/*
* #%L
* Gravia :: Resolver
* %%
* Copyright (C) 2010 - 2014 JBoss by Red Hat
* %%
* 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.
* #L%
*/
package org.jboss.gravia.resolver.spi;
import static org.jboss.gravia.resolver.spi.ResolverLogger.LOGGER;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.NoSuchElementException;
import java.util.Set;
import org.jboss.gravia.resolver.ResolutionException;
import org.jboss.gravia.resolver.ResolveContext;
import org.jboss.gravia.resolver.Resolver;
import org.jboss.gravia.resource.Capability;
import org.jboss.gravia.resource.Requirement;
import org.jboss.gravia.resource.Resource;
import org.jboss.gravia.resource.spi.AbstractResource;
import org.jboss.gravia.runtime.Wire;
import org.jboss.gravia.runtime.Wiring;
import org.jboss.gravia.runtime.spi.AbstractWire;
import org.jboss.gravia.runtime.spi.AbstractWiring;
/**
* An abstract resolver {@link Resolver}.
*
* The resolver maintains order on all levels.
* This should guarantee reproducable results.
*
* @author thomas.diesler@jboss.com
* @since 31-May-2010
*/
public abstract class AbstractResolver implements Resolver {
protected abstract AbstractWire createWire(Requirement req, Capability cap);
protected abstract AbstractWiring createWiring(Resource resource, List<Wire> reqwires, List<Wire> provwires);
@Override
public Map<Resource, List<Wire>> resolve(ResolveContext context) throws ResolutionException {
return resolveInternal((AbstractResolveContext) context, false);
}
@Override
public Map<Resource, List<Wire>> resolveAndApply(ResolveContext context) throws ResolutionException {
return resolveInternal((AbstractResolveContext) context, true);
}
ResourceSpaces createResourceSpaces(ResolveContext context) {
return new ResourceSpaces(context);
}
ResourceCandidates createResourceCandidates(Resource res) {
return new ResourceCandidates(res);
}
private Map<Resource, List<Wire>> resolveInternal(AbstractResolveContext context, boolean apply) throws ResolutionException {
LOGGER.debug("Resolve: mandatory{} optional{}", context.getMandatoryResources(), context.getOptionalResources());
// Get the combined set of resources in the context
Set<Resource> combined = new LinkedHashSet<Resource>();
combined.addAll(context.getMandatoryResources());
combined.addAll(context.getOptionalResources());
// Resolve combined resources
ResolverState state = new ResolverState(context);
for (Resource res : combined) {
resolveResource(state, res);
}
// Log resolver result
Map<Resource, List<Wire>> resourceWires = state.getResult();
if (LOGGER.isDebugEnabled()) {
for (Entry<Resource, List<Wire>> entry : resourceWires.entrySet()) {
LOGGER.debug("Resolved: {}", entry.getKey());
for (Wire wire : entry.getValue()) {
LOGGER.debug(" {}", wire);
}
}
}
// Apply resolver results
if (apply) {
Map<Resource, Wiring> wirings = context.getWirings();
for (Entry<Resource, List<Wire>> entry : resourceWires.entrySet()) {
AbstractResource requirer = (AbstractResource) entry.getKey();
List<Wire> reqwires = entry.getValue();
AbstractWiring reqwiring = (AbstractWiring) wirings.get(requirer);
if (reqwiring == null) {
reqwiring = createWiring(requirer, reqwires, null);
context.putWiring(requirer, reqwiring);
} else {
for (Wire wire : reqwires) {
reqwiring.addRequiredWire(wire);
}
}
for (Wire wire : reqwires) {
AbstractResource provider = (AbstractResource) wire.getProvider();
AbstractWiring provwiring = (AbstractWiring) wirings.get(provider);
if (provwiring == null) {
provwiring = createWiring(provider, null, null);
context.putWiring(provider, provwiring);
}
provwiring.addProvidedWire(wire);
}
}
}
return resourceWires;
}
private ResourceSpace resolveResource(ResolverState state, Resource res) throws ResolutionException {
// Check if we already have a resolved space for resource
ResourceSpaces spaces = state.getResourceSpaces();
ResourceSpace resspace = spaces.getResourceSpace(res);
if (resspace != null)
return resspace;
// A resource can resolve when the spaces of all its immediate dependencies can be added
ResolveContext context = state.getResolveContext();
ResourceCandidates rescan = new ResourceCandidates(res);
Iterator<List<Wire>> itres = rescan.iterator(context);
while (itres.hasNext()) {
Wiring wiring = context.getWirings().get(res);
ResourceSpace space = new ResourceSpace(res, wiring);
List<Wire> wires = itres.next();
boolean allgood = true;
for (Wire wire : wires) {
Resource provider = wire.getProvider();
ResourceSpace provspace = resolveResource(state, provider);
if (!space.addDependencySpace(provspace)) {
allgood = false;
break;
}
}
if (allgood) {
spaces.addResourceSpace(space);
state.getResult().put(res, wires);
return space;
}
}
ResolutionException resex = rescan.getResolutionException();
if (resex != null) {
throw resex;
}
if (spaces.getResourceSpace(res) == null) {
List<Requirement> manreqs = res.getRequirements(null);
Iterator<Requirement> itreqs = manreqs.iterator();
while (itreqs.hasNext()) {
if (itreqs.next().isOptional()) {
itreqs.remove();
}
}
throw new ResolutionException("Requirements map to candidates in disconnected spaces", null, manreqs);
}
return null;
}
private class ResolverState {
private final ResourceSpaces spaces;
private final ResolveContext context;
private final Map<Resource, List<Wire>> wiremap = new LinkedHashMap<Resource, List<Wire>>();
ResolverState(ResolveContext context) {
this.context = context;
this.spaces = new ResourceSpaces(context);
}
ResourceSpaces getResourceSpaces() {
return spaces;
}
ResolveContext getResolveContext() {
return context;
}
Map<Resource, List<Wire>> getResult() {
return wiremap;
}
}
class ResourceSpaces {
private final Map<Resource, ResourceSpace> spacemap = new LinkedHashMap<Resource, ResourceSpace>();
// Initially contain spaces for all wired resources
ResourceSpaces(ResolveContext context) {
Map<Resource, Wiring> wirings = context.getWirings();
for (Resource res : wirings.keySet()) {
Wiring wiring = wirings.get(res);
spacemap.put(res, new ResourceSpace(res, wiring));
}
}
ResourceSpaces(ResourceSpaces parent) {
spacemap.putAll(parent.spacemap);
}
void addResourceSpace(ResourceSpace space) {
Resource primary = space.getPrimary();
assert !spacemap.containsKey(primary) : "spaces does not contain: " + primary;
spacemap.put(primary, space);
}
Map<Resource, ResourceSpace> getResourceSpaces() {
return Collections.unmodifiableMap(spacemap);
}
ResourceSpace getResourceSpace(Resource res) {
return spacemap.get(res);
}
}
/**
* A {@link ResourceSpace} is that of a primary {@link Resource} and its immediate dependencies.
