This topic shows you an example of how to use the batch
data stream (BDS) framework.
Before you begin
Identify the correct pattern to use. Select a pattern based
on what type of data stream you need. For example, if you want to
read text from a file, then select the FileReaderPattern. See
Batch data stream framework and patterns for a selection
of patterns.
Procedure
- Implement the pattern interface:
<codeblock>package com.ibm.websphere.samples;
import java.io.BufferedReader;
import java.io.IOException;
import java.util.Properties;
import com.ibm.websphere.batch.devframework.configuration.BDSFWLogger;
import com.ibm.websphere.batch.devframework.datastreams.patternadapter.FileReaderPattern;
// Implement the FileReaderPattern
public class TransactionListStream implements FileReaderPattern {
private Properties properties;
private BDSFWLogger logger;
/**
Save properties specified in the xJCL
*/
public void initialize(Properties props) {
// create logger
logger = new BDSFWLogger(props);
if (logger.isDebugEnabled())
logger.debug("entering TransactionListInputStream.initialize()");
properties = props;
}
// This method is where you should add the business logic of processing the read //string
public Object fetchRecord(BufferedReader reader) throws IOException {
String str = null;
Posting posting = null;
if (logger.isDebugEnabled())
logger.debug("Entering TransactionListInputStream.fetchRecord");
if(reader.ready()) {
str = reader.readLine();
}
if(str != null) {
posting = _generateRecord(str);
}
if (logger.isDebugEnabled())
logger.debug("Exiting TransactionListInputStream.fetchRecord with " + posting);
return posting;
}
// Helper method that parses the read string and creates an internal object for use
// by other parts of the code
private Posting _generateRecord(String str) {
Posting post = null;
String [] tokens = str.split(",", 3);
if(tokens.length == 3) {
String txTypeStr = tokens[0];
String actNoStr = tokens[1];
String amtStr = tokens[2];
int txType = Integer.parseInt(txTypeStr);
double amt = Double.parseDouble(amtStr);
post = new Posting(txType,actNoStr,amt);
} else {
logger.error("Invalid csv string" + str);
}
if(logger.isDebugEnabled())
logger.debug("Loaded posting record " + post);
return post;
}
public void processHeader(BufferedReader reader) throws IOException {
// NO OP for this sample
}
}
</codeblock>
- Reference the class that you created in the previous step,
along with the supporting class in the xJCL.
xJCL example
<codeblock><batch-data-streams>
<bds>
<logical-name>txlististream</logical-name>
<props>
<prop name="IMPLCLASS" value= "com.ibm.websphere.samples.TransactionListStream"/>
<prop name="FILENAME" value="/opt/inputfile.txt"/>
<prop name="debug" value="true"/>
</props>
<impl-class> com.ibm.websphere.batch.devframework.datastreams.patterns.TextFileReader </impl-class>
</bds>
</batch-data-streams>
</codeblock>
What to do next
Install the application.