Introduction to Talend Custom component development and implementation principles

Talend Open Studio (TOS) has a custom component development module that may not appear in the default view and needs to be opened in Windows-perspective-component Designer.

First entry into the component development interface is not possible to create a new component project or open component, you need to set up in the TOS first:

1. Modify the User component folder in the Windows-preferences-talend-components to specify the address where the custom component is stored. Components in this folder are automatically loaded into palette after you restart the TOS.

2. Modify the Component project address in Windows-preferences-talend Component designer and specify a folder as the working directory for the development Component.

After the setup is complete, the Talend component can be developed.

Talend components typically contain three parts, Begin,main and end. The begin section is typically used to initialize the contents of the control, and the main part is the implementation and looping of the internal logic, and the end part is the logic of closing the loop and making the final end. After you create a new component component, you can select how many parts of the component you have in the graphical interface, choose the icon for the component, add a jar package to the component, and so on. The final step is to set up the configuration XML for this component, including the declaration of the component, which type of control is included in the folder, which types of connections you can use, which parameters to include, the return value, and so on.

In addition to the ability to create new components, you can also open the TOS from the Component development interface: Right-click on the Component Development project, click Copy Component from Palette, select the components that need to be opened. This method will copy the system's own components into the folder of our custom components, refer to these self-contained components can help us to develop without understanding the development of talend components, such as the XML settings in the component, the content of each part of the writing.

The main use of Talend component development is Java Jet technology. One obvious feature of Java jet is that the <% and%> are included in the Jet engine Processing section, which can be either a variable or a value read from the XML, or a logical judgment, with the generated code outside the angle brackets. This is how the Java code is formed by the combination of the various modules.

When we do talend job development, we actually develop an XML file that contains the Talend components we need to use and the variables and parameters in the components. The process of compiling the talend is to read the contents of the variables and elements from the job's XML, generate Java code from the jet engine, and then generate the jar package from the Java code.

Introduction to Talend Custom component development and implementation principles