Read Drosophila Genome

This source code is run in the example that reads the Drosophila genome and prints out the size of each chromosome:

```java import java.io.*; import java.util.*;

import org.biojava.bio.*; import org.biojava.bio.seq.*; import org.biojava.bio.seq.db.*; import org.biojava.bio.seq.io.*; import org.biojava.bio.symbol.*;

public class ReadFasta {

/**

• • The program takes two args: the first is the file name of the Fasta file.
• • The second is the name of the Alphabet. Acceptable names are DNA RNA or PROTEIN.
  • /

public static void main(String[] args) {

  try {
    //setup file input
    String filename = args[0];
    BufferedInputStream is =
      new BufferedInputStream(new FileInputStream(filename));

    //get the appropriate Alphabet
    Alphabet alpha = AlphabetManager.alphabetForName(args[1]);

    //get a SequenceDB of all sequences in the file
    SequenceDB db = SeqIOTools.readFasta(is, alpha);

    //list sequences and length
    SequenceIterator sI = db.sequenceIterator();
    long total = 0;
    while (sI.hasNext()) {
      Sequence seq = sI.nextSequence();
      System.out.println(seq.getName() + "\t" + seq.length());
      total += seq.length();
    }
    System.out.println("Total length is " + total);
  }
  catch (BioException ex) {
    //not in fasta format or wrong alphabet
  }catch (NoSuchElementException ex) {
    //no fasta sequences in the file
    ex.printStackTrace();
  }catch (FileNotFoundException ex) {
    //problem reading file
    ex.printStackTrace();
  }
}

} ```