How do I program message flows?
New users: Use the links in this topic to get information about the concepts and tasks associated with programming message flows.
This topic contains the following sections:
How do I transform data graphically?
In WebSphere® Message
Broker Version 8.0 and later, message
maps are graphical data maps. Graphical data maps use a drag-and-drop
interface to create and transform messages. You can use conditional
logic, ESQL functions, and XPath functions to create complex mappings
and transformations. You can also use message mapping to select and
manipulate data in database tables. You must create a message
definition for any messages that you include in a graphical data
map. Graphical data map files are stored in integration
projects.
- How do I create a graphical
data map file?
Follow this link for instructions on how to create a graphical data map in the Integration Development perspective. You can also create a graphical data map from the Mapping node; see Creating a message map from a Mapping node.
- What does the Graphical
Data Mapping editor look like?
You create and modify mappings in the Graphical Data Mapping editor. Use this link to discover information about the Graphical Data Mapping editor.
- How do I
configure a graphical data map?
When you configure graphical data mappings, you can drag content from a source to a target. The source can be a message, a database, or both, and the target can be messages, database tables, or both. If your target is a database, you can select the database operation (for example: insert, update, or delete) that you want to perform on the table. You can set the value for your target to be a constant, or you can use a function or expression to produce the value. Additionally, you can configure conditional mappings to set different values for targets that are based on the content of the sources, and to handle repeating elements in sources and targets. Follow this link to discover more about graphical data mappings.
- Graphical data mapping syntax:
When you use an expression to set the value of a target in a message map, the expression must be in XPath format.
- What syntax is used in Mapping nodes?
Use this link to discover more about the XPath syntax that is used in message maps.
- Which functions
can I use in my graphical data maps?
Use this link to discover more about the type of functions that you can use in your graphical data maps.
- How can I find out more about XPath
query syntax?
To discover more about XPath, follow this link to the W3C recommended XPath 1.0 query syntax reference document. This link works only if you have an active internet connection.
- What syntax is used in Mapping nodes?
How do I use ESQL?
Extended Structured Query Language (ESQL) is a programming language that is based on Structured Query Language (SQL), which is commonly used with relational databases such as IBM® DB2®. ESQL extends the constructs of the SQL language to provide support for you to work with both message and database content. ESQL can be used with the Compute, Database, and Filter nodes.
Use the following links to discover how to use ESQL in your message
flows:
- How do I create an ESQL file?
The ESQL code for each of your nodes is contained within a module in an ESQL file. Use this topic to discover how to create an empty ESQL file in your integration project. Alternatively, you can select Open ESQL to create an ESQL file when you configure the first node in a message flow that uses ESQL. This action creates an ESQL file with skeleton ESQL code for a module that is associated with the selected node. You can also select an ESQL module for a node from a different integration project by creating a project reference; see Referencing resources in other libraries.
- What is the ESQL editor?
You can create and modify your ESQL code in the ESQL editor. You can change the way that code is displayed in the ESQL editor, and modify how the ESQL editor validates code, by changing your ESQL preferences.
- How do I create ESQL for a node?
Follow this link to get an overview of how to create ESQL for your node, including more information about the differences between the skeleton ESQL code that is generated for the modules that are associated with the Compute, Database, and Filter nodes.
- How do I modify ESQL for a node?
Follow this link to discover how to modify the skeleton ESQL module code.
- How do I save an ESQL file?
Discover how to save your ESQL file.
- How do I write ESQL code?
Follow this link to get introductory information about writing ESQL code for your message flows. Discover how to manipulate the message tree, transform data, access databases, and work with messages from different message domains using ESQL.
- ESQL language:
Use the following the links to get concept and reference information about the ESQL language:
- ESQL data types overview
- ESQL variables overview
- ESQL operators overview
- ESQL field references overview
- ESQL statements overview
- ESQL functions overview
- ESQL procedures overview
- Special characters, case sensitivity, and comments in ESQL
- ESQL modules overview
- ESQL reserved keywords
- ESQL non-reserved keywords
How do I use Java?
You can create a Java™ class file for a JavaCompute node and code Java functions to tailor the behavior of the node. You can add any valid Java code to your JavaCompute nodes and use the Java user-defined node API to process messages. You manage Java files through the Java perspective.
- How do I use a JavaCompute node?
You can use the JavaCompute node to examine the content of an input message, transform a message, and build new messages. Follow this link to discover how to use and configure the JavaCompute node in your message flows.
- How do I create Java code for a JavaCompute node?
Discover how to create a Java class file using the JavaCompute node wizard. The JavaCompute node wizard creates a Java class with skeleton Java code that is based on the options that you select in the wizard. You can then modify the skeleton code to perform your own processing.
- How do I open an existing Java file?
You can modify existing Java code that you have created in a Java Project.
- How do I save a Java file?
Discover how to save your Java file.
- How do I write Java for message flows?
Get introductory information about writing Java code for your message flows, including how to manipulate the message tree, access databases, handle errors, and access integration node properties.
- Java Development User Guide - Views and Editors
Get a list of concept, task, and reference topics that relate to editors and views for working with Java. This link works only if you are accessing this documentation from the IBM Integration Toolkit.
- Java Development User Guide - Java Content Assist
You can use code assist to provide a list of available command completions that you can select to insert into the editor. You can also use command assist to access Javadoc information about code in the Java editor. This link works only if you are accessing this documentation from the IBM Integration Toolkit.
- How do I add Java code dependencies?
Discover how to include references to other Java projects and JAR files in your JavaCompute node code.
- Where can I find
the Java user-defined node API?
Follow this link to the Java API for the IBM Integration Bus classes for creating a Java user-defined node, which you can also use to code your JavaCompute node.
How do I use XML transformations?
You can use the XSLTransform node
to transform an XML message into another form of XML according to
the rules provided by an XSL (Extensible Stylesheet Language) style
sheet. You can specify the location of the style sheet to apply to
this transformation in three ways:
- By using the content of the XML data within the message itself, which transforms the message according to a style sheet that the message itself defines.
- By setting a value within the LocalEnvironment folder.
- By using node properties, which ensures that the transformation that is defined by this single style sheet is applied to every message that is processed by this node.
You can discover links to information about using XML transformation
in this section.
- How do I use the XSLTransform node?
Follow this link to discover how to use and configure the XSLTransform node to transform an XML message into another form of XML.
- Where can I find out more about XSL Transformations?
To discover more about XML Transformations, follow this link to the W3C specification of the syntax and semantics of the XSL Transformations language for transforming XML documents into other XML documents.
How do I use .NET?
On Windows, use .NET assemblies to create, modify, and route messages. You can call .NET assemblies from a .NETCompute node. Using ESQL, you can also call assemblies from a Compute node. For a high-level overview about what you can do with .NET, see Using .NET.
How do I use XPath?
The XML Path Language (XPath) is a language that is used to uniquely
identify or address parts of an XML document. An XPath expression
can be used to search through an XML document, and extract information
from the nodes (any part of the document, such as an element or attribute)
in it. XPath expressions can be used in message maps, and in the properties
of some of the nodes. Typically, you might use XPath when you are
using Java, XML, or PHP.
- Where can I get an overview of XPath?
Follow this link for an overview of XPath, and how you can use XPath with nodes.
- How do I use the XPath Expression Builder?
You can use the XPath Expression Builder to add XPath expressions to your node properties. Follow this link for information about how to use the XPath Expression Builder.