Using the batch data stream framework

Before you start this task, you must identify the correct pattern to use. Select a pattern based on the type of data stream you need to use. For example, if you want to read text from a file, then select the FileReaderPattern. See Implementing batch data stream framework and patterns for a description of the available patterns

1. 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>

2. Add a reference to the class that you just created in the previous step, along with the supporting class in the xJCL.

   <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>