ibm-information-center/dist/eclipse/plugins/i5OS.ic.rzahh_5.4.0.1/dtad.htm

104 lines
6.8 KiB
HTML

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html lang="en-us" xml:lang="en-us">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="security" content="public" />
<meta name="Robots" content="index,follow" />
<meta http-equiv="PICS-Label" content='(PICS-1.1 "http://www.icra.org/ratingsv02.html" l gen true r (cz 1 lz 1 nz 1 oz 1 vz 1) "http://www.rsac.org/ratingsv01.html" l gen true r (n 0 s 0 v 0 l 0) "http://www.classify.org/safesurf/" l gen true r (SS~~000 1))' />
<meta name="DC.Type" content="reference" />
<meta name="DC.Title" content="Data conversion and description" />
<meta name="abstract" content="The data conversion classes provide the capability to convert numeric and character data between iSeries and Java formats. Conversion may be needed when accessing iSeries data from a Java program. The data conversion classes support conversion of various numeric formats and between various EBCDIC code pages and Unicode." />
<meta name="description" content="The data conversion classes provide the capability to convert numeric and character data between iSeries and Java formats. Conversion may be needed when accessing iSeries data from a Java program. The data conversion classes support conversion of various numeric formats and between various EBCDIC code pages and Unicode." />
<meta name="copyright" content="(C) Copyright IBM Corporation 2006" />
<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 2006" />
<meta name="DC.Format" content="XHTML" />
<meta name="DC.Identifier" content="dtad" />
<meta name="DC.Language" content="en-us" />
<!-- All rights reserved. Licensed Materials Property of IBM -->
<!-- US Government Users Restricted Rights -->
<!-- Use, duplication or disclosure restricted by -->
<!-- GSA ADP Schedule Contract with IBM Corp. -->
<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
<link rel="stylesheet" type="text/css" href="./ic.css" />
<title>Data conversion and description</title>
</head>
<body id="dtad"><a name="dtad"><!-- --></a>
<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
<h1 class="topictitle1">Data conversion and description</h1>
<div><p>The <strong>data conversion</strong> classes provide the capability to convert
numeric and character data between iSeries™ and Java™ formats. Conversion may be needed
when accessing iSeries data
from a Java program. The data conversion classes support conversion
of various numeric formats and between various EBCDIC code pages and Unicode.</p>
<div class="section"><p>The <strong>data description</strong> classes build on the data conversion
classes to convert all fields in a record with a single method call. The
RecordFormat class allows the program to describe data that makes up a DataQueueEntry,
ProgramCall parameter, a record in a database file accessed through record-level
access classes, or any buffer of iSeries data. The Record class allows
the program to convert the contents of the record and access the data by
field name or index.</p>
<p>The <strong>converter</strong> classes provide fast and efficient
conversion between Java and your iSeries server. BinaryConverter converts
between Java byte arrays and Java simple types. CharConverter converts
between Java String objects and i5/OS™ code pages. For more information,
see the following:</p>
<blockquote><a href="progtipsperformance.htm#progtipsperformance__converters">Converters</a></blockquote>
</div>
<div class="section" id="dtad__datatypes"><a name="dtad__datatypes"><!-- --></a><h4 class="sectiontitle">Data types</h4><p>The <a href="javadoc/com/ibm/as400/access/AS400DataType.html#NAVBAR_TOP"> AS400DataType</a> is
an interface that defines the methods required for data conversion. A Java program
uses data types when individual pieces of data need to be converted. Conversion
classes exist for the following types of data:</p>
<ul><li><a href="dtadnum.htm#dtadnum">Numeric</a></li>
<li><a href="dtadtext.htm#dtadtext">Text (character)</a></li>
<li><a href="dtadcomp.htm#dtadcomp">Composite (numeric and text)</a></li>
</ul>
<p id="dtad__dtadexample"><a name="dtad__dtadexample"><!-- --></a><strong>Example: Using AS400DataType classes</strong></p>
<p>The
following example illustrates using AS400DataType classes with ProgramCall
to supply data for program parameters and to interpret the data returned
in program parameters.</p>
<blockquote><a href="dtxmp.htm#dtxmp">Example: Using
AS400DataType classes with ProgramCall</a></blockquote>
</div>
<div class="section" id="dtad__conversionspecifyingarecordformat"><a name="dtad__conversionspecifyingarecordformat"><!-- --></a><h4 class="sectiontitle">Conversion specifying
a record format</h4><p>The IBM<sup>®</sup> Toolbox for Java provides classes for building on the
data types classes to handle converting data one record at a time instead
of one field at a time. For example, suppose a Java program reads data off a data queue.
The data queue object returns a byte array of iSeries data to the Java program.
This array can potentially contain many types of iSeries data. The application can convert
one field at a time out of the byte array by using the data types classes,
or the program can create a record format that describes the fields in the
byte array. That record then does the conversion.</p>
<p>Record format conversion
can be useful when you are working with data from the program call, data
queue, and record-level access classes. The input and output from these classes
are byte arrays that can contain many fields of various types. Record format
converters can make it easier to convert this data between iSeries format
and Java format.</p>
<p>Conversion
through record format uses three classes:</p>
<ul><li><a href="dtadfld.htm#dtadfld">FieldDescription</a> classes identify
a field or parameter with a data type and a name.</li>
<li>A <a href="dtadrfmt.htm#dtadrfmt">RecordFormat</a> class describes
a group of fields.</li>
<li>A <a href="dtadrec.htm#dtadrec">Record</a> class joins the description
of a record (in the RecordFormat class) with the actual data.</li>
<li>A <a href="dtadldrw.htm#dtadldrw">LineDataRecordWriter</a> class
writes a record to an OutputStream in line data format</li>
</ul>
<p id="dtad__dtadconvexample"><a name="dtad__dtadconvexample"><!-- --></a><strong>Examples: Using record format conversion classes</strong></p>
<p>The
following examples illustrate using the record format conversion classes with
data queues:</p>
<blockquote><p><a href="dqproducerexample.htm#dqproducerexample">Using
the Record and RecordFormat classes to put data on a queue</a></p>
<p><a href="recordxmp.htm#recordxmp">Using the FieldDescription, RecordFormat,
and Record classes</a></p>
</blockquote>
</div>
</div>
</body>
</html>