b48b9c9344
git-svn-id: https://svn.apache.org/repos/asf/jakarta/poi/trunk@352175 13f79535-47bb-0310-9956-ffa450edef68
115 lines
4.7 KiB
XML
115 lines
4.7 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.0//EN" "../dtd/document-v10.dtd">
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<document>
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<header>
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<title>Record Generator HOWTO</title>
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<authors>
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<person email="glens@apache.org" name="Glen Stampoultzis" id="glens"/>
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<person email="acoliver@apache.org" name="Andrew C. Oliver" id="acoliver"/>
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</authors>
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</header>
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<body>
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<s1 title="How to Use the Record Generator">
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<s2 title="History">
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<p>
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The record generator was born from frustration with translating
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the Excel records to Java classes. Doing this manually is a time
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consuming process. It's also very easy to make mistakes.
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</p>
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<p>
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A utility was needed to take the defintition of what a
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record looked like and do all the boring stuff. Thus the
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record generator was born.
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</p>
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</s2>
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<s2 title="Capabilities">
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<p>
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The record generator takes XML as input and produced the following
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output:
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<ul>
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<li>A Java file capabile of decoding and encoding the record.</li>
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<li>A test class with provides a fill-in-the-blanks implementation of a test case
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for ensuring the record operates as designed.</li>
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</ul>
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</p>
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</s2>
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<s2 title="Usage">
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<p>
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The record generator is invoked as an Ant target (generate-records). It goes
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through looking for all files in src/records/defintitions ending with _record.xml.
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It then creates two files; the Java record definition and the Java test case template.
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</p>
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<p>
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The records themselves have the following general layout:
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</p>
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<source><![CDATA[
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<record id="0x1032" name="Frame" package="org.apache.poi.hssf.record">
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<description>The frame record indicates whether there is a border
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around the displayed text of a chart.</description>
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<author>Glen Stampoultzis (glens at apache.org)</author>
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<fields>
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<field type="int" size="2" name="border type">
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<const name="regular" value="0" description="regular rectangle or no border"/>
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<const name="shadow" value="1" description="rectangle with shadow"/>
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</field>
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<field type="int" size="2" name="options">
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<bit number="0" name="auto size"
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description="excel calculates the size automatically if true"/>
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<bit number="1" name="auto position"
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description="excel calculates the position automatically"/>
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</field>
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</fields>
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</record>
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]]></source>
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<p>
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Currently the type can be of type int, float or string. The 'int'
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type covers bytes, shorts and integers which is selected using a
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size of 1, 2 or 4. An additional type called varword is used to
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represent a array of word values where the first short is the length
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of the array. The string type generation is only partially
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implemented. If choosing string you must select a size of 'var'.
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</p>
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<p>
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The Java records are regenerated each time the record generator is
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run, however the test stubs are only created if the test stub does
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not already exist. What this means is that you may change test
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stubs but not the generated records.
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</p>
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</s2>
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<s2 title="How it Works">
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<p>
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The record generation works by taking an XML file and styling it
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using XLST. Given that XSLT is a little limited in some ways it was
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necessary to add a little Java code to the mix.
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</p>
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<p>
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See record.xsl, record_test.xsl, FieldIterator.java,
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RecordUtil.java, RecordGenerator.java
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</p>
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</s2>
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<s2 title="Limitations">
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<p>
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The record generator does not handle all possible record types and
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is not ment to. Sometimes it's going to make more sense to generate
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the records manually. The main point of this thing is to make the
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easy stuff simple.
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</p>
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<p>
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Currently the record generator is optimized to create Excel records.
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It could be adapted to create Word records with a little poking
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around.
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</p>
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<p>
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Currently the the XSL file that generates the record calls out to
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Java objects. This would have been better done as Javascript inside
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the XSL file itself. The Java code for the record generation is
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currently quite messy with minimal comments.
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</p>
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</s2>
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</s1>
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</body>
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</document>
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