Tuesday, June 26, 2012

Default transition UI - Part 02

WSO2 Governance Registry lifecycle model has many extension points. One of them is called the transition UI. In one of my previous posts, I have given an insight to what transition UIs are. This post is an continuation of my previous post.

WSO2 G-Reg distribution includes a single transition UI. This transition UI is used by the default service lifecycle for its service version functionality(more information can be found here). This transition UI does the following.

The name of the default transition UI is "pre_invoke_ajaxprocessor.jsp".

The main functionality of this UI is to take user input for the versions of services and their dependent resources, so that they can be passed to the service version executor.

It is displayed only for services. It will ignore all other media types.

It will list down all the dependencies of a service resource. These dependencies are gathered recursively. Hence all the dependencies of that service and its dependent resources, will be displayed in the UI.

Parameters can be passed to these UIs. The lifecycle configuration model supports adding parameters to a transition UI element and these parameters are added as URL parameters. Please note the section after the "?" in the following example.

The "pre_invoke_ajaxprocessor.jsp" accepts 5 different parameters and all of these are optional.

  1. preserveOriginal - Setting this parameter will allow users to instruct the server to keep the old resource or whether to delete it. If this parameter is set to "false", then the underlying implementation will delete the resource after a state transition. This parameter is set to "true" by default.
  2. viewVersion - This parameter is there to instruct the jsp page to avoid displaying the content of the page. If the viewVersions is set to "false", the underlying implementation of the jsp page will do an invokeAspct() call including parameters like "preserveOriginal". We use this parameter to pass the value of the "preserveOriginal" parameter to the server without displaying any additional UI to the user.
  3. displayMediaType - This parameter is used to override the default media type which is checked by the jsp page. By default, this UI checks whether the resource has a media type equal to "application/vnd.wso2-service+xml"(which is the default service media type of WSO2 G-Reg). By setting this parameter, users can override the above mentioned value. 
  4. showDependencies - Instructs the jsp page to not to show the dependent resources of the service. If this parameter is set to "false", the jsp file will only show an input field for the service resource in the custom UI(it will not give input fields for any dependent resources).
  5. currentEnvironment - Defines what is the current environment of the service(or its dependencies). The value of this parameter should be a path in the registry. If this parameter is set, the jsp page will not show input fields for resources that are not in the given registry path. 

No comments:

Post a Comment