Glossary

application server

An application server is designed to help make it easier for developers to isolate the business logic in their projects (usually through components) and develop three-tier applications. Many application servers also offer additional features such as transaction management, clustering and fail-over, and load balancing.

In the context of WebLogic Workshop, the term application server refers specifically to a Java Application Server, which is an application server that complies with the Java 2 Enterprise Edition (J2EE) platform.

BEA WebLogic Server™, on which WebLogic Workshop is built, is a Java Application Server.

asynchronous

In distributed application architectures like web services, clients invoke methods (or send messages to) servers and servers respond. If the client is blocked from performing other work while waiting for the server to respond, the interaction is referred to as synchronous because the client is synchronized with the server.

If the interaction is designed such that the client can continue performing other work while the server prepares its response, with the server notifying the client when the response is ready, it is referred to as asynchronous.

An asynchronous architecture is useful in event-driven scenarios, in which an event can arrive at any time and the receiver handles the event whenever it arrives.

buffering

You can add a buffer to a method of your service to ensure that it returns to the client immediately, so that the client need not wait for the server to process other requests. Incoming calls to a buffered method are queued so that the server is not overwhelmed with requests.

callback

A callback is a method defined on the client which can be called by your service. Callbacks make it possible to have an asynchronous two-way exchange between a client and a service. For example, if the service performs an operation that takes awhile, the service can immediately acknowledge the client's request with a simple return value, then later use the callback to return the full result of the operation. A callback must participate in a conversation.

callback handler

A callback handler is a method of your service which runs when the service receives the corresponding callback. The method is defined by the control that includes the callback. For example, the timer control provides a callback handler, the onTimeout method, to which you can add code to run when the timer fires.

client (of a web service)

A client makes a request to a web service to return data. The client can be written in any language and running on any platform, so long as it communicates in the manner that the web service expects. Most web services expect to receive requests over an Internet protocol such as HTTP, and they expect those requests to be XML messages formatted according to the SOAP specification.

control

A control is a component that you can incorporate into your web service so that it can communicate with other kinds of applications and components. For example, a database control enables your web service to request data from a database. A Service control makes it easy to call another web service.

control method

A method that allows the web service to invoke the functionality of the data resource.

conversation

A conversation is a sequence of interactions that may occur between a client and a web service. A single instance of a web service conversation has state associated with it that persists for the lifetime of the conversation. At a minimum, this state includes a “conversation ID” which is used to correlate messages coming in and out of the service with a specific conversation instance. This means that if you are processing 1000 credit checks for 1000 people, WebLogic Workshop automatically keeps a unique conversation open for each, and it correlates messages coming in and out with the appropriate conversation.

correlation

Correlation refers to a capability WebLogic Workshop automatically provides to web services. If a web service has many simultaneous clients, it must keep track of which responses go to which clients in response to requests. This includes callbacks: when events occur in the web service that must be passed on to clients via callbacks, WebLogic Workshop's correlation capability routes the callback messages automatically.

CTRL file

A file that contains one or a set of control methods.

deployment

Deployment refers to the act of moving a web service from a development environment to a production environment. Since WebLogic Workshop's runtime is integrated with the WebLogic Server, deployment is very simple for WebLogic Workshop web services: just copy the JWS file (and any supporting files) to the production server and the web service is deployed.

ECMAScript

ECMA is the European Computer Manufacturers Association, the organization that acted as the standards body for ECMAScript.

ECMAScript is the standardized, combined form of the JavaScript and JScript languages. JavaScript was developed by Netscape Communications and JScript was developed by Microsoft Corporation.

lifetime, of web service

A particular instance of a WebLogic Workshop web service exists in the WebLogic Server for a length of time that is controlled by the web service developer. If a web service does not manage conversations, the web service may be created and destroyed each time it is invoked. If the web service manages conversations, each conversation has a lifetime. If no interactions happen in a conversation within a specified timeout interval, the conversation instance will be released. You can also specify, implicitly or explicitly, that a conversation should end when one or more particular methods or callbacks are invoked.

operation

A method that is exposed to a client.

Service control

A Service control makes it easy to communicate with another web service from within your web service. You can create a Service control from any target service's WSDL.

shape (of XML)

XML shape refers to the structure and organization of an XML document, including its hierarchy and order of elements.

SOAP

SOAP, or Simple Object Access Protocol, is a standard set of rules for formatting an XML message so that it can be interpreted by different web services.

SQL

SQL is the acronym for Structured Query Language. See www.sql.org. SQL is a semi-standard language used to communicate with relational databases. SQL statements or queries are used to create, manipulate, query, update and delete tables and records.

synchronous

In simple terms, a method is synchronous if it returns a value. The term comes from the fact that a caller to a synchronous method must wait for the called method to return. The caller is synchronized with the method.

See also asynchrony.

UDDI

Acronym for Universal Description, Discovery and Integration. See www.uddi.org.

web service

An Web Service is a language-independent, platform-independent, self-describing code module that applications can access via a network or the Internet. The application can have the service's location hard-coded or can locate it using UDDI (Universal Description, Discovery, and Integration). Because the service is self-describing, the application can determine which functions are available and how to call them.

well-formed

A quality of an XML document that conforms to XML syntax rules. For a document in use, syntax rules are typically enforced by an XML parser.

WSDL

WSDL is the acronym for Web Services Description Language, the markup language used to describe a web service so that it can be called by diverse clients.

XML map

An XML map correlates the data in an XML message to the parameters and return values of a Java method in your web service. XML maps offer you greater freedom in terms of how you implement the code in your web service, because you are not tied to a particualar XML shape.