We already have aPmdAnalysis class that serves as a programatic (non-CLI) entry point for PMD. This allows, the CLI, ANT, IDEs and other tools to trigger an analysis in an agnostic way.

We don't have anything equivalent for CPD, with theCPD,CPDConfiguration andCPDCommandLineInterface all mingled and dirty with CLI specific things (ie: theCPDConfiguration actually has the JCommander annotations).

What we would need to do:

• Explicitly convertCPDConfiguration into a pure "analysis configuration" class, equivalent toPMDConfiguration. Is there anyway to "deprecate" the annotations in PMD 6 beyond a javadoc notice?
• Consolidate how PMD / CPD collect analysis files
  • Since we are aligning how PMD / CPD manage analysis sources, it may make sense to pull up those attributes and methods toAbstractConfiguration
  • ExtendFileCollector to accept any kind of configuration, either for PMD or CPD
    • Tricky part:FileCollector depends onLanguageDiscoverer which is PMD-specific (CPD and PMD Language classes are unrelated), CPD on the other hand uses aFileExtensionFilter).
• Implement aCpdAnalysis class in the same shape asPmdAnalysis. There may be an opportunity here to have a shared interface, but I'm not sure if this would be worth it.
• HookCpdAnalysis intoCPD to retain behavior, and explicitly stateCpdAnalysis to be the replacement for the already deprecatedCPD.

I've a local branch where I've already started working on some of these items.