java Tracking changes inside a txt file

Question

I would like to ask if there any Java API which can fire events, when a specific line on the txt file change and which line is change, modified or delete? If not, I would like to point me the direction to look about it!

Thanks

http://stackoverflow.com/questions/494869/file-changed-listener-in-java — Zielu, Mar 22 '15 at 11:43

score 1 · Accepted Answer · answered Mar 22 '15 at 11:43

1

There is no such API in the Java standard library. The WatchService API allows you to detect when your .txt file is changed, but detecting which line is changed is something that you'll need to implement yourself.

In order to do that, you need to store the contents of the file as a list of lines, and when you receive a change notification, read the file again and compare the new contents with the contents you've previously stored.

answered Mar 22 '15 at 11:43

yole

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It good idea to have HashMap instead of list @yole??? – KostasC Mar 22 '15 at 14:50
If you don't care about the order of lines in your file and if it cannot contain duplicates, then yes, using a HashMap is a very good idea. – yole Mar 22 '15 at 14:51
I don't care about the order of lines but it cannot contain duplicates lines – KostasC Mar 22 '15 at 14:56
As I said, in this case a HashMap will work great. – yole Mar 22 '15 at 14:57

score 0 · Answer 2 · answered Mar 22 '15 at 11:43

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If you're targeting Linux, you can use the inotify system API. I know two Java projects to do that : - JNotify : http://jnotify.sourceforge.net/ - inotify-java : https://www.openhub.net/p/inotify-java

I hope this helped ;)

answered Mar 22 '15 at 11:43

mrgeek

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It seems that JNotify can also target Windows systems btw – mrgeek Mar 22 '15 at 11:44

java Tracking changes inside a txt file

2 Answers2