The purpose of the Pentaho Design Studio is to facilitate the creation and management of files within your Pentaho solutions. The Design Studio helps organize these files and provides editors for each type of file. There are several levels of organization within the Design Studio: workspaces, project, views, editors, and perspectives. If you haven't done so already start up the design studio and take a look at the basic layout.
A workspace is a directory that contains a collection of projects, along with preferences and other settings related to the projects it contains. When working in the Design Studio keep in mind you are working with a single workspace. If you would like to change the workspace currently being used by the Design Studio simply select the Set Workspace option from the File menu. The Design Studio comes with a preexisting workspace containing a single project called Default Project.
Projects, Folders and Files
There are three different types of resources in the Design Studio: projects, folders, and files. Projects are the largest structural unit used by the Design Studio. Projects contain folders and files, and they can be opened, closed, or built. Folders can contain other folders and files. The Design Studio provides a number of mechanisms for working with projects, folders and files. A Pentaho BI solution is typically represented as a project of the Design Studio. The folders and file represent the hierarchy of content within solutions. As mentioned earlier, the design studio comes preconfigured with a workspace that contains a single project name "Default Project". If you expand the project in the left hand tree you'll notice that the project contains a single file named "untitled.xaction".
A view is a visual component within the Design Studio. It is typically used to navigate a hierarchy of information (such as the resources in the Design Studio), open an editor, or display properties for the active editor. Modifications made in a view are saved immediately. Normally, only one instance of a particular type of view may exist within a Design Studio window. The "Package Explorer" displayed in the left hand side of the Design Studio is an example of a view. It allows you to navigate the folders and files located within a project.
An editor is also a visual component within the Design Studio. It is typically used to edit or browse a resource. Modifications made in an editor follow an open-save-close lifecycle model. Multiple instances of an editor type may exist within a Design Studio window. The Action Sequence Editor is one example of an editor. To see the Action Sequence Editor in action expand the "Default Project" in the Package Explorer view and double-click on untitled.xaction. The action sequence editor should appear.
A perspective is a group of views and editors in the Design Studio window. One or more perspectives can exist in a single Design Studio window. Each perspective contains one or more views and editors. Within a window, each perspective may have a different set of views but all perspectives share the same set of editors. You can think of a perspective is a visual organization of the windows within a workspace. The default Design Studio configuration contains a single Perspective name "Pentaho". Note that the active perspective is displayed in the upper right hand corner of the Design Studio. The Pentaho perspective is a very simple perspective containing the Package Explorer view and an area reserved for the editor.
Action Sequence Editor
Activities that the Pentaho BI platform performs are defined by Action Sequence XML documents. Action Sequences define activities such as database queries, report generation, email actions and the order in which they occur. Data can be passed between Actions within an Action Sequence or between executions of other Action Sequences. They define the inputs that must be available prior to execution, the processes that will be performed and the outputs that will be available to other Action Sequences after execution is complete.
The Pentaho Action Sequence Editor is an Eclipse plugin which allows the user to create and edit action sequences within their Pentaho solutions. From within the Design studio let's quickly create a new action sequence and take a look at how it appears within the editor. Select the Default Project within the Package Explorer view on the left side of the Design Studio. From the toolbar at the top of the Design Studio select "New Action Sequence" from the Pentaho Toolbar Item. The Action Sequence Wizard should appear. From the Template pulldown select Sample Burst Action then select Finish. A new action sequence editor should open displaying the contents of the action sequence we just created. Now let's take a look at the various parts of the action sequence editor.
As the name implies, the General tab is where the general information about the action sequence is managed. Stuff like the title, description, and icon that will appear for this action sequence when browsing your solution. Additionally you can indicate the logging level you would like to use for this action sequence. Logged messages will appear in the pentaho-bi-suite/jboss/server/default/log/server.log file. If you're having problems getting your action sequences working, the log file is a good place to look for clues as to what the problem might be.
Define Process Tab
Notice there three sections labeled "Process Inputs", "Process Actions" and "Process Outputs." Let's take a closer look at each.
The Process Inputs section represents the "contract" this action sequence this with the outside world regarding information that will be needed for this action sequence to run. Inputs can come from the request (URL in most cases), the session or runtime. Resources are the files needed by the action sequence to complete its job. For example, if an action sequence is going to run a JFree report (which this one does), one of the resources would be the location of the JFree report definition file.