
<header>
<title>The New Halloween Document</title>
<authors>
<person email="acoliver2@users.sourceforge.net" name="Andrew C. Oliver" id="AO"/>
<person email="glens@apache.org" name="Glen Stampoultzis" id="GJS"/>
</authors>
</header>
<body>
<s1 title="How to use the HSSF prototype API">
<s2 title="Capabilities">
<p>This release of the how-to outlines functionality for 1.5.
Those looking for information on the release edition should
look in the poi-src for the release or at a
previous edition in CVS tagged for that release.</p>
<p>
This release allows numeric and string cell values to be written to
or read from an XLS file as well as reading and writing dates. Also
in this release is row and column sizing, cell styling (bold,
italics, borders,etc), and support for built-in data formats. New
to this release 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. It will also serve as the basis for the HSSF
Generator.</p>
</s2>
<s2 title="Target Audience">
<p>This release is intended for developers, java-fanatics and the
just generally all around impatient. HSSF has not yet been
extensively tested in a high load multi-threaded situation. This
release is not considered to be &quot;golden&quot; as it has new
features that have not been extensively tested, and is an early 2.0
build that could be restructured significantly in the future (not
that there are necessarily plans to do so, just that you're better
off basing your code on 1.0 and sticking with it if you don't need
2.0 stuff bad enough to deal with us pulling the rug out from under
you regularly).</p>
</s2>
<s2 title="Capabilities">
<p>This release of the how-to outlines functionality for the 1.5 release.
Those looking for information on previous releases should
look in the documentation distributed with that release.</p>
<p>
This release allows numeric and string cell values to be written to
or read from an XLS file as well as reading and writing dates. Also
in this release is row and column sizing, cell styling (bold,
italics, borders,etc), and support for built-in data formats. New
to this release 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. It will also serve as the basis for the HSSF
Generator.</p>
</s2>
<s2 title="General Use">
<s3 title="User API">
<s4 title="Writing a new one">
<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,&quot;SheetName&quot;).</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>
<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,&quot;SheetName&quot;).</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
@ -233,7 +220,7 @@ 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).
(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
@ -242,45 +229,46 @@ 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://cvs.apache.org/viewcvs/~checkout~/jakarta-poi/src/java/org/apache/poi/hssf/dev/HSSF.java?rev=1.1">org.apache.poi.hssf.dev.HSSF</link>.</p>
</s4> </s3>
</s4>
</s3>
<s3 title="Event API">
<p>The event API is brand new. 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>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(&quot;Workbook&quot;) 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>
<p>The event API is brand new. 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>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(&quot;Workbook&quot;) 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.
@ -391,11 +379,11 @@ documentation for the POIFS libraries as well.</p>
<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:
its code is repeated above. To run it:
</p>
<ul>
<li>download the poi-alpha build and untar it (tar xvzf
tarball.tar.gz)
tarball.tar.gz)
</li>
<li>set up your classpath as follows:
<code>export HSSFDIR={wherever you put HSSF's jar files}
@ -467,7 +455,7 @@ 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.
functions and a derivative.
</p>
<p>The first is &quot;biffview&quot;. To do this you run it (assumes
you have everything setup in your classpath and that you know what
@ -477,11 +465,11 @@ 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.
file and compare it.
</p>
<p>The second function is &quot;big freakin dump&quot;, just pass a
file and a second argument matching &quot;bfd&quot; exactly. This
will just make a big hexdump of the file.
will just make a big hexdump of the file.
</p>
<p>Lastly, there is &quot;mixed&quot; mode which does the same as
regular biffview, only it includes hex dumps of certain records
@ -511,7 +499,7 @@ more user feedback on what is most useful first we'll aim for that.
As a general principal, HSSF's goal is to support HSSF-Serializer
(meaning an emphasis on write). We would like to hear from you! How
are you using HSSF/POIFS? How would you like to use it? What features
are most important first?
are most important first?
</p>
</s3>