The technical layer is responsible for communication with the neighbor systems. This comprises modules for receiving and sending data.

The next sections cope with the different data sources. For each technical protocol the available receiver and sender modules are described. A table indicates whether the modules:

• process message in a text- or object-oriented mannner
• support transaction handling (key Transaction),
• can handle responses (key Response), cf. Communication Modes
• and for receiver the way they can be started.

A PDF-file is available as a reference, which technical modules can be used with which message modules.

The File modules treat all interfaces to neighbor systems which are available as files on local or mounted file systems.

All FileXXXReceivers are available in two flavours:

• The FileXXXReceiver to receive data from files and terminate afterwards (see Starting with Shell Script).
• The FileXXXReceiverThread to continously waiting for files (see Running as a Background Service resp. Running inside a Servlet Engine).

FileReceiver(Thread)

The FileReceiver reads the content of files into a string.

FileSender

The FileSender writes a string to a file.

FileLineReaderReceiver(Thread)

The FileLineReaderReceiver opens a Reader object for the input file and sends a reference to it through the xBus. This is useful for transferring large documents and be able to change the encoding.

FileLineWriterSender

The FileLineWriterSender receives a Reader object and copies its data record by record (line by line) to the destination file. It is able to change the character encoding if necessary.

FileStreamReceiver(Thread)

The FileStreamReceiver opens an InputStream object for the input file and sends a reference to it through the xBus. This is useful for transferring large documents without changes of the encoding.

FileStreamSender

The FileStreamSender receives an InputStream object and copies its data byte by byte to the destination file. It is not able to change the character encoding.

FileByteArrayListReceiver(Thread)

The FileByteArrayListReceiver behaves pretty much like the FileReceiver, but it reads the data into a list of byte arrays instead of a string. For more details see the ByteArrayListMessage.

FileByteArrayListSender

The FileByteArrayListSender behaves pretty much like the FileSender, but it stores the data into lists of byte array instead of strings. For more details see the ByteArrayListMessage.

All File modules implement a transaction logic by writing temporary files and special actions during commit or rollback.

System	Type	Transaction	Response	Starting
FileReceiver	Text	yes	no	shell script
FileReceiverThread	Text	yes	no	background service, servlet engine
FileSender	Text	yes	no	-
FileLineReaderReceiver	Object	yes	no	shell script
FileLineReaderReceiverThread	Object	yes	no	background service, servlet engine
FileLineWriterSender	Object	yes	no	-
FileStreamReceiver	Object	yes	no	shell script
FileStreamReceiverThread	Object	yes	no	background service, servlet engine
FileStreamSender	Object	yes	no	-
FileByteArrayListReceiver	Object	yes	no	shell script
FileByteArrayListReceiverThread	Object	yes	no	background service, servlet engine
FileByteArrayListSender	Object	yes	no	-

HTTP is the abbreviation for hypertext transfer protocol. It is a standard protocol for sending data through the internet. While with HTTP all data is sent as clear text, using HTTPS the data is encrypted. All HTTPxxxReceivers and HTTPxxxSenders support both protocols.

HTTPReceiver

The HTTPReceiver receives a request via a HTTP connection. It is implemented as a Java-Servlet. This means, a servlet-engine like Tomcat is needed for running the HTTPReveiver.

HTTPSender

The HTTPSender sends a message via HTTP to an URL.

HTTPStreamReceiver

The HTTPStreamReceiver opens an InputStream object for the request received via a HTTP connection and sends a reference to it through the xBus. This is useful for transferring large documents without changes of the encoding.

HTTPStreamSender

The HTTPStreamSender receives an InputStream object and copies its data byte by byte to the destination URL. It is not able to change the character encoding.

HTTPParameterReceiver

The HTTPStreamReceiver reads the request data out of the parameters of the URL. They are transformed into a XML document (described here) for further processing. The response of the processing must be an arbitrary XML document (or null), which will be given back to the caller.

HTTPParameterSender

The HTTPStreamSender gets a XML document (described here) and transforms the data into the parameters of an URL, where it will be sent to. The response must be an arbitrary XML document (or null).

HTTPByteArrayListSender

The HTTPByteArrayListSender converts a ByteArrayList into a String and sends it to the destination URL.

System	Type	Transaction	Response	Starting
HTTPReceiver	Text	no	yes	servlet engine
HTTPSender	Text	no	yes	-
HTTPStreamReceiver	Object	no	no	servlet engine
HTTPParameterSender	Object	no	yes	-
HTTPParameterReceiver	Object	no	yes	servlet engine
HTTPStreamSender	Object	no	no	-
HTTPByteArrayListSender	Object	no	no	-

FTP is the abbreviation for file transfer protocol. It is a standard protocol to access files through an IP connection.

FTPReceiver

The FTPReceiver receives a request by reading a file from a FTP server.

FTPSender

The FTPSender sends a message by writing it into a file on a FTP server.

Both modules implement a transaction logic by writing temporary files and special actions during commit or rollback.

