Jakarta Activation

Within computing, Jakarta Activation (JAF; formerly JavaBeans Activation Framework) is a Jakarta EE API that enables developers to:JavaBeans Activation Framework
Retrieved 2020-03-30.
* determine the type of an arbitrary piece of data,
* encapsulate access to it,
* discover the operations available on it and
* to instantiate the appropriate bean to perform the operation(s).

It also enables developers to dynamically register types of arbitrary data and actions associated with particular kinds of data. Additionally, it enables a program to dynamically provide or retrieve JavaBeans that implement actions associated with some kind of data. Originally an extension API, it was available as a standard API in Java SE (from Java SE 6 on) and Java EE, but was removed in Java SE 11.

DataSource Interface

* Provides access to an arbitrary collection of data
* Get name of the data, data-type name (content type), and the data itself as Input Stream or Output Stream
* Two implementation classes provided
** URLDataSource simplifies the handling of data described by URLs
** FileDataSource simple DataSource object that encapsulates a file provides data typing services -> delegated to a FileTypeMap object.
* Other implementations
** ''javax.mail.internet.MimePartDataSource''
** ''javax.mail.util.ByteArrayDataSource''

DataContentHandler interface

* Convert the object to a byte stream and write it to the output stream
* Convert streams in to objects
* Used to get object/data which can be transferred
* Uses java.awt.datatransfer.DataFlavor to indicate the data that can be accessed. ''DataFlavor is a data format as would appear on a clipboard, during drag and drop, or in a file system.''

CommandMap class

* An abstract class provides an interface to a registry of command objects available in the system
* Developer develop their own implementation or use
** MailcapCommandMap class that implements a CommandMap whose configuration is based on mailcap files
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* Command list available from a MIME Type is stored in CommandInfo object.

CommandObject interface

* Interface to be implemented by JavaBeans components that are ActivationFramework aware
* Simple interface with one method:
** ''setCommandContext(String verb, DataHandler dh)''

Example: Compose an e-mail with attachment

import javax.activation.DataHandler;
import javax.activation.FileDataSource;
import javax.mail.internet.*;
import javax.mail.*;

...

// Create a message.
MimeMessage message = new MimeMessage(session);

...

// Create the Multipart to be added the parts to
Multipart multipart= new MimeMultipart();

// Create and fill the first text message part
MimeBodyPart mbp = new MimeBodyPart();
mbp.setText("Body");
multipart.addBodyPart(mbp);

// Create a file attachment and fill as second message part
mbp = new MimeBodyPart();
FileDataSource fds = new FileDataSource("C:\\attachment.zip");
mbp.setDataHandler(new DataHandler(fds));
mbp.setFileName(fds.getName());
multipart.addBodyPart(mbp);

// Add the multipart to the message
message.setContent(multipart);

...

References

External links

*

JSR 925: JavaBeans Activation Framework 1.2 Specification

Introduction to JavaBeans Activation Framework

Introductory presentation
*
* Example also available in ''Java 6 New Features: A Tutorial'' book, chapter-13

{{Jakarta EE

Java (programming language)