Wednesday Jan 27, 2010

Recording of a dmonstration of the "GlassFish ESB v2.2 Field Notes - Exercising Load Balanced, Highly Available, Horizontally Scalable HL7 v2 Processing Solutions"

In the blog entry "GlassFish ESB v2.2 Field Notes - Exercising Load Balanced, Highly Available, Horizontally Scalable HL7 v2 Processing Solutions" I present the GlassFish ESB v2.2-based load balanced, highly available, horizontally scalable solution for HL7 v2.x delimited messaging, using both the HL7 Binding Components, Web Services and JMS in request/reply mode. The one and a half hour recording of me discussing and demonstrating this solution is available as a Flash Movie (SWF), "GFESB_LB_HA_Demo_Session SWF " through the blog article Recording of a dmonstration of the “GlassFish ESB v2.2 Field Notes – Exercising Load Balanced, Highly Available, Horizontally Scalable HL7 v2 Processing Solutions” at http://blogs.czapski.id.au/2010/01/recording-of-a-dmonstration-of-the-glassfish-esb-v2-2-field-notes-exercising-load-balanced-highly-available-horizontally-scalable-hl7-v2-processing-solutions

Wednesday Jan 13, 2010

GlassFish ESB v2.2 - Processing Explicit HL7 v2 Accept Acknowledgements

The HL7 v2 standard mandates the use of acknowledgments to ensure message delivery, critical in Healthcare. There are the “Original Mode” acknowledgements and “Enhanced Mode” acknowledgements. Within the enhanced mode acknowledgements there are “Accept Acknowledgements” and “Application Acknowledgements”.

This Note walks through development of two BPEL Module-based solutions that cooperate in generating and processing Enhanced Accept Acknowledgements using HL7 v2.3.1 messages. This discussion should apply to any v2.x, greater then v2.2, where the Enhanced Mode acknowledgements were introduced. In addition, the solutions are used to illustrate receiving HL7 BC ACK generation, when receiving an invalid HL7 message.

The blog article and the related material are available at http://blogs.czapski.id.au/2010/01/glassfish-esb-v2-2-processing-explicit-hl7-v2-accept-acknowledgements

Tuesday Jan 05, 2010

GlassFish ESB v2.2 Field Notes - Exercising Load Balanced, Highly Available, Horizontally Scalable HL7 v2 Processing Solutions

It seems frequently assumed that architecting and deploying Highly Available (HA) solutions requires Application Server and/or Operating System clustering. When it comes to SOA and Integration solutions this is not necessarily a correct assumption. Load Balanced (LB) and Highly Available HA) SOA and Integration solutions may not require that degree of complexity and sophistication. Frequently, protocol, binding component, JBI and architectural application design properties can be exploited to design highly available solutions. Testing LB and HA solutions requires infrastructure consisting of multiple hosts and the ability to “crash” hosts at will. With virtualization technologies available now it is far easier to use multiple virtual machines then to use physical machines. It is also easier and potentially less destructive to “crash” virtual machines then it is to do so with physical machines.

In this Note a heterogeneous, non-clustered collection of hosts will be used to implement and exercise three load balanced, highly available GlassFish ESB-based solutions. The environment consists of a number of independent “machines”, which are not a part of an Operating System Cluster. Each “machine” hosts a GlassFish Application Server. Application Servers are independent of one another and are not clustered. This is to demonstrate that load balanced, highly available, horizontally scalable solutions, based on the GlassFish ESB software alone, can be designed and implemented.

The specific class of solutions to which this discussion applies is the class of solutions which:
1.    are exposed as request/reply services
a.    HL7 messaging with explicit Application Acknowledgment
or
b.    Request/Reply Web Services
or
c.    JMS in Request/Reply mode
2.    implement business logic as short lived processes
3.    are
a.    atomic
or
b.    are idempotent
or
c.    tolerant of duplicate messages
Classes of solutions with characteristics different from these named above require different approaches to high availability and horizontal scalability, and are not discussed here.

In this Note only high availability and scalability of receiver solutions is addressed. This aspect is the focus because a failure to process a message by a receiver may result in message loss –generally a bad thing.

Paradoxical as it may sound; senders are special cases of receivers. Just as a receiver is triggered by arrival of a message so too is a sender. Making sure that the sender trigger message does not get lost is much the same as making sure the message a receiver receives does not get lost. This means that the same considerations apply to senders and to receivers.

This note discusses an exercise involving an example load balanced, highly available, horizontally scalable healthcare environment, processing HL7 v2 messages. Discussion includes customization of generic GlassFish ESB v2.2 VMware Virtual Appliances for a specific Load Balancing and High Availability exercise and deploying ready-made GlassFish ESB solutions. The exercise for HL7 BC-based, Web Service-based and JMS-based highly available, load balanced, and horizontally scalable receivers, processing HL7 v2.3.1 messages, will be conducted and discussed.

At the end of the Note we will have three GlassFish ESB VMware Appliances with GlassFish ESB v2.2 Runtime infrastructure, ready to use for further GlassFish ESB Load Balancing and High Availability exercises.

The reader will be convinced, one hopes, that for the applicable class of GlassFish ESB-based solutions, load balancing and dynamic failover without message loss work. For that class of solutions this provides for high availability and horizontal scalability without resorting to Application Server or Operating System clustering.

The article is available at http://blogs.czapski.id.au/2010/01/glassfish-esb-v2-2-field-notes-exercising-load-balanced-highly-available-horizontally-scalable-hl7-v2-processing-solutions

Friday Jul 03, 2009

GlassFish ESB v2.1, MySQL v5.1 - Make HL7 v2.3.1 Delimited Messages from Custom Delimited Records with HL7 Encoder and HL7 BC

“Progress” notwithstanding, Healthcare environments still extensively use the HL7 v2.x Delimited messages for conveyance of patient and patient-related information between applications. The GlassFish ESB provides support for HL7 v2.x messaging in the form of the HL7 Encoder, which allows conversion between HL7 v2 Delimited and HL7 v2 XML message formats, and in the form of the HL7 Binding Component, which allow connectivity between the GlassFish ESB-based healthcare solutions and healthcare applications that support HL7 over TCP connectivity.

In this document I will walk through the process of generating HL7 v2.3.1 delimited messages from pipe-delimited records containing patient information, sending and receiving HL7 v2.3.1 delimited messages using the HL7 Binding Component, parsing HL7 v2.3.1 delimited messages and writing HL7 v2 delimited messages to a file. To create and process HL7 messages I show how create a custom ADT A04 XML Schema and a custom “any HL7 v2 message” XML Schema. This gives me an opportunity to use the File Binding Component (File BC), the HL7 BC, the HL7 Encoder, the Custom Encoder and the BPEL Service Engine (BPEL SE). This also gives me an opportunity to demonstrate a HL7 v2.3.1 delimited message sender solution and to demonstrate a HL7 v2.3.1 delimited message receiver solution. At the end of the process we will have a file containing HL7 v2 delimited ADT A04 messages, which we will use in related writeups. 

The article and referenced materials are available at http://blogs.czapski.id.au/2009/07/glassfish-esb-v2-1-mysql-v5-1-make-hl7-v2-3-1-delimited-messages-from-custom-delimited-records-with-hl7-encoder-and-hl7-bc
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In this Blog I post abstracts of articles / writeups / notes on various aspects of Java CAPS and SOA Suite including solutions, discussions and screencasts. The links to the referenced material are included in the bodies of the abstracts.

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