org.nhindirect.policy

Interface PolicyExpression

All Superinterfaces:

java.io.Serializable

All Known Subinterfaces:

ExtensionField<P>, LiteralPolicyExpression<P>, OperationPolicyExpression, ReferencePolicyExpression<R,P>, TBSField<P>, X509Field<P>

All Known Implementing Classes:

AbstractExtensionField, AbstractTBSField, AbstractX509Field, AuthorityInfoAccessExtentionField, AuthorityInfoAccessOCSPLocExtentionField, AuthorityKeyIdentifierKeyIdExtensionField, BasicContraintsExtensionField, CertificatePolicyCpsUriExtensionField, CertificatePolicyIndentifierExtensionField, CRLDistributionPointNameExtentionField, ExtendedKeyUsageExtensionField, IssuerAttributeField, KeyUsageExtensionField, OperationPolicyExpressionFactory.OperationPolicyExpressionImpl, SerialNumberAttributeField, SignatureAlgorithmField, SubjectAltNameExtensionField, SubjectAttributeField, SubjectKeyIdentifierExtensionField, SubjectPublicKeyAlgorithmField, SubjectPublicKeySizeField

public interface PolicyExpression
extends java.io.Serializable

Expressions are the building blocks of building policy statements. Expressions can be simple literals or a complex series of operations that take other expressions as parameters.
PolicyExpression objects are generally the resulting intermediate state of a parsed PolicyLexicon before being further processed by the policy engine Compiler.
Expressions are categorized into three types.

• Literals: Literals are simply primitive types or objects that have a static value. In the policy engine, literals are represented by PolicyValue objects.
• References: References are objects whose values are evaluated at runtime similar to variables. Reference may be simple structures or specific structure types such as X509 certificates.
• Operations: Operations are a combination of a PolicyOperator and one or more parameters. Operator parameters are themselves expressions allowing parameters to be either literals, references, or the result of another operation.
  Because operator parameters are expressions, complex expressions can be built by nesting other operations as parameters resulting in a tree like construct. Expressions are built using the either the LiteralPolicyExpressionFactory, the OperationPolicyExpressionFactory, or by instantiating one of the defined reference structures in the org.nhindirect.policy.x509 package.

Since:

1.0

Author:

Greg Meyer

Method Summary

Modifier and Type	Method and Description
PolicyExpressionType	getExpressionType() Gets the expression type.

Method Detail

getExpressionType

PolicyExpressionType getExpressionType()

Gets the expression type.

Returns:

The expression type.