Use Cases for Petals-SE-JSR181

Version 6 by Vincent Zurczak
on Apr 03, 2012 18:34.

<< Changes from 5 to 6

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Version 7 by Vincent Zurczak
on Apr 10, 2012 18:42.

Changes from 7 to 8 >>

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h1. Implementing a web method that deals with complex types and attachments

This example is an upload method: it receives path + file name information (where to store the file) as a parameter, and a file to upload (as a binary attachment).

h2. Text File Extraction

Note that the example contains a bug workaround (as of Petals 4 early releases) : the 1st attachment, if any, is ignored as it contains... a copy of the payload + soap envelope (sic). This may be fixed in your Petals release (and this hack should disappear from this doc as soon as the fix is spread enough).

This example receives a text file as an attachment and returns its content to the client.
Attachment's style is MTOM.

{code}
package com.ebmwebsourcing;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import javax.activation.DataHandler;
import javax.jws.WebMethod;
import javax.jws.WebResult;
import javax.jws.WebService;
import javax.xml.ws.BindingType;
import javax.xml.ws.soap.SOAPBinding;

/**
* Here is a sample JAX-WS implementation.
*/
@WebService( serviceName="Test", targetNamespace="http://ebmwebsourcing.com", portName="TestPort" )
@BindingType(SOAPBinding.SOAP11HTTP_MTOM_BINDING)
public class Test {

/* (non-Javadoc)
* @see JaxWSInterface#HelloWorld()
*/
@WebMethod( operationName="extractContent" )
@WebResult( name="returnMessage" )
public String extractContent( DataHandler textDocument ) {

String result = "An error occurred.";
ByteArrayOutputStream os = new ByteArrayOutputStream();
try {
copyStream( textDocument.getInputStream(), os );
result = os.toString( "UTF-8" );

} catch (IOException e) {
e.printStackTrace();
}

return result;
}

/**
* Copies the content from in into os.
* 
* Neither in nor os are closed by this method. 
* They must be explicitly closed after this method is called.
* 
*
* @param in
* @param os
* @throws IOException
*/
public static void copyStream( InputStream in, OutputStream os ) throws IOException {

byte[] buf = new byte[ 1024 ];
int len;
while((len = in.read( buf )) > 0) {
os.write( buf, 0, len );
}
}
}
{code}

h2. Upload method in SU main class (JAX-WS annotated)

This example is an upload method: it receives path + file name information (where to store the file) as a parameter, and a file to upload (as a binary attachment). In this example, we retrieve attachments directly from the Petals exchange.

{code}
@WebMethod( operationName="upload" )

...

public String upload(@WebParam( name="destination" ) UploadDestination dest) {

 // Get the JBI context
 JBIContext jbiContext = JBIContextManager.getJBIContext();
 Exchange exchange = jbiContext.getExchange();

 try {
 Set<DataHandler> atts = exchange.getInMessageAttachments();
 int n = 0;
 for(DataHandler att : atts) {
 if(n == 1) { // Ignore 1st attachment (bug workaround... may be useless with latest release ?)
 FileOutputStream out = new FileOutputStream(dest.getPath() + File.separator + dest.getName());
 InputStream in = att.getInputStream();
 byte buf[] = new byte[256];
 while(in.read(buf) >= 0) {
 out.write(buf);
 }
 out.close();
 }
 n++;
 }
 } catch (Exception e) {
 Logger.getLogger( getClass().getName()).severe("Upload error: " + e.getMessage());
 }

 return "upload destination=" + dest;
 }
{code}

h2. Class for complex type parameter

This class is a simple JavaBean (POJO with getter/setter methods for each field: here, fields are "path" and "name", as the class represents an "upload destination" = a file).

