Jan 29

In the major writeup, now called “CH05_WSSecurityExploration_r0.4.2.pdf”, at http://blogs.czapski.id.au/wp-content/uploads/2010/03/CH05_WSSecurityExploration_r0.4.2.pdf, in section 5.14.3, “Using WS-Addressing for Explicit Routing”, I discuss how WS-Addressing can be used to implement a variant of the “Routing Ticket” EIP Pattern. A one-way web service consumer sends a request to a request/reply web service, indicating, using WS-Addressing, the address of a one-way web service to which to send the response.

Jan 29

As I develop bigger prices of work, which have writeups associated with them, I inevitably have to solve small problems that crop up. The problems I solve I typically get written about in the corresponding writeup but may be missed by these who might need these kinds of solutions but who don’t have an interest in the major piece. For example, when writing about the HL7 HA solution, “GlassFish ESB v2.2 Field Notes – Exercising Load Balanced, Highly Available, Horizontally Scalable HL7 v2 Processing Solutions”, at http://blogs.czapski.id.au/?p=13, I had to work what host the instance of the business process was using and how to make the process instance wait for a random amount of time. I did separate writeups on these as “GlassFish ESB v2.1 – Using JavaScript Codelets to Extend BPEL 2.0 Functionality”, at http://blogs.czapski.id.au/?p=17, and “GlassFish ESB v2.1 Field Notes – JavaScript Codelets to Make BPEL Process Wait for a Random Duration Up to a Maximum number of Milliseconds”, at http://blogs.czapski.id.au/?p=16.

Here I call reader’s attention to the problem of reading values of SOAP Headers in a BPEL 2.0 process. I discussed one method in “Java CAPS 5 / 6, OpenESB, GlassFish ESB – Handling SOAP Headers in BPEL”, at http://blogs.czapski.id.au/?p=27. In the major writeup, now called “CH05_WSSecurityExploration_r0.4.2.pdf”, at http://blogs.czapski.id.au/wp-content/uploads/2010/03/CH05_WSSecurityExploration_r0.4.2.pdf, I am discussing, in passing, in Section 5.14.2, “Interacting with WS-Addressing Headers in BPEL”, a method that uses Normalized Message Properties (NMProperties) in BPEL 2.0, to access SOAP headers. While this piece discusses how to access WS-Addressing SOAP headers it is equally applicable to other SOAP headers. Similarly, in section 5.14.3, “Using WS-Addressing for Explicit Routing”, I discuss how arbitrary SOAP headers can be added and populated using NMProperties in BPEL 2.0. So if you need to manipulate SOAP header in BPEL 2.0, have a look a these sections.

The writeup, CH05_WSSecurityExploration_r0.4.2.pdf, is available at http://blogs.czapski.id.au/wp-content/uploads/2010/03/CH05_WSSecurityExploration_r0.4.2.pdf

Jan 05

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 complete Note is available as 03_Conducting_HL7_LB_and_HA_Exercise_v1.0.0.1.pdf at http://blogs.czapski.id.au/wp-content/uploads/2010/03/03_Conducting_HL7_LB_and_HA_Exercise_v1.0.0.1.pdf

Aug 05

This document discusses how the SOAP/HTTP Binding Component can be configured, in a service provider and in a service consumer, to use WS-Security 1.0 (2004) Username Token Profile support. WS-Security 1.0 (2004) provided support for the Username Token, which could be sent over the wire in the clear. This was insecure but Sun JAX-RPC libraries allowed this, since the standard allowed this. Through Project Metro release 1.4 it was impossibly to formulate a WS-Security policy that decorated a SOAP message with the Username Token headers, without requiring to also encrypt parts of the message. This prevented solutions built on top Metro 1.4, or earlier, from supporting cleartext Username Token. Metro 1.5 relaxed this requirement. The WS-Security policy configured using the GlassFish ESB NetBeans WS-Security wizard will be modified to require and provide a Plain text Username Token.