System	Type	Transaction	Response	Starting
FTPReceiver	Text	yes	no	shell script
FTPSender	Text	yes	no	-

All message queues servers which implement Java's JMS 1.0.2 API can be accessed by the xBus.

MQReceiverThread

The MQReceiver receives messages from message queues.

MQSender

The MQSender sends a message to a message queue.

System	Type	Transaction	Response	Starting
MQReceiverThread	Text	yes	no	background service, servlet engine
MQSender	Text	yes	no	-

All databases with an existing JDBC driver can be accessed by the xBus.

DatabaseSender

The DatabaseSender sends SQL statements to a database connection and returns the result. Request and response are XML messages, with a special format described here.

System	Type	Transaction	Response	Starting
DatabaseSender	Object	yes	yes	-

Directory information can be retrieved from LDAP servers.

LDAPSender

The LDAPSender sends queries to a LDAP server and returns the result. Currently search queries with attributes or filters as specified in RFC 2254 are possible. Request and response are XML messages, with a special format described here.

System	Type	Transaction	Response	Starting
LDAPSender	Object	no	yes	-

JavaReceiver

The JavaReceiver can be used to send a message to the xBus by calling it directly from another java application.

The class
net.sf.xbus.bootstrap.JavaReceiverBootstrap
provides the method
public Object receive(String system, Object request) throws XException

Calling this method by a Java application will process the given request for the given system and return the result according to the configuration of the xBus.

JavaSender

The JavaSender sends data by calling a method of a class. Both class and method are read out of the configuration. The method must have this signature:

• public Object methodname(Object callData)

PingSender

The PingSender is not a real sender. It responds exactly the data of the request. This can be used to integrate it in the routing chain to achieve only a transformation or for testing purposes.

System	Type	Transaction	Response	Starting
JavaReceiver	Object	no	yes	java application
JavaSender	Object	no	yes	-
PingSender	Object	no	yes	-

Another way of receiving and sending messages is via email.

POP3Receiver(Thread)

POP3 is the standard protocol for receiving emails. The POP3Receiver reads the first message from the INBOX of a configured POP3 account. The POP3ReceiverThread continuously waits for messages and processes them.

After successful processing, the message is deleted on the server.

POP3XMLReceiver(Thread)

While the POP3Receiver(Thread) retrieves only the body of the message, the POP3XMLReceiver(Thread) delivers more information like the sender or the subject of the message by packing all data into a XML document (described here).

SMTPSender

SMTP is the standard protocol for sending emails. The SMTPSender sends out a message to email addresses. To do this, a SMTP server must be available.

System	Type	Transaction	Response	Starting
POP3Receiver	Text	yes	no	shell script
POP3ReceiverThread	Text	yes	no	background service, servlet engine
POP3XMLReceiver	XML	yes	no	shell script
POP3XMLReceiverThread	XML	yes	no	background service, servlet engine
SMTPSender	Text	no	no	-

TCP/IP sockets are a very rudimentary way for sending messages.

SocketSender

Sending messages via a TCP/IP socket.

System	Type	Transaction	Response	Starting
SocketSender	Text	no	no	-

The AS/400 is a hardware platform of IBM, nowadays also called iSeries. There are two ways of accessing an AS/400 by the xBus:

• Reading and writing files in the QSYS.LIB file system. Each file in this file system has a description that describes the file characteristics and how the data associated with the file is organized into records, and, in many cases, the fields in the records.
• Calling RPG programs.

The xBus accesses these resources remotely via a TCP/IP connection. How the connection to the AS/400 is build up and which requirements must be fulfilled is explained here.

AS400FileReceiver

The AS400FileReceiver reads the content of files on the AS/400 into strings.

AS400FileSender

The AS400FileSender writes a string to a file on the AS/400.

AS400LineReaderReceiver

The AS400LineReaderReceiver opens a Reader object for the input file and sends a reference to it through the xBus. This is useful for transferring large documents and be able to change the encoding.

AS400ByteArrayListReceiver

The AS400ByteArrayListReceiver behaves pretty much like the AS400FileReceiver, but it reads the data into lists of byte array instead of strings. For more details see the ByteArrayListMessage.

AS400ByteArrayListSender

The AS400ByteArrayListSender writes a byte array list to a file on the AS/400. For more details see the ByteArrayListMessage.

AS400ProgramSender

The AS400ProgramSender calls a program on the AS/400. The input parameters for the program are converted from a special XML format and the output parameters will also be converted back into a special XML format. For more information see Calling programs on the AS/400.

All AS400xxxReceiver modules implement a transaction logic with special actions during commit.

System	Type	Transaction	Response	Starting
AS400FileReceiver	Text	yes	no	shell script
AS400FileSender	Text	no	no	-
AS400LineReaderReceiver	Object	yes	no	shell script
AS400ByteArrayListReceiver	Object	yes	no	shell script
AS400ByteArrayListSender	Object	no	no	-
AS400ProgramSender	Object	no	yes	-