* A space cannot contain two versions of the same {@link Resource}.
*/
class ResourceSpace {
private final Resource primary;
private final Map<String, Resource> resources = new LinkedHashMap<String, Resource>();
ResourceSpace(Resource primary, Wiring wiring) {
this.primary = primary;
String uniquekey = primary.getIdentity().getSymbolicName();
resources.put(uniquekey, primary);
if (wiring != null) {
for (Wire wire : wiring.getRequiredResourceWires(null)) {
Resource provider = wire.getProvider();
uniquekey = provider.getIdentity().getSymbolicName();
resources.put(uniquekey, provider);
}
}
}
Resource getPrimary() {
return primary;
}
Collection<Resource> getResources() {
return Collections.unmodifiableCollection(resources.values());
}
boolean addDependencySpace(ResourceSpace dependency) {
if (dependency == null)
return false;
for (Resource aux : dependency.getResources()) {
String uniquekey = aux.getIdentity().getSymbolicName();
Resource other = resources.get(uniquekey);
if (other != null && other != aux) {
return false;
}
}
for (Resource aux : dependency.getResources()) {
String uniquekey = aux.getIdentity().getSymbolicName();
resources.put(uniquekey, aux);
}
return true;
}
@Override
public String toString() {
return "ResourceSpace[" + primary.getIdentity() + "]";
}
}
/**
* Provides an iterator over all possible wires for a given resource
*/
class ResourceCandidates {
private final Resource res;
private ResolutionException resolutionException;
ResourceCandidates(Resource res) {
this.res = res;
}
ResolutionException getResolutionException() {
return resolutionException;
}
Iterator<List<Wire>> iterator(final ResolveContext context) throws ResolutionException {
return new Iterator<List<Wire>>() {
private List<Iterator<Wire>> candidates = new ArrayList<Iterator<Wire>>();
private List<Requirement> reqs = res.getRequirements(null);
private Map<Requirement, Wire> wires;
private boolean hasNext;
@Override
public boolean hasNext() {
try {
if (wires == null) {
wires = new LinkedHashMap<Requirement, Wire>();
initWiremap(context, 0);
hasNext = true;
return true;
}
int index = reqs.size() - 1;
while (index >= 0) {
if (candidates.get(index).hasNext()) {
Wire wire = candidates.get(index).next();
Requirement req = wire.getRequirement();
wires.put(req, wire);
hasNext = true;
return true;
} else {
if (index > 0 && candidates.get(index - 1).hasNext()) {
initWiremap(context, index);
}
index--;
}
}
} catch (ResolutionException ex) {
resolutionException = ex;
}
hasNext = false;
return false;
}
private void initWiremap(final ResolveContext context, int start) throws ResolutionException {
for (int i = start; i < reqs.size(); i++) {
Requirement req = reqs.get(i);
RequirementCandidates reqcan = new RequirementCandidates(req);
Iterator<Wire> itcan = reqcan.iterator(context);
if (start == 0) {
candidates.add(itcan);
} else {
candidates.set(i, itcan);
}
if (itcan.hasNext()) {
wires.put(req, itcan.next());
}
}
}
@Override
public List<Wire> next() {
if (!hasNext)
throw new NoSuchElementException();
ArrayList<Wire> next = new ArrayList<Wire>(wires.values());
return Collections.unmodifiableList(next);
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
}
}
/**
* Provides an iterator over all possible wires for a given requirement
*/
class RequirementCandidates {
private final Requirement req;
RequirementCandidates(Requirement req) {
this.req = req;
}
Iterator<Wire> iterator(ResolveContext context) throws ResolutionException {
final Collection<Resource> optres = context.getOptionalResources();
final List<Capability> providers = context.findProviders(req);
// Fail early if there are no providers for a non-optional requirement
if (!optres.contains(req.getResource()) && !req.isOptional() && providers.isEmpty()) {
Set<Requirement> unresolved = Collections.singleton(req);
throw new ResolutionException("Cannot find provider for: " + req, null, unresolved);
}
return new Iterator<Wire>() {
Iterator<Capability> delagate = providers.iterator();
@Override
public boolean hasNext() {
return delagate.hasNext();
}
@Override
public Wire next() {
Capability cap = delagate.next();
return createWire(req, cap);
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
}
}
}