examples/src/sort/Sort.java

/*
 * Copyright 1999,2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package sort;

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


/**
   Example code for log4j to viewed in conjunction with the {@link
   examples.SortAlgo SortAlgo} class.

   <p>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 <b><a href="doc-files/Sort.java">source
   code</a></b> for more details.

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

   <p>Example configuration files can be found in <a
   href="doc-files/sort1.properties">sort1.properties</a>, <a
   href="doc-files/sort2.properties">sort2.properties</a>, <a
   href="doc-files/sort3.properties">sort3.properties</a> and <a
   href="doc-files/sort4.properties">sort4.properties</a> are supplied with the
   package.

   <p>If you are also interested in logging performance, then have
   look at the {@link org.apache.log4j.performance.Logging} class.

   @author Ceki G&uuml;lc&uuml; */
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);
  }
}