org.jboss.gravia.resolver

Interface ResolveContext

All Known Implementing Classes:

AbstractResolveContext, DefaultResolveContext

public interface ResolveContext

A resolve context provides resources, options and constraints to the potential solution of a resolve operation.

Resolve Contexts:

• Specify the mandatory and optional resources to resolve. The mandatory and optional resources must be consistent and correct. For example, they must not violate the singleton policy of the implementer.
• Provide capabilities that the Resolver can use to satisfy requirements via the findProviders(Requirement) method
• Constrain solutions via the getWirings() method. A wiring consists of a map of existing resources to wiring.
• Filter requirements that are part of a resolve operation via the isEffective(Requirement).

A resolver may call the methods on the resolve context any number of times during a resolve operation using any thread. Implementors should ensure that this class is properly thread safe.

The resolve context methods must be idempotent. This means that resources must have constant capabilities and requirements and the resolve context must return a consistent set of capabilities, wires and effective requirements.

Since:

02-Apr-2012

Author:

thomas.diesler@jboss.com

Method Summary

Methods

Modifier and Type	Method and Description
List<org.jboss.gravia.resource.Capability>	findProviders(org.jboss.gravia.resource.Requirement requirement) Find Capabilities that match the given Requirement.
Collection<org.jboss.gravia.resource.Resource>	getMandatoryResources() Return the resources that must be resolved for this resolve context.
Collection<org.jboss.gravia.resource.Resource>	getOptionalResources() Return the resources that the resolver should attempt to resolve for this resolve context.
Map<org.jboss.gravia.resource.Resource,org.jboss.gravia.resource.Wiring>	getWirings() Returns the wirings for existing resolved resources.
boolean	isEffective(org.jboss.gravia.resource.Requirement requirement) Test if a given requirement should be wired in the resolve operation.

Method Detail

getMandatoryResources

Collection<org.jboss.gravia.resource.Resource> getMandatoryResources()

Return the resources that must be resolved for this resolve context.

The default implementation returns an empty collection.

Returns:

The resources that must be resolved for this resolve context. May be empty if there are no mandatory resources.

getOptionalResources

Collection<org.jboss.gravia.resource.Resource> getOptionalResources()

Return the resources that the resolver should attempt to resolve for this resolve context. Inability to resolve one of the specified resources will not result in a resolution exception.

The default implementation returns an empty collection.

Returns:

The resources that the resolver should attempt to resolve for this resolve context. May be empty if there are no mandatory resources.

findProviders

List<org.jboss.gravia.resource.Capability> findProviders(org.jboss.gravia.resource.Requirement requirement)

Find Capabilities that match the given Requirement.

The returned list contains Capability objects where the Resource must be the declared Resource of the Capability.

The returned list is in priority order such that the Capabilities with a lower index have a preference over those with a higher index.

Each returned Capability must match the given Requirement.

Parameters:

requirement - The requirement that a resolver is attempting to satisfy. Must not be null.

Returns:

A list of Capability objects that match the specified requirement.

isEffective

boolean isEffective(org.jboss.gravia.resource.Requirement requirement)

Test if a given requirement should be wired in the resolve operation. If this method returns false, then the resolver should ignore this requirement during the resolve operation.

The primary use case for this is to test the effective directive on the requirement, though implementations are free to use any effective test.

Parameters:

requirement - The Requirement to test. Must not be null.

Returns:

true if the requirement should be considered as part of the resolve operation.

getWirings

Map<org.jboss.gravia.resource.Resource,org.jboss.gravia.resource.Wiring> getWirings()

Returns the wirings for existing resolved resources.

Multiple calls to this method for this resolve context must return the same result.

Returns:

The wirings for existing resolved resources. The returned map is unmodifiable.