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@maxmalysh maxmalysh/Main.java
Last active Feb 16, 2017

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/*
Output:
100000 digits
3 ms | regex
9 ms | lambda
11 ms | StringUtils
1000000 digits
8 ms | regex
9 ms | lambda
2 ms | StringUtils
10000000 digits
128 ms | regex
56 ms | lambda
17 ms | StringUtils
100000000 digits
690 ms | regex
510 ms | lambda
161 ms | StringUtils
50M-long random string
599 ms | regex
248 ms | lambda
77 ms | StringUtils
*/
import org.apache.commons.lang3.RandomStringUtils;
import org.apache.commons.lang3.StringUtils;
import java.util.ArrayList;
import java.util.List;
public class Main {
public interface NumericChecker {
boolean isNumeric(String string);
}
public static class TestCase {
public String string;
public String name;
public TestCase(String string, String name) {
this.string = string;
this.name = name;
}
long runWith(NumericChecker checker) {
long startTime = System.nanoTime();
checker.isNumeric(string);
long stopTime = System.nanoTime();
return (stopTime - startTime) / 1000000;
}
}
public static NumericChecker regexChecker = new NumericChecker() {
private String regex = "\\d+";
@Override
public boolean isNumeric(String string) {
return string.matches(regex);
}
};
public static NumericChecker lamdaChecker = new NumericChecker() {
@Override
public boolean isNumeric(String string) {
return string.chars().allMatch(x -> Character.isDigit(x));
}
};
public static NumericChecker stringUtilsChecker = new NumericChecker() {
@Override
public boolean isNumeric(String string) {
return StringUtils.isNumeric(string);
}
};
public static void main(String[] args) {
int[] size = {100000, 1000000, 10000000, 100000000};
List<TestCase> tests = new ArrayList<>();
// Pure numbers
for (int N : size) {
String string = RandomStringUtils.randomNumeric(N);
tests.add(new TestCase(string, String.format("%s digits", N)));
}
// Not a number, adding just for the sake of diversity
String string = new StringBuilder().append(RandomStringUtils.randomNumeric(50000000))
.append("foobar")
.append(RandomStringUtils.randomNumeric(50000000))
.toString();
tests.add(new TestCase(string, "50M-long random string"));
// Warm-up JIT compiler
for (TestCase test : tests.subList(0, 1)) {
test.runWith(regexChecker);
test.runWith(lamdaChecker);
test.runWith(stringUtilsChecker);
}
for (TestCase test : tests) {
long runTimeRegex = test.runWith(regexChecker);
long runTimeLambda = test.runWith(lamdaChecker);
long runTimeStringUtils = test.runWith(stringUtilsChecker);
System.out.println(test.name);
System.out.printf("%6d ms | regex \n", runTimeRegex);
System.out.printf("%6d ms | lambda \n", runTimeLambda);
System.out.printf("%6d ms | StringUtils \n\n", runTimeStringUtils);
}
}
}
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