Fast File Finder

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©1996-2012 Roedy Green, Canadian Mind Products

Please do not email me about this project without reading the disclaimer above.

Your task is to write a platform independent Fast File Find. I suggest you tackle it like this:

1. Create a SQL (Standard Query Language) database of all the filenames in the system.
2. Ask SQL to build three indexes, by directory name, by filename, and by extension.
3. When you get a request, analyse the wild card and convert it into a SQL query on those three fields. SQL will be clever and use its indexes or brute force if necessary. In any case it will always be faster than the Windows File Find since its database is contiguous. The directory that Windows searches can be scattered higgledy piggledy all over the disk.
4. If you don’t want to use SQL, you will need some sort of treemap/btree indexed file manager. Btrieve will let you package their product free with your apps, but that only covers Windows.
5. Allow copy to the clipboard of any result with a single click, as well as the traditional ways.
6. Allow launch of any of the result files with a double click, ideally support everything in the Windows right click menu for that file type.
7. Now for the hard part. How do you keep your SQL database up to date?
   • You could do it by brute force, just slowly and continuously scan through all the files on the disk looking for new, renamed or deleted ones. You don’t want to create so much I/O you become a pest. Then again you don’t want to dawdle so that you are too far out of date.
   • If you can persuade the OS (Operating System) to notify you of new, renamed or updated files, you can save considerable work. That hook would almost certainly require some JNI (Java Native Interface) code, or an independent auxiliary C program that sent you updates via TCP/IP (Transmission Control Protocol/Internet Protocol). You might check Filemon. They provide source for a VXD.

     There is a change-tracking facility built into Win2K, and Win2K also implements a find utility that’s based on an index (database) of the disk, using Microsoft Index Server (which comes bundled with Win2K). Windows 2000 now has a “fast find” built-in. It is hopelessly slow the way it grinds away for hours building indexes of file content that are always out of date.

     If you do hook into the OS for change notification, make sure you do your processing asynchronously. You don’t want to tie up the universe while you update your database. Just enqueue the work to be done later, so you don’t overload the system. Later when things aren’t so frantic you will eventually catch up.

8. Now you can get a little clever. You can do lazy updates of deleted files, procrastinating discovering and telling your SQL database about them. Don’t bother checking if the files exist until they show up in a result list of someone’s SQL query. Then at the last second check if the files still exist, and update the SQL database accordingly. You can also discover them with a low priority background process.
9. Of course you want something that at 3 AM refreshes the database and ensures it is not corrupt in any way and is 100% up-to-date.
10. For bonus points, in your displays, mark files that are in-use, or open-for-write. You can use File. canWrite or some platform specific code to find files that are being read too.
11. Consider a more elaborate user interface that looks something like this: Sorry, you need Java 1.1 or later to run this Applet.

    If, FF, the above FileFinder Java Applet does not work…

    1. Often problems can be fixed simply by clicking the reload button on your browser.
    2. Make sure you have both JavaScript and Java enabled in your browser.
    3. This Java Applet needs 32-bit (not 64-bit) Java 1.1 or later. For best results use the latest 1.7.0_02. If you have both 32 and 64-bit JVMs installed, in the Java Control Panel, configure your 32-bit java.exe as the user JVM and your 64-bit java.exe as the system JVM. You also need a recent browser.
    4. It works under any operating system that supports Java e.g. W2K/XP/W2003/Vista/W7-32/W7-64/Linux/OSX
    5. You should see the Applet above looking much like this screenshot. If you don’t, the following hints should help you get it working:
    6. Especially if this Applet has worked before, try clearing the browser cache and rebooting.
    7. To ensure your Java is up to date, check with Wassup. First, download it and run it as an application independent of your browser, then run it online as an Applet to add the complication of your browser.
    8. If the above Applet does not work, check the Java console for error messages.
    9. If the above Applet does not work, you might have better luck with the downloadable version available below.
    10. If you are using Microsoft Internet Explorer 7, 8 or 9, try another browser. Seriously. Microsoft has taken great pains, over and over, to screw up Java and every other multi-platform standardisation.
    11. If you are using Microsoft Internet Explorer 7, 8 or 9, you must click to allow blocked content permission for Active X to run. This also gives permission to Java to run. Click the Information bar, and then click Allow blocked content. Unfortunately, this also allows dangerous ActiveX code to run. However, you must do this in order to get access to perfectly-safe Java Applets running in a sandbox. This is part of Microsoft’s war on Java. Don’t put up with it! Use a different browser.
    12. If you are using Microsoft Internet Explorer 9, makes sure the Java Plug-In SSV helper add-in is installed and enabled. If it is not, try reinstalling the Java JRE.
    13. If you have Windows 7 64-bit and Internet Explorer 64-bit, in theory you can use 64-bit Java, but I never been able to get it to work.
    14. Try upgrading to a more recent version of your browser, or try a different browser e.g. Firefox, SeaMoney, Safari or Avant.
    15. If you still can’t get the program working click HELP for more detail.
    16. If you can’t get the above Applet working after trying the advice above and from the HELP button below, have bugs to report or ideas to improve the program or its documentation, please send me an email at.

       Get New Java  Get New Browser  

Why JNI?

The reasons I originally wanted to write a file find to replace Microsoft’s are:

1. I wanted it much faster.
2. I wanted it low overhead.
3. I wanted it up-to-date. I most often search for a file that I recently saved under the wrong name.

One nice thing about native classes is you can add more implementations later without disturbing existing code. JWS (Java Web Start) selects the right library for you.

FindCat

Desktop Google has provided a fast search, but by content, not by name.

	You can get the freshest copy of this page from:	or possibly from your local J: drive (Java virtual drive/mindprod.com website mirror)
	http://mindprod.com/project/filefinder.html	J:\mindprod\project\filefinder.html
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