return replacements.get(sourceModule);
}
private static void detectCycles(Map<ModuleIdentifier, ModuleIdentifier> replacements, ModuleIdentifier source, ModuleIdentifier target) {
if (source.equals(target)) {
throw new InvalidUserDataException(String.format("Cannot declare module replacement that replaces self: %s->%s", source, target));
}
ModuleIdentifier m = replacements.get(target);
if (m == null) {
//target does not exist in the map, there's no cycle for sure
return;
}
Set<ModuleIdentifier> visited = new LinkedHashSet<ModuleIdentifier>();
visited.add(source);
visited.add(target);
while(m != null) {
if (!visited.add(m)) {
//module was already visited, there is a cycle
throw new InvalidUserDataException(
format("Cannot declare module replacement %s->%s because it introduces a cycle: %s",
source, target, Joiner.on("->").join(visited) + "->" + source));
}
m = replacements.get(m);
}