The document is here: 02_Configuring_HTTP_BC_for_WS-Security_UsernameToken.pdf

The companion archive containing all projects is here: WSSecPolicies_PersonUsernamePlain.zip

Jun 24

In some views SOA is represented as a series of 4 layers: Presentation Layer (SOA 1), Business Process Layer (SOA 2), Business Service Layer (SOA 3) and Technical Layer (SOA 4). Typically each layer higher up in the hierarchy consumes services exposed by the layer under it. So the Presentation Layer would consume services provided by the Business Process or Business Service Layers. Service interfaces are described using Web Services Description Language (WSDL), sheltering service consumers from details of service implementation. Web Services are seen as the technical means to implement the decoupled functional layers in a SOA development. Decoupling allows implementations of business functionality at different layers to be swapped in and out without disturbing other layers in the stack. The SOA 1, Presentation Layer, is often implemented as JSR-168-compliant or JSR-286-complaint Portlets, exposed through a standards-based Portal.

The business idea is that patients are looked after in various healthcare facilities. Applications need to allow selection of a facility and to access facility details for display to human operators. A relational holds details of facilities which are a part of the healthcare enterprise. Facility list and details are available through a web service. This web service will be used to construct the JSR-286-comliant Portlet that provides a user view into the facilities and facility details. This Portlet will be deployed to the Sun FOSS Web Space Server 10 Portal.

Previous documents in this series, “GlassFish ESB v 2.1   Creating a Healthcare Facility Web Service Provider” and “NetBeans 6.5.1 and GlassFish v 2.1 – Creating a Healthcare Facility Visual Web Application”, walked the reader through the process of implementing a GlassFish ESB v2.1-based web service which returns facility list and facility details, and a Visual Web JSF Web Application which used that Web Service to display facility list and details.
In this document I will walk through the process of developing a JSR-286-compliant Visual Web JSF Portlet, deployed to the Sun Web Space Server 10 Portal, which will use the Web Service as a data provider. We will use the NetBeans 6.5.1 IDE, which comes as part of the GlassFish ESB v2.1 installation, the Portal Pack 3.0.1 NetBeans Plugin and the JSF Portal Bridge infrastructure provided by the Web Space Server 10. The Portlet will be implemented as a Visual Web JavaServer Faces Portlet using JSF components provided by Project Woodstock. The Portlet will introduce the technology in a practical manner and will show how a web service can be used as a data provider, decoupling the web application from the data stores and specifics of data provision.

Note that this document is not a tutorial on JavaServer Faces, Visual Web JSF, Project Woodstock components or Portlet development. Note also that all the components and technologies used are either distributed as part of the NetBeans 6.5, as part of the GalssFish ESB v2.1, as part of the Web Space Server 10 or are readily pluggable into the NetBeans IDE. All are free and open source.

Here is the document: 01_FacilityService_WebSpacePortlet.pdf

Jun 22

In some views SOA is represented as a series of 4 layers: Presentation Layer (SOA 1), Business Process Layer (SOA 2), Business Service Layer (SOA 3) and Technical Layer (SOA 4). Typically each layer higher up in the hierarchy consumes services exposed by the layer under it. So the Presentation Layer would consume services provided by the Business Process or Business Service Layers. Service interfaces are described using Web Services Description Language (WSDL), sheltering service consumers from details of service implementation. Web Services are seen as the technical means to implement the decoupled functional layers in a SOA development. Decoupling allows implementations of business functionality at different layers to be swapped in and out without disturbing other layers in the stack.
In this document I will walk through the process of developing a SOA Composite Application, exposed as a Web Service, which will make available simple business functionality using a multi-operation service. We will use the GalssFish ESB v2.1 infrastructure. The service will use the SOAP/HTTP Binding Component, the Database Binding Component and the BPEL 2.0 Service Engine. This simple service will introduce the components and discuss how a multi-operation web service can be constructed using the GalssFish ESB.
The business idea is that patients are looked after in various healthcare facilities. Frequently applications need to allow selection of a facility and to access facility details for display to human operators. A relational database is used to hold the details of facilities which are a part of the healthcare enterprise. To shelter application developers from the details of the data store facility list and details will be made available as a multi-operation web service. This web service will be used elsewhere to construct a portlet that can be used in an enterprise portal.

