CODEWITHSUNDEEP
javaperformance
WannabeCoder
WannabeCoder

Reputation: 498

Storing Large Amounts of Dictionary-Like Data Within an Application in Java

I fear I may not be truly understanding the utility of database software like MySQL, so perhaps this is an easy question to answer.

I'm writing a program that stores and accesses a bestiary for use in the program. It is a stand-alone application, meaning that it will not connect to the internet or a database (which I am under the impression requires a connection to a server). Currently, I have an enormous .txt file that it parses via a simple pattern (Habitat is on every tenth line, starting with the seventh; name is on every tenth line, starting with the first; etc.) This is prone to parsing errors (problems with reading data that is unrecognizable with the specified encoding, as a lot of the data is copy/pasted by lazy data-entry-ists) and I just feel that parsing a giant .txt file every time I want data is horribly inefficient. Plus, I've never seen a deployed program that had a .txt laying around called "All of our important data.txt".

Are databases the answer? Can they be used simply in basic applications like this one? Writing a class for each animal seems silly. I've heard XML can help, too - but I know virtually nothing about it except that its a mark-up language.

In summary, I just don't know how to store large amounts of data within an application. A good analogy would be: How would you store data for a dictionary/encyclopedia application?

Upvotes: 0

Views: 531

Answers (2)

user206428
user206428

Reputation:

While databases are undoubtedly a good idea for the kind of application you're describing, I'll throw another suggestion your way, which might suit you if your data doesn't necessarily need to change at all, and there's not a "huge" amount of it.

Java provides the ability to serialise objects, which you could use to persist and retrieve object instance data directly to/from files. Using this simple approach, you could:

  • Write code to parse your text file into a collection of serialisable application-specific object instances;
  • Serialise these instances to some file(s) which form part of your application;
  • De-serialise the objects into memory every time the application is run;
  • Write your own Java code to search and retrieve data from these objects yourself, for example using ordered collection structures with custom comparators.

This approach may suffice if you:

  • Don't expect your data to change;
  • Do expect it to always fit within memory on the JVMs you're expecting the application will be run on;
  • Don't require sophisticated querying abilities.

Even if one or more of the above things do not hold, it may still suit you to try this approach, so that your next step could be to use a so-called object-relational mapping tool like Hibernate or Castor to persist your serialisable data not in a file, but a database (XML or relational). From there, you can use the power of some database to maintain and query your data.

Upvotes: 0

Srihari
Srihari

Reputation: 766

So you are saying that a standalone application without internet access cannot have a database connection? Well your Basic assumption that DB cannot exist in standalone apps is wrong. Today's web applications use Browser assisted SQL databases to store data. All you need is to experiment rather than speculate. If you need direction, start with light weight SQLite

Upvotes: 3

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