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Thread: Arraylists

  1. #1
    talia is offline Member
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    Default Arraylists

    Hi I need some help with arraylists, I am trying to load a text file into an array list with the following method:

    Java Code:
    public static ArrayList LoadFile(JTextArea src){
            String line = "";
            ArrayList data = new ArrayList();
            try{
                FileReader fr = new FileReader("Products.txt");
                BufferedReader br = new BufferedReader(fr);
                while ((line = br.readLine()) != null){
                    
                 src.append(line);
                    src.append(System.getProperty("line.separator"));
               } 
            }catch(FileNotFoundException fN) {
                    fN.printStackTrace();
                }
            catch(IOException e){
                System.out.println(e);
            }
            return data;
    I use netbeans, and have to make things work with a GUI. I can display the contents of this file in a JTextArea by pressing a Display button. What I would like to know is how to proceed from here. I want to be able to search the arraylist for a particular word when typed in the GUI and then display it. How is this possible. I have spent hours to figure this out so far and couldnt come up with a solution.
    Also the above arraylist is defined in a class, while the search and display is done in the MainFrame class.

    Hope some one can show me to the right direction.

    thanks
    Last edited by JosAH; 01-30-2012 at 05:57 PM. Reason: added [code] ... [/code] tags

  2. #2
    christopherx is offline Member
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    Default Re: Arraylists

    Well splitting it up into lines and placing it into the textarea is all well and good for displaying it. For searching through it I would highly reccomend concatenating it all into a string, and using the String API to help you find the method for looking for certain patterns. For looking for certain patterns in strings, I would HIGHLY recommend teaching yourself regular expressions :)

  3. #3
    JosAH's Avatar
    JosAH is offline Moderator
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    Default Re: Arraylists

    A List has an indexOf( ... ) method; it searches the list and if an element is found, its index is returned (otherwise -1 is returned). Read the API documentation for the List interface.

    kind regards,

    Jos
    The only person who got everything done by Friday was Robinson Crusoe.

  4. #4
    christopherx is offline Member
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    Default Re: Arraylists

    Quote Originally Posted by JosAH View Post
    A List has an indexOf( ... ) method; it searches the list and if an element is found, its index is returned (otherwise -1 is returned). Read the API documentation for the List interface.

    kind regards,

    Jos
    I think using the indexOf() method assumes that the pattern will match the whole line, which isn't always the case.

  5. #5
    JosAH's Avatar
    JosAH is offline Moderator
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    Default Re: Arraylists

    Quote Originally Posted by christopherx View Post
    I think using the indexOf() method assumes that the pattern will match the whole line, which isn't always the case.
    True, but then maybe a list of lines of text isn't the ideal data structure to solve the problem ...

    kind regards,

    Jos
    The only person who got everything done by Friday was Robinson Crusoe.

  6. #6
    talia is offline Member
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    Default Re: Arraylists

    Thanks, for your replies I will now have a look at all the recommended documentation and hopefully can solve this:)
    cheers....

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