1. Introduction

This document, Web Services Policy 1.5 - Primer, provides an introductory description of the Web Services Policy language and should be read alongside the formal descriptions contained in the WS-Policy and WS-PolicyAttachment specifications.

This document is:

• for policy expression authors who need to understand the syntax of the language and understand how to build consistent policy expressions,
• for policy implementers whose software modules read and write policy expressions and
• for policy assertion authors who need to know the features of the language and understand the requirements for describing policy assertions.

This document assumes a basic understanding of XML 1.0, Namespaces in XML, WSDL 1.1 and SOAP.

Each major section of this document introduces the features of the policy language and describes those features in the context of concrete examples.

2. Basic Concepts: Policy Expression covers the basic mechanisms of Web Services Policy. It describes how to declare and combine capabilities and requirements of a Web service as policy expressions, attach policy expressions to WSDL constructs such as endpoint and message, and re-use policy expressions.

3. Advanced Concepts I: Policy Expression this is the first advanced section that provides more in-depth materials for policy implementers and assertion authors. It explains the basics of normalizing policy expressions, merging policies, determining the compatibility (intersection) of policies, the policy data model, the policy expression and the extensibility points built into the Web Services Policy language.

4. Advanced Concepts II: Policy Assertion Design this is the second advanced section that walks through the dimensions of a policy assertion for assertion authors. This section describes the role of policy assertions, parts of a policy assertion, when to design policy assertions, outlines guidelines for designing policy assertions and enumerates the minimum requirements for describing policy assertions in specifications.

The Web Services Policy 1.5 - Guidelines for Policy Assertion Authors specification provides guidelines for designing policy assertions and enumerates the minimum requirements for describing policy assertions in specifications.

This is a non-normative document and does not provide a definitive specification of the Web Services Policy language. B. XML Namespaces lists all the namespaces that are used in this document. (XML elements without a namespace prefix are from the Web Services Policy XML Namespace.)