How can I monitor a folder with Cocoa?

I want to create a Cocoa application to monitor a folder for new files on Mac OS X. I know I can do this using AppleScript and Folder Actions, but how can I use ObjC and Cocoa for 开发者_JAVA百科that?

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Have a look at File System Events

Although, for really fine-grained monitoring the documentation points to using kqueues