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h1. Summary

This tutorial explains how you can invoke a Petals service when a file is added in a directory.
Such a service will either send the dropped file as an attachment to the invoked service, or load it and send its content in the message body.

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Technically, this tutorial shows the creation of a service-unit for the [Petals-BC-FileTransfer|petalscomponents:Petals-BC-Filetransfer] component in *consumes* mode.

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*Level:* Easy
*Estimated time:* 10 minutes the first time, 4 minutes then
*Expected skills:* know the basics about WSDL and XML
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h1. Creating the Service-Unit project

h2. Getting started

Start Petals Studio.
In the menu, select *File > New > Service-Unit Project*.
If you do not see it, go into *File > New > Other...* Then, select *Service-Unit Project* under the *Petals* category.

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A wizard opens up, showing three drop-down lists.
In the *Use Case* list, select *Consume or Call a Petals service*.
In the *Petals Component* list, select *File Transfer // petals-bc-filetransfer*.
In the *Component Version* list, select the version of the Petals-BC-FileTransfer that you are using in Petals.

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In the scope of this tutorial, we are going to work with the version 2.4 of the File Transfer component.
Which gives us:

!petals-studio-tuto-consumes-ft-1.jpg!

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Click *Next*.


h2. Identifying the target service

The current page requires you to fill-in the base information to put in the JBI descriptor (*META-INF/jbi.xml*).
In particular, it defines the interface, service and end-point names of the service that will be invoked when a file is added in the watched directory.

!petals-studio-tuto-consumes-ft-2.jpg!

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A service is identified by a triplet, interface, service and end-point names. This triplet is unique in a Petals topology.
When you consume a service, the service is selected in a set. This set is defined by the invocation properties.

If the 3 fields are set in the consume properties, then the set will contain at most 1 result (there can be only 1 service with this ID).
If 2 fields are set, then the third one is considered as a wildcard and the set will larger.

Consume possibilities are the following ones:
* By interface, service and end-point names.
* By interface and service names.
* By interface name only.
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You can obviously fill-in these fields by hand.
However, the most efficient way is to use the [Petals Services explorer|Getting familiar with the Petals Services view] (provided it was populated).
Click *Select a service*. A selection dialog shows up, providing filtering assistance.

!petals-studio-tuto-consumes-ft-2bis.jpg!

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When you have selected your service, click *OK*.
The wizard fields are filled-in automatically.

!petals-studio-tuto-consumes-ft-3.jpg!

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{note}
The values for the interface, service and end-point names must match the values defined in the jbi.xml of the invoked service.
Indeed, this service must be a Petals service, and thus be described in a jbi.xml.
As a reminder, the jbi.xml values and the WSDL values (if the WSDL exists) of the invoked service must be exactly the same.

For this reason, filling-in the information by hand or modifying it is discouraged.
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Click *Next*.


h2. Defining the project name

This page defines the name and the location of the project that will be created.
Indeed, this wizard will result in the creation of a project containing all the required elements for a File Transfer service-unit.

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Enter a project name for your project.
If you do not want your project to be created in the default workspace, uncheck *Use default location*.
Then click *Browse...* and select the location where the project will be created.

!petals-studio-tuto-consumes-ft-4.jpg!

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{note}
Petals service-units have a naming convention.
For a service-unit which consumes (calls) a service, the convention is *su\-*_<Protocol or Technology>_*\-*_<Service name>_*\-consume*
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Then, click *Next*.


h2. Specifying the File Transfer parameters

This page defines information which are specific to the Petals File Transfer component.
There are three parameters to take care of here:
* There is the *directory* that will be polled regularly.
* There is the *name pattern* of the file that must be sent to the invoked service.
* And there is the *polling period*, i.e. the time interval between each polling of the read directory.

The other displayed parameters are optional.
The meaning of all the parameters can be read in the documentation of the [Petals-BC-FileTransfer|petalscomponents:Petals-BC-Filetransfer] component.

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Click *Next*.


h2. Specifying the CDK parameters

The CDK is the Petals framework to develop JBI components.
The Petals-BC-FileTransfer component was developed with this framework.

This page requires information related to the CDK.
If the service to consume is described by a WSDL, then there is a list of the possible operations that can be invoked.
Otherwise, you have three parameters to complete here (others are optional or have default values):
* The name space of the invoked operation's name (WSDL operations are QNames).
* The local part of the invoked operation's name (WSDL operations are QNames).
* The Message Exchange Pattern (MEP).

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With this component, only operations that work with the *InOnly* MEP can invoked.
The wizard only shows these operations.

The meaning of all the CDK parameters for File Transfer can be found in the documentation of the [Petals-BC-FileTransfer|petalscomponents:Petals-BC-Filetransfer] component.

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Click *Finish* to complete the wizard.


h2. Checking the result

When the wizard has completed, a new project has been created and is visible in your workspace.

It contains a jbi.xml file, located under *src/main/jbi*.
This hierarchy allows you to work with Apache Maven then (a pom.xml was also created at the root of the project).
There is nothing else in the project.

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h1. Updating, packaging and deploying

h2. Further edition and packaging

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The created project being a [Service-Unit project|Working with Service Unit projects], you can [package it as any Service-Unit project|Working with Service Unit projects#Export for Petals].
It results in the creation of a Service Assembly for the Petals-BC-FileTransfer component. Its location depends on your export choices.

h2. Deployment

The deployment of the created service assembly can be achieved with the Petals web console.
Or you can do it by dropping the service assembly in the *install* directory of your Petals installation.
This second option should only be used in development steps.

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First, make sure the Petals-BC-FileTransfer is installed in your Petals environment.
Then, install the service assembly in your Petals, using one of the two ways indicated above.

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There is no need to update configuration of the File Transfer component to make it work.
Using the default settings is enough to make the service-unit work.