Re: How to cast an Object to Double?

From:

Lew <lew@lewscanon.com>

Newsgroups:

comp.lang.java.programmer

Date:

Wed, 17 Oct 2007 19:35:55 -0400

Message-ID:

<f8WdnQ9VL73BAYvanZ2dnUVZ_gWdnZ2d@comcast.com>

RedGrittyBrick wrote:

Maybe this makes it clearer ...

public class PropertyDouble {
  public static void main(String[] args)
      throws FileNotFoundException, IOException {

    Properties states = new Properties();
    states.load(new FileInputStream("property_file.txt"));

One would be safer using a FileReader.

// copy entries from states file to the map

Since you already pointed out:

I'm not sure why you are copying a HashTable backed Properties object into a new HashMap.
Surely you could just use "states" where you later use "map"?

we could skip that copy. (It's actually a mistake Sun made having Properties
extend Hashtable.) I know you show it in order to make the points about
conversion, but let's take a look at what life is like without the copy:

Continuing the code snippet:

    double value = 2.54 * Double.parseDouble( states.getProperty( "HAT_SIZE" ));
    System.out.printf("Metric : %.4f \n", value);
  }
}

--
Lew