Petals Documentation > Petals ESB > Petals Components > Components Use Cases > Use Cases for Petals-SE-JSR181

Use Cases for Petals-SE-JSR181

This document is a complement to the documentation of the Petals SE-JSR181 component.
It assumes that you already know how to generate a JSR181 SU using PetalsStudio: most code examples detailed here are embedded in the JSR181 SU main class, pointed as <jsr181:class> in the jbi.xml of the SU.
Table of Contents

Implementing a web method that deals with complex types and attachments

Text File Extraction

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

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 {

	/**
	 * Extracts the content from the received attachment.
	 */
	@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.
	 * <p>
	 * Neither <i>in</i> nor <i>os</i> are closed by this method.<br />
	 * They must be explicitly closed after this method is called.
	 * </p>
	 *
	 * @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 );
		}
	}
}

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.

     @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;
     } 

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).

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_; }
}

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.

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.
 */
@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!";
	}

	/*
	 * Propagates a message as an email service invocation.
	 */
	@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." );
		}
	}
}
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