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package rd222dv_assign4.time;
import java.lang.System; //The class java.lang.System supports time measurements
public class Exercise2 {
private static int longStrLength = 80;
private static String longStr="";
public static void main(String[] args) {
for (int i = 0; i < longStrLength ; i++) {
longStr += "z";
}
for (int i = 0; i < 5; i++) {
stringOneCharacter();
string80Characters();
stringBuilderOneCharacter();
//stringBuilder80Character();
}
}
/*Java8 slide 40
Instant start = Instant.now();
doSomethingMethod();
Instant end = Instant.now();
Duration timeElapsed = Duration.between(start, end);
long millis = timeElapsed.toMillis();
*/
public static void stringOneCharacter() { //how many short strings can be added in one second
String string = ""; //initialize empty string
long before = System.currentTimeMillis();
while (System.currentTimeMillis() - before < 1000) { //run until 1second is reached
string = string + "z";
}
long after = System.currentTimeMillis();
int estimatedTime = (int) (after - before); //time in milliseconds, difference between before and after is the estimatedTime
System.out.println("Short String: Time: " + estimatedTime + " milliseconds. Concatenations: "
+ string.length() + ". Total length: " + string.length() + "\n");
}
public static void string80Characters() {
String string = "";
long before = System.currentTimeMillis();
while (System.currentTimeMillis() - before < 1000) {
string = string + longStr;
}
long after = System.currentTimeMillis();
int estimatedTime = (int) (after - before);
System.out.println("Long String: Time: " + estimatedTime + " milliseconds. Concatenations: "
+ (string.length() / 80) + ". Total length: " + string.length() + "\n");
}
public static void stringBuilderOneCharacter() {
StringBuilder str = new StringBuilder();
long before = System.currentTimeMillis();
while (System.currentTimeMillis() - before < 1000) {
str.append("a");
}
long after = System.currentTimeMillis();
int estimatedTime = (int) (after - before);
long start = System.currentTimeMillis();
str.toString();
long finish = System.currentTimeMillis();
int toStringTime = (int) (finish - start);
StringBuilder newBuilder = new StringBuilder();
long startPoint = System.currentTimeMillis();
while (System.currentTimeMillis() - startPoint < 1000 - toStringTime) {
newBuilder.append("a");
}
long endPoint = System.currentTimeMillis();
int newEstimatedTime = (int) (endPoint - startPoint);
System.out.println("Before ToString: Time: " + estimatedTime + " milliseconds." +
" Concatenations: " + str.length() + ". Total length: " + str.length());
System.out.println("ToString time: " + toStringTime + " milliseconds.");
System.out.println("After ToString: Time: " + (newEstimatedTime + toStringTime)
+ " milliseconds. Concatenations: " + newBuilder.length() + ". Total Length: "
+ newBuilder.length() + "\n");
}
public static void stringBuilder80Character() {
StringBuilder str = new StringBuilder();
long start = System.currentTimeMillis();
while (System.currentTimeMillis() - start < 1000) {
str.append(longStr);
}
long end = System.currentTimeMillis();
int estimatedTime = (int) (end - start);
long begin = System.currentTimeMillis();
str.toString();
long finish = System.currentTimeMillis();
int toStringTime = (int) (finish - begin);
StringBuilder newBuilder = new StringBuilder();
long startPoint = System.currentTimeMillis();
while (System.currentTimeMillis() - startPoint < 1000 - toStringTime) {
newBuilder.append(longStr);
}
long endPoint = System.currentTimeMillis();
int newEstimatedTime = (int) (endPoint - startPoint);
System.out.println("Before ToString: Time: " + estimatedTime + " milliseconds."
+ " Concatenations: " + str.length() + ". Total length: " + str.length());
System.out.println("ToString time: " + toStringTime + " milliseconds.");
System.out.println("After ToString: Time: " + (newEstimatedTime + toStringTime)
+ " milliseconds. Concatenation: " + (newBuilder.length() / 80) + ". Total Length: "
+ newBuilder.length() + "\n");
}
}
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