/** @return The module version, or null if there is a failure to resolve this selector. */
public ModuleVersionResolveState resolveModuleRevisionId() {
if (targetModuleRevision != null) {
return targetModuleRevision;
}
if (failure != null) {
return null;
}
idResolveResult = new DefaultBuildableComponentIdResolveResult();
resolver.resolve(dependencyMetaData, idResolveResult);
if (idResolveResult.getFailure() != null) {
failure = idResolveResult.getFailure();
return null;
}
targetModuleRevision = resolveState.getRevision(idResolveResult.getModuleVersionId());
targetModuleRevision.addResolver(this);
targetModuleRevision.selectionReason = idResolveResult.getSelectionReason();
targetModule = targetModuleRevision.module;
targetModule.addSelector(this);
return targetModuleRevision;
}
/**
* Traverses the dependency graph, resolving conflicts and building the paths from the root
* configuration.
*/
private void traverseGraph(
final ResolveState resolveState, final ConflictHandler conflictHandler) {
resolveState.onMoreSelected(resolveState.root);
List<DependencyEdge> dependencies = new ArrayList<DependencyEdge>();
while (resolveState.peek() != null || conflictHandler.hasConflicts()) {
if (resolveState.peek() != null) {
ConfigurationNode node = resolveState.pop();
LOGGER.debug("Visiting configuration {}.", node);
// Calculate the outgoing edges of this configuration
dependencies.clear();
node.visitOutgoingDependencies(dependencies);
for (DependencyEdge dependency : dependencies) {
LOGGER.debug("Visiting dependency {}", dependency);
// Resolve dependency to a particular revision
ModuleVersionResolveState moduleRevision = dependency.resolveModuleRevisionId();
if (moduleRevision == null) {
// Failed to resolve.
continue;
}
ModuleIdentifier moduleId = moduleRevision.id.getModule();
// Check for a new conflict
if (moduleRevision.state == ModuleState.New) {
ModuleResolveState module = resolveState.getModule(moduleId);
// A new module revision. Check for conflict
PotentialConflict c = conflictHandler.registerModule(module);
if (!c.conflictExists()) {
// No conflict. Select it for now
LOGGER.debug("Selecting new module version {}", moduleRevision);
module.select(moduleRevision);
} else {
// We have a conflict
LOGGER.debug("Found new conflicting module version {}", moduleRevision);
// Deselect the currently selected version, and remove all outgoing edges from the
// version
// This will propagate through the graph and prune configurations that are no longer
// required
// For each module participating in the conflict (many times there is only one
// participating module that has multiple versions)
c.withParticipatingModules(
new Action<ModuleIdentifier>() {
public void execute(ModuleIdentifier module) {
ModuleVersionResolveState previouslySelected =
resolveState.getModule(module).clearSelection();
if (previouslySelected != null) {
for (ConfigurationNode configuration : previouslySelected.configurations) {
configuration.deselect();
}
}
}
});
}
}
dependency.attachToTargetConfigurations();
}
} else {
// We have some batched up conflicts. Resolve the first, and continue traversing the graph
conflictHandler.resolveNextConflict(
new Action<ConflictResolutionResult>() {
public void execute(final ConflictResolutionResult result) {
result
.getConflict()
.withParticipatingModules(
new Action<ModuleIdentifier>() {
public void execute(ModuleIdentifier moduleIdentifier) {
ModuleVersionResolveState selected = result.getSelected();
// Restart each configuration. For the evicted configuration, this means
// moving incoming dependencies across to the
// matching selected configuration. For the select configuration, this
// mean traversing its dependencies.
resolveState.getModule(moduleIdentifier).restart(selected);
}
});
}
});
}
}
}