I've searched online for a solution and haven't found anything.
My problem is:
Have a game with lot of rooms. There's a chatroom inside of every room. I need to create a LOG of those rooms in different files with LOG4J.
I don't want to create an appender for every room that have been created. I need a automatically way to create a log file per room.
Is there any way to do that?
Log4J can create different log files for different classes using nothing but the log4j configuration file. If the rooms are instances of one or more classes, you'll have to handle it through your code. One possibility is to create a logger in the constructor and point it to a unique temp file so that each room that is constructed gets its own log file. I do not know how you make it easy to identify a room with a file other than forcing output as the first line. That might work but would still make it hard to identify the correct file just by the name. If the rooms have something unique about them you could try to use that as the log file name but without code from you I'd be guessing how you could do that.
Related
I have a task to implement a logging method that will take all program content up to logging method call and save it to file. The method should not overwrite already present info in file, but rather add new content to it.
What I need to write:
all program messages and output;
all user inputs in the way they appear on console (the program inquires it several times);
My thought on it is to create a StringBuilder object and start appending everything to it. Once logging method is invoked, ask for a file to save log to and save contents of StringBuilder to it. Then flush StringBuilder and continue to gather information. On second invocation, if the same filename is provided, just append new info gathered by StringBuilder.
However, this means that I will need to place gathering invocations all over the place where program output and user input are. Seems like not very optimal to me.
Are there any ideas on how to reach my goal differently and more optimally?
Thank you in advance.
Best regards,
Vadim
UPDATE: I actually was able to redirect system.out to gather everything to ByteArrayStream and then write to file on demand. But I still don't understand how to do it for inputstream. I don't need to redirect it, I still have to input eveyrthing from keyboard, it's just values that have to make it to logs in correct places. Am still searching for a solution.
Do not reinvent the wheel. Go for a logging framework. There is one integrated into java anyway.
Alternatively you can use log4j, and there are other such frameworks out there.
I'm working on a game and I am at that part that I want to save the game progress into a text file (or maybe a properties file would be good too), but I'd like to save that file to a place that is not reachable for the players. I was thinking about saving it to a source folder inside the program, but I am not able to save or load a text file from there, only images. Could anybody suggest something how/where to save the game stats that players can not just go into the settings file and modify their score or level or something like that?
With the properties file my only problem is the saving, where I need an output stream or a writer to save it, what I', not able to get
Assuming your player's pc has a regular hard drive with regular standards then:
If the game is offline(and maybe later synced with a server) then the answer is NO; if your app can access the file so does the user; even if you encrypt the data written to the save file people can just reverse engineer your app and get the keys and algorithms and modify the file; to put it simply you can only complicate it, their access to save files is inevitable.
If your game is only possible to be played online then you can do sanity check for every action of the players and save the progress in an inaccessible by players manner;
About the read only, been asked before:
create a read-only file
For the second one, keep in mind that as you know the path to the file and the name of it, the user don't. Saving the file using "scary" name, in un-trivial path will protect the file from any changes for a while
I want to store my blobs outside of the database in files, however they are just random blobs of data and aren't directly linked to a file.
So for example I have a table called Data with the following columns:
id
name
comments
...
I can't just include a column called fileLink or something like that because the blob is just raw data. I do however want to store it outside of the database. I would love to create a file called 3.dat where 3 is the id number for that row entry. The only thing with this setup is that the main folder will quickly start to have a large number of files as the id is a flat folder structure and there will be OS file issues. And no the data is not grouped or structured, it's one massive list.
Is there a Java framework or library that will allow me to store and manage the blobs so that I can just do something like MyBlobAPI.saveBlob(id, data); and then do MyBlobAPI.getBlob(id) and so on? In other words something where all the File IO is handled for me?
Simply use an appropriate database which implements blobs as you described, and use JDBC. You really are not looking for another API but a specific implementation. It's up to the DB to take care of effective storing of blobs.
I think a home rolled solution will include something like a fileLink column in your table and your api will create files on the first save and then write that file on update.
I don't know of any code base that will do this for you. There are a bunch that provide an in memory file system for java. But it's only a few lines of code to write something that writes and reads java objects to a file.
You'll have to handle any file system limitations yourself. Though I doubt you'll ever burn through the limitations of modern file systems like btrfs or zfs. FAT32 is limited to 65K files per directory. But even last generation file systems support something on the order of 4 billion files per directory.
So by all means, write a class with two functions. One to serialize an object to a file; given it a unique key as a name. And another to deserialize the object by that key. If you are using a modern file system, you'll never run out of resources.
As far as I can tell there is no framework for this. The closest I could find was Hadoop's HDFS.
That being said the advice of just putting the BLOB's into the database as per the answers below is not always advisable. Sometimes it's good and sometimes it's not, it really depends on your situation. Here are a few links to such discussions:
Storing Images in DB - Yea or Nay?
https://softwareengineering.stackexchange.com/questions/150669/is-it-a-bad-practice-to-store-large-files-10-mb-in-a-database
I did find some addition really good links but I can't remember them offhand. There was one in particular on StackOverFlow but I can't find it. If you believe you know the link please add it in the comments so that I can confirm it's the right one.
I have a requirement to include the name of the log file in the log entry itself.
For example say final name of the log file is something like trx_log.2014-09-22-12-42 the log entries I'm printing that log should have that same name. Following is a example log entry.
123456|test value|xyz|trx_log.2014-09-22-12-42
I'm using Log4j DailyRollingFileAppender to print the log at the moment. Is there a way which I can get this requirement implemented using some log4j/logback configuration.
Not that I'm aware of.
But a solution does exist nevertheless: write your own custom extension of the DailyRollingFileAppender.
Please note though the filename will be available to your custom appender only: in case you want to use such information in another appender (the only use case I can think of this might be of any use) then you need a more convoluted solution using a shared data storage (shared memory, file system, database, whatever) with the simplest solution being a static member of your just made appender. In this case the other appender (lat's say Console) need to be extended as well in order to append the new information to the log statement.
Use this method logger.getName()
logger.log(Level.SEVERE,"Exception in "+e.getMessage()+logger.getName());
I have a program that will write to a config.properties file with information that is shown in a separate .java form that is shown once you press a button.
The code to write that I current have is:
finally {
prop.setProperty("row0", textToWrite.replace(" ", "_").replace(":", "."));
}
// save properties to project root folder
prop.store(output, null);
Although once you set it, you need to close the program to see the change in the .properties file and therefore on the table inside the program.
I've tried searching for code that will refresh the file although with no luck.
EDIT:
As asked, a simple example would be this:
Properties file at the start:
Row0=Item1&&Item123;
Row1=Item2&&Item234;
Row2=Item3&&Item345;
The program will edit these so it should turn out like this:
Row0=NewItem&&NewItem2;
Row1=Item1&&Item123;
Row2=Item2&&Item234;
Although it only updates the file after the program is closed.
I am writing to a .properties file because it is a small amount of information that will be able to be read/edited without too much effort.
Most likely the cause of your problem is that you read properties file only at the start of your application. As you are changing the property file through code and want the other part of the code to see the properties change, so you need to introduce a properties file reload logic.
One way to do this is to move your properties file read logic in a separate method and call this method every time you make a change to the property file.
Other way could be using listeners, observers, etc.