Release 10.1A: OpenEdge Development:
Open Client Introduction and Programming

Preface

This Preface contains the following sections:

Purpose
Audience
Organization
Typographical conventions
Examples of syntax descriptions

Purpose

The AppServer™ for OpenEdge® applications excels at encapsulating business functions written in the Progress® 4GL and making them available to 4GL client applications anywhere on an enterprise network. With the Open Client Toolkit (a component of Progress OpenEdge Studio), you can now extend your departmental applications (for example, written in .NET) or your Web-enabled applications written in Java™ to work with the same business functions used by your Progress enterprise applications.

Using the Open Client Toolkit, you can create Open Client interfaces to a Java or .NET application or a Web service definition, to access the business functions on an AppServer. This guide describes how to use the tools provided with the Open Client Toolkit to accomplish this task.

Audience

This guide assumes that you are experienced in programming Java applications and applets, .NET applications, or Web services for your development and deployment environment, and that you have access to documentation on OpenEdge Release 10, especially OpenEdge Application Server: Developing AppServer Applications and its prerequisites.

Before building an application with the help of the Open Client Toolkit, you should be familiar with the information provided by the first two chapters of OpenEdge Application Server: Developing AppServer Applications .

Organization

Chapter 1 "Overview"

Describes the basic mechanisms provided to access AppServer functionality from a non-Progress (Open Client) application.

Chapter 2 "Configuration"

Details the configuration requirements for developing Open Client applications.

Chapter 3 "Generating Proxies and Web Service Definitions"

Explains how to use the Open Client Proxy Generator (ProxyGen) to encapsulate any 4GL API available on an AppServer for access by an Open Client application, and how to manage the result for the application environment.

Chapter 4 "Programming Concepts"

Describes the mechanisms and techniques available to access the functionality encapsulated by ProxyGen from all Open Client applications.

Typographical conventions

This manual uses the following typographical conventions:

Convention	Description
Bold	Bold typeface indicates commands or characters the user types, provides emphasis, or the names of user interface elements.
Italic	Italic typeface indicates the title of a document, or signifies new terms.
SMALL, BOLD CAPITAL LETTERS	Small, bold capital letters indicate OpenEdge® key functions and generic keyboard keys; for example, GET and CTRL.
KEY1+KEY2	A plus sign between key names indicates a simultaneous key sequence: you press and hold down the first key while pressing the second key. For example, CTRL+X.
KEY1 KEY2	A space between key names indicates a sequential key sequence: you press and release the first key, then press another key. For example, ESCAPE H.
Syntax:
Fixed width	A fixed-width font is used in syntax statements, code examples, system output, and filenames.
Fixed-width italics	Fixed-width italics indicate variables in syntax statements.
Fixed-width bold	Fixed-width bold indicates variables with special emphasis.
UPPERCASE fixed width	Uppercase words are Progress® 4GL language keywords. Although these are always shown in uppercase, you can type them in either uppercase or lowercase in a procedure.
	This icon (three arrows) introduces a multi-step procedure.
	This icon (one arrow) introduces a single-step procedure.
Period (.) or colon (:)	All statements except DO, FOR, FUNCTION, PROCEDURE, and REPEAT end with a period. DO, FOR, FUNCTION, PROCEDURE, and REPEAT statements can end with either a period or a colon.
[ ]	Large brackets indicate the items within them are optional.
[ ]	Small brackets are part of the Progress 4GL language.
{ }	Large braces indicate the items within them are required. They are used to simplify complex syntax diagrams.
{ }	Small braces are part of the Progress 4GL language. For example, a called external procedure must use braces when referencing arguments passed by a calling procedure.
|	A vertical bar indicates a choice.
...	Ellipses indicate repetition: you can choose one or more of the preceding items.

Examples of syntax descriptions

In this example, ACCUM is a keyword, and aggregate and expression are variables:

Syntax

ACCUM aggregate expression

FOR is one of the statements that can end with either a period or a colon, as in this example:

FOR EACH Customer:   DISPLAY Name. END.

In this example, STREAM stream, UNLESS-HIDDEN, and NO-ERROR are optional:

Syntax

DISPLAY [ STREAM stream ] [ UNLESS-HIDDEN ] [ NO-ERROR ]

In this example, the outer (small) brackets are part of the language, and the inner (large) brackets denote an optional item:

Syntax

INITIAL [ constant [ , constant ] ]

A called external procedure must use braces when referencing compile-time arguments passed by a calling procedure, as shown in this example:

Syntax

{ &argument-name }

In this example, EACH, FIRST, and LAST are optional, but you can choose only one of them:

Syntax

PRESELECT [ EACH | FIRST | LAST ] record-phrase

In this example, you must include two expressions, and optionally you can include more. Multiple expressions are separated by commas:

Syntax

MAXIMUM ( expression , expression [ , expression ] ... )

In this example, you must specify MESSAGE and at least one expression or SKIP [ (n) ], and any number of additional expression or SKIP [ ( n ) ] is allowed:

Syntax

MESSAGE { expression | SKIP [ ( n ) ] } ...

In this example, you must specify {include-file, then optionally any number of argument or &argument-name = "argument-value", and then terminate with }:

Syntax

{ include-file     [ argument | &argument-name = "argument-value" ] ... }

Long syntax descriptions split across lines

Some syntax descriptions are too long to fit on one line. When syntax descriptions are split across multiple lines, groups of optional and groups of required items are kept together in the required order.

In this example, WITH is followed by six optional items:

Syntax

WITH [ ACCUM max-length ] [ expression DOWN ]   [ CENTERED ] [ n COLUMNS ] [ SIDE-LABELS ]   [ STREAM-IO ]

Complex syntax descriptions with both required and optional elements

Some syntax descriptions are too complex to distinguish required and optional elements by bracketing only the optional elements. For such syntax, the descriptions include both braces (for required elements) and brackets (for optional elements).

In this example, ASSIGN requires either one or more field entries or one record. Options available with field or record are grouped with braces and brackets:

Syntax

ASSIGN   { [ FRAME frame ] { field [ = expression ] }             [ WHEN expression ] } ...        | { record [ EXCEPT field ... ] }