org.osgi.service.resolver.Resolver Maven / Gradle / Ivy
/*
* Copyright (c) OSGi Alliance (2006, 2019). All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.osgi.service.resolver;
import java.util.List;
import java.util.Map;
import org.osgi.annotation.versioning.ProviderType;
import org.osgi.framework.namespace.PackageNamespace;
import org.osgi.resource.Namespace;
import org.osgi.resource.Requirement;
import org.osgi.resource.Resource;
import org.osgi.resource.Wire;
import org.osgi.resource.Wiring;
/**
* A resolver service resolves the specified resources in the context supplied
* by the caller.
*
* @ThreadSafe
* @author $Id: e4011e12a98088d382bb7f5b27817213734f6504 $
*/
@ProviderType
public interface Resolver {
/**
* Resolve the specified resolve context and return any new resources and
* wires to the caller.
*
*
* The resolver considers two groups of resources:
*
* - Mandatory - any resource in the
* {@link ResolveContext#getMandatoryResources() mandatory group} must be
* resolved. A failure to satisfy any mandatory requirement for these
* resources will result in throwing a {@link ResolutionException}
* - Optional - any resource in the
* {@link ResolveContext#getOptionalResources() optional group} may be
* resolved. A failure to satisfy a mandatory requirement for a resource in
* this group will not fail the overall resolution but no resources or wires
* will be returned for that resource.
*
*
*
* The resolve method returns the delta between the start state defined by
* {@link ResolveContext#getWirings()} and the end resolved state. That is,
* only new resources and wires are included.
*
*
* The behavior of the resolver is not defined if the specified resolve
* context supplies inconsistent information.
*
* @param context The resolve context for the resolve operation. Must not be
* {@code null}.
* @return The new resources and wires required to satisfy the specified
* resolve context. The returned map is the property of the caller
* and can be modified by the caller.
* @throws ResolutionException If the resolution cannot be satisfied.
*/
Map> resolve(ResolveContext context) throws ResolutionException;
/**
* Resolves a given requirement dynamically for the given host wiring using
* the given resolve context and return any new resources and wires to the
* caller.
*
* The requirement must be a {@link Wiring#getResourceRequirements(String)
* requirement} of the wiring and must use the
* {@link PackageNamespace#PACKAGE_NAMESPACE package} namespace with a
* {@link Namespace#REQUIREMENT_RESOLUTION_DIRECTIVE resolution} of type
* {@link PackageNamespace#RESOLUTION_DYNAMIC dynamic}.
*
* The resolve context is not asked for
* {@link ResolveContext#getMandatoryResources() mandatory} resources or for
* {@link ResolveContext#getMandatoryResources() optional} resources. The
* resolve context is asked to
* {@link ResolveContext#findProviders(Requirement) find providers} for the
* given requirement. The matching {@link PackageNamespace#PACKAGE_NAMESPACE
* package} capabilities returned by the resolve context must not have a
* {@link PackageNamespace#PACKAGE_NAMESPACE osgi.wiring.package} attribute
* equal to a {@link PackageNamespace#PACKAGE_NAMESPACE package} capability
* already {@link Wiring#getRequiredResourceWires(String) wired to} by the
* wiring or equal a {@link PackageNamespace#PACKAGE_NAMESPACE package}
* capability {@link Wiring#getResourceCapabilities(String) provided} by the
* wiring. The resolve context may be requested to
* {@link ResolveContext#findProviders(Requirement) find providers} for
* other requirements in order to resolve the resources that provide the
* matching capabilities to the given requirement.
*
* If the requirement {@link Namespace#REQUIREMENT_CARDINALITY_DIRECTIVE
* cardinality} is not {@link Namespace#CARDINALITY_MULTIPLE multiple} then
* no new wire must be created if the
* {@link Wiring#getRequiredResourceWires(String) wires} of the wiring
* already contain a wire that uses the {@link Wire#getRequirement()
* requirement}
*
* This operation may resolve additional resources in order to resolve the
* dynamic requirement. The returned map will contain entries for each
* resource that got resolved in addition to the specified wiring
* {@link Wiring#getResource() resource}. The wire list for the wiring
* resource will only contain one wire which is for the dynamic requirement.
*
* @param context The resolve context for the resolve operation. Must not be
* {@code null}.
* @param hostWiring The wiring with the dynamic
* {@link Wiring#getResourceRequirements(String) requirement}.
* Must not be {@code null}.
* @param dynamicRequirement The dynamic requirement. Must not be
* {@code null}.
* @return The new resources and wires required to satisfy the specified
* dynamic requirement. The returned map is the property of the
* caller and can be modified by the caller. If no new wires were
* created then a ResolutionException is thrown.
* @throws ResolutionException if the dynamic requirement cannot be resolved
*/
public Map> resolveDynamic(ResolveContext context,
Wiring hostWiring, Requirement dynamicRequirement)
throws ResolutionException;
}