Controlling Execution of TIBCO BW services

• Process instances typically remain in memory as long as they are executing an activity. If the process instance is waiting for an incoming event (for example, a Wait for Adapter Message activity), the process instance can be paged out to disk and resumed later after the event arrives.
• New process instances are paged out to disk until there is available memory and resources to accommodate them.
• Use TIBCO admin to control execution of TIBCO BW process instances. Useful if system has limited resources & memory or to restrict process instances to run sequentially.

Go to --> Application Mgmt --> Application configuration --> click proccess service -> Advanced Tab

• Max Jobs : Specifies the maximum number of process instances that can concurrently be loaded into memory. Any process instances created once the maximum is reached must be paged out to disk.
• Activation Limit : Specifies that once a process instance is loaded, it must remain in memory until it completes. useful if you wish to specify sequential processing of incoming events, or if you want to enforce limited concurrent execution of process instances.
• Max Jobs (FLow Limit) : Specifies the maximum number of currently running process instance to start before suspending the process starter. Max Jobs (Flow Limit) field limits the number of process instances created by a process starter. This allows you to control the flow of processing so that incoming events are no longer accepted when the limit is reached. This is useful in protocols like TIBCO RVCM, JMS Durables TOpic, JMS Queue, Recceive Mail etc.

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Main Responsibilities of TIBCO Admin Server

1. Manage Storage for the domain -- Storage can be file based repository or in a database repository.
2. Enforce Security for the domain -- User authentication & authorization
3. Provide Load balancing -- each domain can be configured with one primary & multiple secondary servers. Primary server allows read & write operations while secondary servers only supports read operations.
4. Provide Failure recovery -- When primary server is down, secondary server continue serving.
   

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Elements of TIBCO Admin domain

1. Administration Server - Manages admin domain.Each administration server manages only one domain. Multiple secondary servers are allowed. Server can be accessed with web browser based TIBCO Administrator.
2. Machines - By default all machines in an admin domain are expected to be in same subnet. However TIBCO RVRD can be used to communicate to the machines on different subnet.
3. User & Acces Information - stored in domain repository. Also syncronize with LDAP server for users & groups
4. Runtime Application - Start, stop & monitor individual process engines & service instances.
5. TIBCO Hawk Agent -- Monitors local resources & conditions. Hawk Agent is an autonomous process & uses collection of locally loaded rules organized into rulebases to apply monitoring logic.

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Overview of TIBCO Administrator

Functions of TIBCO Administrator:

1. User Management -- creates users & roles, assign them access rights to TIBCO Admin console, application & application repository
2. Resource Management -- manage TIBCO software installed on other machines in domain & monitors machines in domain
3. Application Management -- upload, deploy & monitor applications

TIBCO Administrator Architecture includes:

• Tomcat web server -- manage basic communiaction & makes TIBCO Admin available
• Administrator Server -- Manage domain & application repositories
• User Management
• Resource Management
• Application Management

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Using Stylesheets in XML- CSS & XSLT

XML is a means of exchanging data between applications. It allows the developers to describe and structure their data in their own formats. As the XML gave more emphasis on data rather than formatting, the data in the XML document can be formatted in two ways:

• USING CSS
• USING XSL

Cascade Style Sheet( CSS):

Initially, Cascading Style sheets (CSS) were used for formatting the data in the XML documents. It allows the Web Developers to define a formatting for the elements in XML and the same can be applied to as many documents you like. The advantages are:

• It has a Precise control over presentation
• It is Resolution Independent
• It downloads Faster
• It is easy to maintain

Though it has a lot of advantages it also has following disadvantages.

• The order of elements for display cannot be changed
• An element cannot be processed more than once
• Generated text cannot be added to the presentation

Extensible Stylesheet Language (XSL):

The difficulties that were encountered with CSS were removed by making use of XSL. XSL is an application of XML It allows you to create high performance XML based systems by integrating Server side XML processing’s. The need for transforming data from one format to the other results in splitting XSL into two groups:

1. XSLT – It describes how to transform XML. Document into other formats.
2. XSL-FO- It describes formatting details of each element in the XML document.

XSLT:

The XML Style sheet Language Transformation (XSLT) is a mechanism of transforming one form of XML documents to the other form. It is a set of templates based on Xpath expressions that tells how to fetch a particular node from the XML documents. It is a part of XSL, which is a style sheet language for XML. XSLT is widely used in Websites Content Management to convert XML into HTML pages. It uses Xpath to define parts that match one or more templates. Xpath is an query language that allows you to identify the nodes. It can select nodes in any direction. An XSLT processor is used to perform transformations of XML document in to other formats based on the given XSLT document.

XSL_FO:

XSL-FO means Extensible Formatting Objects. There are two different ways in which the XML document can be formatted. They are:

• Layout Based formatting
• Content Based formatting

In a layout based formatting, the limitations of the target may constrain the content or appearance on the page, whereas in a Content Based Formatting, the target medium is generated to accommodate the information being formatted. The XSL FO allows you to make formatting and styling options to your document.

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Is XML a Database?

XML document is a collection of data. In other words it doesn’t make much difference between the other files that store data. A XML in a database format is a self describing, portable, and can describe data in tree or graph structure. XML is a sort of Database Management System (DBMS).

XML provides storage, schemas, query languages, programming interfaces and so on .It lacks in triggers, queries, multi-user access that a real database constitutes. The main advantage of XML is that the data is portable and it allows you to have nested entries.

XML allows you to preserve physical document structure, supports document level transactions and execute queries in an XML query language.

Mapping the XML document schema to the database schema does the transfer of data between XML documents and a database. Mappings between document schemas and database schemas are performed on attributes and text. There are 2 mappings that are generally used to map on XML document schema to the database schema:

1. TABLE BASED MAPPING
2. OBJECT RELATIONAL MAPPING

Native XML databases are designed especially to store XML documents .It is always possible to store data in XML documents in a native XML database. This is done so, when your data is semi-structured. Although, this kind of data can be stored in object oriented and hierarchical databases, it is always better to store it in a native XML database. It enables us to retrieve data much faster than a relational database. One more reason is to store data in a native XML database is to exploit XML specification capabilities, such as executing XML queries.

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