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StringTokeniszer, ArrayList and Exception demonstration
this example from a Well House Consultants training course
Source code: Zoe.java Module: J050
import java.io.*;
import java.util.*; /* Read in a web access log file and create objects ("Zoe"s) for each hit, which are then stored in an ArrayList. The constructor is called with a single String parameter - a web access log record - but unlike earlier examples in this series we're not simply saving the incoming parameter - we're actually unpacking it into 4 variables for later use. Although you may think "a constructor always returns an object", that's not necessarily the case ... for it can just throw an exception and return nothing at all. This is what it does in this case - if there's no valid data passed into the constructor, it can't create an object after all! */ public class Zoe { private String Host; private String Request; private String Time; private int status; public static void main (String [] args) throws IOException { ArrayList<Zoe> Visits = new ArrayList<Zoe>(); File Source = new File("access_log.xyz"); BufferedReader DataInput = new BufferedReader(new FileReader(Source)); int oopses = 0; while (true) { String stuff = DataInput.readLine(); if (stuff == null) break; try { Zoe wham = new Zoe(stuff); Visits.add(wham); } catch (Exception e) { oopses++; } } System.out.println ("Problems have I "+oopses); System.out.println ("Objects have I "+ Visits.size()); } public Zoe(String stuff) throws Exception{ try { StringTokenizer Chunk = new StringTokenizer(stuff," "); Host = Chunk.nextToken(); String skip = Chunk.nextToken(); skip = Chunk.nextToken("["); Time = Chunk.nextToken(" \t"); skip = Chunk.nextToken("\""); Request = Chunk.nextToken(); skip = Chunk.nextToken(" \t"); status = Integer.parseInt(Chunk.nextToken(" \t")); } catch (Exception e) { System.out.println("Short line"); throw e; } } } /* ------------------- Sample Output Dorothy-2:java grahamellis$ java Zoe Short line Short line Short line Short line Short line Short line Short line Short line Problems have I 8 Objects have I 6904 Dorothy-2:java grahamellis$ */ Learn about this subject
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