package examples;

import org.apache.log4j.PropertyConfigurator;
import org.apache.log4j.Logger;
import org.apache.log4j.Priority;  

/**
   Example code for log4j to viewed in conjunction with the {@link
   examples.SortAlgo SortAlgo} class.
   
   
This program expects a configuration file name as its first
   argument, and the size of the array to sort as the second and last
   argument. See its source
   code for more details.

   
Play around with different values in the configuration file and
   watch the changing behavior.

   
Example configuration files can be found in sort1.properties, sort2.properties, sort3.properties and sort4.properties are supplied with the
   package.
   
   
If you are also interested in logging performance, then have
   look at the {@link org.apache.log4j.performance.Logging} class.

   @author Ceki Gülcü */

public class Sort {

  static Logger logger = Logger.getLogger(Sort.class.getName());
  
  public static void main(String[] args) {
    if(args.length != 2) {
      usage("Incorrect number of parameters.");
    }
    int arraySize = -1;
    try {
      arraySize = Integer.valueOf(args[1]).intValue();
      if(arraySize <= 0) 
	usage("Negative array size.");
    }
    catch(java.lang.NumberFormatException e) {
      usage("Could not number format ["+args[1]+"].");
    }

    PropertyConfigurator.configure(args[0]);

    int[] intArray = new int[arraySize];

    logger.info("Populating an array of " + arraySize + " elements in" +
	     " reverse order.");
    for(int i = arraySize -1 ; i >= 0; i--) {
      intArray[i] = arraySize - i - 1;
    }

    SortAlgo sa1 = new SortAlgo(intArray);
    sa1.bubbleSort();
    sa1.dump();

    // We intentionally initilize sa2 with null.
    SortAlgo sa2 = new SortAlgo(null);
    logger.info("The next log statement should be an error message.");
    sa2.dump();  
    logger.info("Exiting main method.");    
  }
  
  static
  void usage(String errMsg) {
    System.err.println(errMsg);
    System.err.println("\nUsage: java org.apache.examples.Sort " +
		       "configFile ARRAY_SIZE\n"+
      "where  configFile is a configuration file\n"+
      "      ARRAY_SIZE is a positive integer.\n");
    System.exit(1);
  }
}