org.apache.log4j.performance: public class: ConcatVsArray

org.apache.log4j.performance
public class: ConcatVsArray [javadoc | source]

java.lang.Object
   org.apache.log4j.performance.ConcatVsArray

Measure difference in performance of string concatenation versus creating an anonymous string array.

You should be able to see that anonymous string array construction is significatnly faster than string concatenation. The difference increases proportionally with the length of the strings to be concatanated.

author: Ceki - Gülcü

Method from org.apache.log4j.performance.ConcatVsArray Summary:
Usage, main

Methods from java.lang.Object:
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from org.apache.log4j.performance.ConcatVsArray Detail:
static void Usage() { System.err.println("Usage: java org.apache.log4j.performance.ConcatVsArray " + "string1 string2 runLength\n" + " where runLength is an integer."); System.exit(1); }
public static void main(String[] args) { if(args.length != 3) { Usage(); } String s1 = args[0]; String s2 = args[1]; int runLength = 0; try { runLength = Integer.parseInt(args[2]); } catch(java.lang.NumberFormatException e) { System.err.println(e); Usage(); } double micros; String[] sa; long before = new Date().getTime(); for(int i = 0; i < runLength; i++) { sa = new String[]{s1, s2}; } micros = (new Date().getTime() - before)1000.0/runLength; System.out.println("The anonymous array loop took around " + micros + " microseconds."); String s; before = new Date().getTime(); for(int i = 0; i < runLength; i++) { s = s1 + s2; } micros = (new Date().getTime() - before)1000.0/runLength; System.out.println("The append loop took around " + micros + " microseconds."); }

Method from org.apache.log4j.performance.ConcatVsArray Detail:

 static  void Usage() {
    System.err.println("Usage: java org.apache.log4j.performance.ConcatVsArray " +
		       "string1 string2 runLength\n" +
		       "       where runLength is an integer.");
    System.exit(1);
}

 public static  void main(String[] args) {
    if(args.length != 3) {
      Usage();
    }    
    String s1 = args[0];
    String s2 = args[1];
    int runLength = 0;
    try {
      runLength = Integer.parseInt(args[2]);      
    }
    catch(java.lang.NumberFormatException e) {
      System.err.println(e);
      Usage();
    }      
    double micros;
    String[] sa;
    long before = new Date().getTime();
    for(int i = 0; i <  runLength; i++) {
      sa = new String[]{s1, s2};
    }
    micros = (new Date().getTime() - before)*1000.0/runLength;
    System.out.println("The anonymous array loop took around " + micros + " microseconds.");
    String s;    
    before = new Date().getTime();
    for(int i = 0; i <  runLength; i++) {
      s = s1 + s2;
    }
    micros = (new Date().getTime() - before)*1000.0/runLength;
    System.out.println("The append loop took around " + micros + " microseconds.");
}