[ale] OT: java filereader question

[Denny Chambers]

BTW, the reason it working in main, is because main say it will throw 
java.io.IOException, so you are not required to do the try/catch if your 
going to throw it up a layer. You have also add the "throws 
java.io.IOException" clause to doMergeSort and everything would have 
been fine.

Denny Chambers wrote:

> ahh ok i see
>
> try{
> FileReader fr = new FileReader("file1");
> }
> catch(FileNotFoundException fnfe){
> //handle exception
> }
>
>
>
>
>
> J.M. Taylor wrote:
>
>> Sun's 1.4.1_02, and your suggestion is *exactly* what I'm trying.  I 
>> even backed off and just tried to do
>> FileReader fr = new FileReader("file1");
>>
>> and then I took out *all* of my code except where I instantiate the 
>> FileReader inside the method...still I'm getting:
>> unreported exception java.io.FileNotFoundException; must be caught or 
>> declared to be thrown
>>      FileReader fr = new FileReader("file1");
>>                      ^
>>
>> This is the skeleton of the code I'm using...FileReader works fine 
>> inside of main...there is definitely something major I'm missing here...
>> -----
>> import java.util.*;
>> import java.io.*;
>>
>> public class mergesort
>> {
>>  public static void main(String[] args) throws java.io.IOException
>>  {
>>    /*--snip---*/
>>    doMergeSort(1,0,100);
>>  }
>>
>>  public static void doMergeSort(int blsize, int fileset, double 
>> filesize)
>>  {
>>    if (blocksize < filesize/4)
>>    {
>>      FileReader fr = new FileReader("file1");     }
>>  }
>> }
>>
>> Thanks very much for looking at this...I'm afraid Java is still more 
>> than a little bit of black magic to me right now.
>>
>> jenn
>>
>>
>>
>> On Thu, 8 Apr 2004, Denny Chambers wrote:
>>
>>  
>>
>>> First, what version of java are you using? (java -version)
>>>
>>> If you using Sun/IBM/Blackdown versions 1.1 or later, then this 
>>> should work:
>>>
>>> String filename = (conditional ? "file1" : "file2");
>>> FileReader fr = new FileReader(filename);
>>>
>>> Now file1 and file2 should be a string representation of the 
>>> relative or absolute path the files in question
>>>
>>> FileReader has a constructor FileReader(String fileName)
>>>
>>>
>>> Denny
>>>
>>>
>>>
>>> J.M. Taylor wrote:
>>>
>>>   
>>>
>>>> Greetings all,
>>>>
>>>> I need to evaluate a condition and decide whether to open file1 or 
>>>> file2 based on that condition.  Obviously I can do
>>>> if (conditional) {
>>>> FileReader fr = new FileReader("file1");
>>>> }
>>>> else {
>>>> FileReader fr = new FileReader("file2");
>>>> }
>>>>
>>>> However, with my undisciplined scripting language background I 
>>>> would like to do something like
>>>>
>>>> File filename = (conditional ? "file1" : "file2");
>>>> FileReader fr = new FileReader(filename);
>>>>
>>>> I can do the ternary operator if I declare filename as a String, 
>>>> but then FileReader won't open it (the parameter must be a File 
>>>> object). new FileReader((File)filename) doesn't work either.
>>>>
>>>> Nor does FileReader fr = (conditional ? new FileReader("file1") : 
>>>> new FileReader("file2"));
>>>>
>>>> Nor does FileReader fr = new FileReader((conditional ? "file1" : 
>>>> "file2"));
>>>> I don't use Java very much, but I like to understand what's going 
>>>> on (and why I can and can't do things from language to language) as 
>>>> much as possible.  If anybody out there in aleland uses Java and 
>>>> can help me out, I would greatly appreciate it.  I won't be 
>>>> offended if you tell me why I'm being brain-dead, if that is in 
>>>> fact the case.
>>>>
>>>> Thanks
>>>> jenn
>>>>
>>>>
>>>>
>>>>     
>>>
>>
>>  
>>
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