Re: ArrayIndexOutOfBoundsException confusion

From:
Lew <lew@nowhere.com>
Newsgroups:
comp.lang.java.help
Date:
Thu, 11 Jan 2007 23:21:30 -0500
Message-ID:
<Z_-dnbXPRLVWkTrYnZ2dnUVZ_oSnnZ2d@comcast.com>
phillip.s.powell wrote:

private final String[] buttonNameArray = {...};
private final String[] buttonValArray = {...};


It is hard in this type of situation to keep the arrays in synch with each
other. You could use a String [] [] to keep your pairs consistent, say,

private final String [] [] nameVals
   = {{ "cButton", "CE" }, { "ceButton", "%" }, ... };

 private Hashtable buttonHash = null;


You don't need to redundantly initialize instance variables to null.

Oh, and you might not need a Hashtable; a HashMap might serve your purposes.
It depends on multithreading and synchronization strategies.

   private Map< String, String> buttonMap = new HashMap< String, String> ();

private void initComponents() {

  this.buttonHash = new Hashtable();
  for (int i = 0; i < this.buttonNameArray.length; i++) {
    this.buttonHash.put(this.buttonNameArray[i],
this.buttonValArray[i]);
  }
}


   for ( String [] pair : nameVals )
   {
     buttonMap.put( pair [0], pair [1] );
   }

If you didn't control the array, you'd need to watch out for pair.length < 2.

A. Bolmarcich wrote:

The exception message is complaining an index value of 24 begin out of
bounds. What are the values of buttonNameArray.length and
buttonValArray.length?


With only one array, and a guarantee that each element thereof has two
elements, there is only one length to measure.

- Lew

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