{code}
package org.ow2.petals.usecase.jsr181;

public class UploadDestination {
 String name_ = "/tmp";
 String path_ = "petals-attachment";

 public String getName() {
 return name_;
 }
 public void setName(String name) {
 this.name_ = name;
 }
 public String getPath() {
 return path_;
 }
 public void setPath(String path) {
 this.path_ = path;
 }

 public String toString() { return (path_ == null ? "" : path_) + "/" + name_; }
}
{code}

h1. Invoking a Petals service

This class illustrates how a JSR-181 implementation can invoke a Petals service.
The invoked service is here a mailing service.

{code}
package org.ow2.sample;

import java.util.logging.Logger;

import javax.jbi.messaging.MessagingException;
import javax.jws.Oneway;
import javax.jws.WebMethod;
import javax.jws.WebParam;
import javax.jws.WebResult;
import javax.jws.WebService;
import javax.xml.namespace.QName;

import org.ow2.petals.component.framework.api.Message.MEPConstants;
import org.ow2.petals.component.framework.api.exception.PEtALSCDKException;
import org.ow2.petals.component.framework.api.message.Exchange;
import org.ow2.petals.jsr181.JBIContext;
import org.ow2.petals.jsr181.JBIContextManager;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

import com.ebmwebsourcing.easycommons.xml.DocumentBuilders;

/**
* Here is a sample JAX-WS implementation.

* 
* For more information about JAX-WS, please visit
* https://jax-ws.dev.java.net/jax-ws-ea3/docs/annotations.html.
*

*/
@WebService( serviceName="MailProxyService", targetNamespace="http://sample.ow2.org", portName="MailProxyServicePort" )

...

public class MailProxyService {

/* (non-Javadoc)
* @see JaxWSInterface#HelloWorld()
*/
@WebMethod( operationName="helloWorld" )
@WebResult( name="returnMessage" )
public String helloWorld() {
return "Hello World!";
}

/*
* (non-Javadoc)
* @see toto.JaxWSInterface
* #propagateMessage(java.lang.String)
*/
@WebMethod( operationName="listenToTheWorld" )
@Oneway
public void propagateMessage( @WebParam( name="message" ) String message ) {

// We here illustrate a method that does not return anything.
// This method uses a Petals extension to invoke other services in the bus.

// Get the JBI context
JBIContext jbiContext = JBIContextManager.getJBIContext();

// Create the mail content
StringBuilder mailContent = new StringBuilder();
mailContent.append( "Propagating the received message...\n" ).append( message );

// Create a XML document...
final String MAIL_NS = "http://petals.ow2.org/components/mail/version-3";

Document mailDocument = DocumentBuilders.newDocument();
final Element mailElement = mailDocument.createElementNS( MAIL_NS, "mail" );
mailDocument.appendChild( mailElement );

final Element bodyElement = mailDocument.createElementNS( MAIL_NS, "body" );
mailElement.appendChild( bodyElement );
bodyElement.setTextContent( mailContent.toString());

// ... and send it to a mailing service.
try {
final Exchange mailExchange = jbiContext.getMessageSender().createExchange( MEPConstants.IN_ONLY_PATTERN );
mailExchange.setInterfaceName( new QName( "http://petals.ow2.org/components/mail/version-3", "Mail" ));
mailExchange.setService( new QName( "http://petals.ow2.org/components/mail/version-3", "ReportMailService" ));
mailExchange.setOperation(new QName("http://petals.ow2.org/components/mail/version-3", "SendMail"));
mailExchange.setInMessageContent( mailDocument );

// Synchronous invocation
jbiContext.getMessageSender().send( mailExchange );

} catch( MessagingException e ) {
Logger.getLogger( getClass().getName()).severe( "Failed to send a message to the Petals Mail component. Messaging error." );

} catch( PEtALSCDKException e ) {
Logger.getLogger( getClass().getName()).severe( "Failed to send a message to the Petals Mail component. Petals CDK error." );
}
}
}
{code}

Wiki

All versions of Petals ESB

Helpful links

Use Cases for Petals-SE-JSR181

Changes (8)