I am trying to build an opensource text importer that will enable a user to import columnar non-delimited data from a flat file, make a guess at column boundaries, allow the user to adjust/change column boundaries visually, allow the user to specify field names and data types for columns, and allow the user to highlight and remove rows and columns they do not want imported. Then the data will be converted into a form suitable for use in a spreadsheet or database and saved in a new file.

In essence, I'm trying to build a simpler form of the MS Access/Excel "get external data" tool as a Java class/library. Conceptually, this doesn't seem that difficult. The biggest problem I have at the moment is the block separator lines contained in the data files. These files are a result of web based database dumps. Many times there are several header lines that identify the database and such, and then separator lines (usually time or geography markings) heading up each block of columnar data. There doesn't seem to be an easy way to distinguish columnar data from non-columnar data aside from processing a dozen lines or so to guess at column boundaries.

I'd rather not reinvent the wheel if you know of any opensource tools that can perform any of the functions I've mentioned. I'm also open to any suggestions regarding a direction to take in terms of design. I'm also looking for some suggestions regarding what package(s) to use to build the GUI.

Thanks in advance.