The document is available as 01_FacilityService_GFESBv21.pdf

Late breaking news: The MySQL JDBC Driver, which I used in the example, mysql-connector-java-5.1.7-bin.jar, and which is distributed with the GlassFish ESB v2.1, causes connection pool exhaustion and other issues with the example. If you experience these issues pleases download the latest MySQL JDBC Driver, mysql-connector-java-5.1.11-bin.jar as at now, from http://dev.mysql.com/downloads/connector/j/5.1.html and replace the original in domains/domain1/lib/ext.

Jun 20

It is likely that, at some point or another, a SOA-based solution will require a graphical user interface. In a typical 4 layer SOA stack SOA 1, the Presentation Layer, is delivered as a series of Web Applications, by preferences through a Portal-based solution. Sun Web Space Server 10 is a Free and Open Source Portal solution that can be readily integrated into a SOA infrastructure, for example one based on the GlassFish ESB v2.1 – the Free and Open Source ESB. How Web Space Server can be added to the GlassFosh ESB v2.1 infrastructure is discussed in the blog entry “Adding Sun WebSpace Server 10 Portal Server functionality to the GlassFish ESB v2.1 Installation”.
Web Space Server takes over the web container, in a manner of speaking, causing all web references to be redirected through to the portal infrastructure. This makes it impossible to interact with web services deployed to the instance of GlassFish. Web Services and Web Space Server do not play nicely together when installed in the manner discussed in the Blog.

This document provides instructions which will allow Web Services and Web Space Server to play nicely in the same instance of GlassFish by changing the servlet context which the Web Space Server manages from / to a different one. This will allow all other servlet contexts to be treated qas though the Web Space Server was not installed and will allow the two sets of functionality to coexist.

The credit for this solution goes to users@webspace.dev.java.net, in particular Srikanth Konjarla, Deepak Gothe and Allan Foster.

Here is the document, MakingWebSpaceServerAndWebServicesPlayNicely.pdf.

Feb 14

If we overlook the fact that using web services to transfer large payloads is a very stupid idea, we will be faced with the need to implement the optimisation mechanisms to make transfer of large payloads using web services a little less inefficient from the stand point of the size of the over-the-wire data to be transferred. The standardised, supported mechanism for this is the Message Transmission Optimisation Method (MTOM), http://en.wikipedia.org/wiki/MTOM. Java CAPS Repository-based Web Services don’t offer a convenient mechanism to provide MTOM support.

This note walks through the implementation of a Java CAPS Repository-based, eInsight-based web service consumer and the implementation of the EJB-based Web Service Wrapper Consumer for this service, which provides support for MTOM. The Note discusses how to exercise the wrapper service using the NetBeans web services testing facilities, how to trigger the Java CAPS Repository-based web service invoker and how to observe on-the-wire message exchanges. The invoker implementations discussed in this Note will invoke the web service providers discussed in an earlier Note, “Java CAPS – Exposing MTOM-capable Java CAPS Classic Web Service”, http://blogs.sun.com/javacapsfieldtech/entry/java_caps_exposing_mtom_capable.

The note is available as Invoking_MTOM-WS_using_Java_CAPS_Classic.pdf

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Feb 12

If we overlook the fact that using web services to transfer large payloads is a very stupid idea, we will be faced with the need to implement the optimisation mechanisms to make transfer of large payloads using web services a little less inefficient from the stand point of the size of the over-the-wire data to be transferred.

The standardised, supported mechanism for this is the Message Transmission Optimisation Method (MTOM), http://en.wikipedia.org/wiki/MTOM. Java CAPS Repository-based Web Services don’t offer a convenient mechanism to provide MTOM support.

This note walks through the implementation of a Java CAPS Repository-based, eInsight-based web service and the implementation of the EJB-based Web Service Wrapper for this service, which provides support for MTOM. The Note discusses how to exercise the services using the NetBeans web services testing facilities and how to observe on-the-wire message exchanges.

The note is available as Exposing_MTOM-capable_Java_CAPS_Classic_Web_Service.pdf

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