Merge multiple files without BPM

[Former Member]

BpmPatternCollectMultiIf is classical BPM pattern used for n:1 scenario. A classic scenario is to pick multiple files(different format): merge and send single output to receiver. Obviously given its issues one will go for BPM only when no better option seems feasible. I am sure many would have come across same requirement and BPM seems to be the only Option.

In this blog I am discussing an approach with which BPM can be avoided.

btw I myself am guilty of creating BPM for similar requirement... picking 2 files(same folder), merging and posting IDOC to receiver. I now ask myself Why didn't I consider this approach back then!!! :razz:

Requirement:

• Read 2 files(XML/Text) from folder and merge and post data receiver.

Note: No message based correlation here. Just pick existing files and process.

Approach:

1) Read 2 Files using File sender adapter. One as MainPayload another as ApplicationAttachment

- Check Additional Files(s) and provide file name pattern

- Read 2nd file as mandatory(unless both files are available files will not be picked)

AttachmentFile1.optional

NO

Note: FCC cannot be used for both files. In such case one can use MessageTransformBean and PayloadSwapBean in Sender channel.

2) Create mapping to merge Main payload and Attachment(s)

- Do Check Read Attachments in Operation mapping

This is how we can merge the two:- MainDocument and ApplicationAttachment.

File1(Main Document)	File2(Attachment)	Result Structure (After Java mapping)
<?xml version="1.0" encoding="UTF-8"?> <ns0:MT_Sender xmlns:ns0="http://AttachmentTest">    <MainDoc>       <Row>          <StudentID>190</StudentID>          <StudentName>Lorum</StudentName>          <StudentStream>MS</StudentStream>       </Row>       <Row>          <StudentID>191</StudentID>          <StudentName>Ipsum</StudentName>          <StudentStream>B.Tech</StudentStream>       </Row>    </MainDoc> </ns0:MT_Sender>	<?xml version="1.0" encoding="UTF-8"?> <ns0:MT_Attachment xmlns:ns0="http://AttachmentTest">    <Attachment1>       <Row>          <StudentID>190</StudentID>          <CourseData> ... ... </CourseData>       </Row>       <Row>          <StudentID>192</StudentID>          <CourseData> ... ... </CourseData>       </Row>    </Attachment1> </ns0:MT_Attachment>	<?xml version="1.0" encoding="UTF-8"?> <ns0:MT_Intermediate xmlns:ns0="http://AttachmentTest/">    <MainDoc>       <Row>          <StudentID>190</StudentID>          <StudentName>Lorum</StudentName>          <StudentStream>MS</StudentStream>       </Row>       <Row>          <StudentID>191</StudentID>          <StudentName>Ipsum</StudentName>          <StudentStream>B.Tech</StudentStream>       </Row>    </MainDoc>    <Attachment1>       <Row>          <StudentID>190</StudentID>          <CourseData> ... ... </CourseData>       </Row>       <Row>          <StudentID>192</StudentID>          <CourseData> ... ... </CourseData>       </Row>    </Attachment1> </ns0:MT_Sender>

Sample Java Mapping Code

package com.sap.JavaMapping;

import java.io.*;

import java.util.*;

import javax.xml.parsers.*;

import javax.xml.transform.*;

import javax.xml.transform.dom.DOMSource;

import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.*;

import org.xml.sax.SAXException;

import com.sap.aii.mapping.api.*;

public class MergeAttachment extends AbstractTransformation{

  public void transform(TransformationInput in, TransformationOutput out)  throws StreamTransformationException

  {

  InputAttachments inputAttachments = in.getInputAttachments();

  InputStream inputstream = in.getInputPayload().getInputStream();

  OutputStream outputstream = out.getOutputPayload().getOutputStream();

  try {

  DocumentBuilderFactory dbfactory = DocumentBuilderFactory.newInstance();

  DocumentBuilder dbuilder = dbfactory.newDocumentBuilder();

  Document mainDoc = dbuilder.parse(inputstream);

  if(inputAttachments!=null)

  {

  if(inputAttachments.areAttachmentsAvailable())

  {

  Collection<String> collectionIDs  = inputAttachments.getAllContentIds(true);

  Object[] arrayObj  =collectionIDs.toArray();

  for(int i=0;i<arrayObj.length;i++)

  {

  String attachmentID = (String) arrayObj[i];

  Attachment attachment =inputAttachments.getAttachment(attachmentID);

  InputStream attachmentInputStream = new ByteArrayInputStream(attachment.getContent());

  Document attachmentDoc = dbuilder.parse(attachmentInputStream);

  Element element = (Element) attachmentDoc.getElementsByTagName("Attachment1").item(0);

  Node copiedNode = mainDoc.importNode(element, true);

  mainDoc.getDocumentElement().appendChild(copiedNode);

  }

  }

  }

  TransformerFactory tf = TransformerFactory.newInstance();

  Transformer transformer  = tf.newTransformer();

  transformer.transform(new DOMSource(mainDoc), new StreamResult(outputstream));

  } catch (ParserConfigurationException e) {

  this.getTrace().addInfo("ParserConfigurationException caught");

  e.printStackTrace();

  } catch (SAXException e) {

  this.getTrace().addInfo("SAXException caught");

  e.printStackTrace();

  } catch (IOException e) {

  this.getTrace().addInfo("IOException caught");

  e.printStackTrace();

  } catch (TransformerException e) {

  this.getTrace().addInfo("TransformerException caught");

  e.printStackTrace();

  }

  }

}

This code reads 2 xml document and merge attachment recordset below.

Please note following things:

- Read additional files option is only available for NFS not for FTP.

- Also in case Business system/location are different for sender file cannot be read as attachment.

Though using separate interface files can be brought to a common location and then this approach can be followed.

Let me know if this blog helps you.

This approach is also discussed in praveen.gujjeti blog N:1 & N:M mappings not possible without BPM