Mercury

Mercury is a serious attempt to:

• Decouple major Maven components, making them available as stand-alone building blocks rather then having Maven as as one big monolith, not usable outside of its environment.
• Artifact - clearly separate an Artifact from its metadata.
• Repository - convert a repository into active component. It used to give back just pathOf(), now it accepts GAV collections and gives back either metadata or full blown Artifacts.
• Transport - an API in development.
• DependencyBuilder main API for dependency graph creation and conflict resolution.
• Decouple container, so that these components are just plain pojos. This is not necessarily good as wiring components together without a container complicates using the library.
• Introduce Jetty-based HTTP/HTTPS and WebDAV transactional transport layer.
• Asynchronous downloads and uploads. One of the few successful usages of Java NIO in OSS.
• Transactional operations - all-or-nothing for file sets.
• Move integrity control into transport layer, upper level components should not care about these details.
• Abstract out metadata cache, provide at least one implementation there.
• Integrate these changes back to Maven 3.x to make it even better platform than it is right now

Currently Mercury can already be used for accessing repositories, and conflict resolution/classpath calculation.