私はGoogleCaliperを使用して、文字列内のmdn番号をチェックする2つの方法をベンチマークします。1つのメソッドはユーザー定義のメソッドを使用しますが、他のメソッドは正規表現を使用します。平均して、正規表現メソッドはユーザー定義メソッドの5倍の時間がかかることに驚いています。
これが私のベンチマークコードです。
package com.code4refernce.caliper;
import java.util.Random;
import java.util.regex.Pattern;
import com.google.caliper.Param;
import com.google.caliper.SimpleBenchmark;
public class SimpleCaliperTest extends SimpleBenchmark {
String extensiveregex = "^\\d?(?:(?:[\\+]?(?:[\\d]{1,3}(?:[ ]+|[\\-.])))?[(]?(?:[\\d]{3})[\\-/)]?(?:[ ]+)?)?(?:[a-zA-Z2-9][a-zA-Z0-9 \\-.]{6,})(?:(?:[ ]+|[xX]|(i:ext[\\.]?)){1,2}(?:[\\d]{1,5}))?$";
Pattern EXTENSIVE_REGEX_PATTERN = Pattern.compile(extensiveregex);
String mdn[][];
Random random;
@Param
int index;
@Override
protected void setUp() {
random = new Random(0);
mdn = new String[11][1<<16];
for (int i=0; i<mdn.length; ++i) {
mdn[0][i] = String.format("%03ddsfasdf00000", random.nextInt(1000));
mdn[1][i] = String.format("%04d", random.nextInt(10000));
mdn[2][i] = String.format("%10d", random.nextInt((int) 1e10));
mdn[3][i] = String.format("-%10d", random.nextInt((int) 1e10));
mdn[4][i] = String.format("%10d-", random.nextInt((int) 1e10));
mdn[5][i] = String.format("%03d-%03d-%03d", random.nextInt(1000), random.nextInt(1000), random.nextInt(1000));
mdn[6][i] = String.format("-%03d-%03d-%03d-", random.nextInt(1000), random.nextInt(1000), random.nextInt(1000));
mdn[7][i] = String.format("%03d-%03d-%03d-", random.nextInt(1000), random.nextInt(1000), random.nextInt(1000));
mdn[8][i] = String.format("%03d-%03d-%03d ext %04d", random.nextInt(1000), random.nextInt(1000), random.nextInt(1000), random.nextInt(10000));
mdn[9][i] = String.format("%03d-%03d-%03d ext %04d-", random.nextInt(1000), random.nextInt(1000), random.nextInt(1000), random.nextInt(10000));
mdn[10][i] = "123456789012345677890";
}
}
/**
*This method benchmark the user defined method to check the mdn.
**/
public boolean timeExtensiveSimpleMDNCheck(int reps){
boolean results = false;
for(int i = 0; i<reps; i ++){
for(int index2=0; index2<mdn.length; index2++)
//Use simple method to check the phone number in string.
results ^= extensiveMDNCheckRegularMethod(mdn[index][index2]);
}
return results;
}
/**
*This method benchmark the regex method.
**/
public boolean timeExtensiveMDNRegexCheck(int reps){
boolean results = false;
for(int i = 0; i<reps; i ++){
for(int index2=0; index2<mdn.length; index2++)
//user Regular expression to check the phone number in string.
results ^=mdnExtensiveCheckRegEx(mdn[index][index2]);
}
return results;
}
public boolean extensiveMDNCheckRegularMethod(String mdn){
//Strip the character which not numeric or 'x' character.
String stripedmdn = stripString(mdn);
if(stripedmdn.length() >= 10 && stripedmdn.length() <= 11 && (!stripedmdn.contains("x") || !stripedmdn.contains("X"))){
//For following condition
//1-123-456-7868 or 123-456-7868
return true;
}else if ( stripedmdn.length() >= 15 && stripedmdn.length() <= 16 ) {
//1-123-456-7868 ext 2345 or 123-456-7868 ext 2345
//
if ( stripedmdn.contains("x") ) {
int index = stripedmdn.indexOf("x");
if(index >= 9 && index <= 10){
return true;
}
}else if( stripedmdn.contains("X") ) {
int index = stripedmdn.indexOf("X");
if(index >= 9 && index <= 10){
return true;
}
}
}
return false;
}
/**
* Strip the other character and leave only x and numeric values.
* @param extendedMdn
* @return
*/
public String stripString(String extendedMdn){
byte mdn[] = new byte[extendedMdn.length()];
int index = 0;
for(byte b : extendedMdn.getBytes()){
if((b >= '0' && b <='9') || b == 'x'){
mdn[index++] = b;
}
}
return new String(mdn);
}
private boolean mdnExtensiveCheckRegEx(String mdn){
return EXTENSIVE_REGEX_PATTERN.matcher(mdn).matches();
}
}
そして、ベンチマークを実行するメインクラス:
package com.code4refernce.caliper;
import com.google.caliper.Runner;
public class CaliperRunner {
public static void main(String[] args) {
String myargs[] = new String[1];
myargs[0] = new String("-Dindex=0,1,2,3,4,5,6,7,8,9,10");
Runner.main(SimpleCaliperTest.class, myargs);
}
}
そして、Caliperベンチマークの結果は次のとおりです。
Benchmark index us linear runtime
ExtensiveSimpleMDNCheck 0 5.44 =====
ExtensiveSimpleMDNCheck 1 4.34 ====
ExtensiveSimpleMDNCheck 2 5.02 =====
ExtensiveSimpleMDNCheck 3 5.08 =====
ExtensiveSimpleMDNCheck 4 4.92 ====
ExtensiveSimpleMDNCheck 5 4.83 ====
ExtensiveSimpleMDNCheck 6 4.87 ====
ExtensiveSimpleMDNCheck 7 4.72 ====
ExtensiveSimpleMDNCheck 8 5.14 =====
ExtensiveSimpleMDNCheck 9 5.25 =====
ExtensiveSimpleMDNCheck 10 5.57 =====
ExtensiveMDNRegexCheck 0 17.71 =================
ExtensiveMDNRegexCheck 1 21.73 =====================
ExtensiveMDNRegexCheck 2 13.47 =============
ExtensiveMDNRegexCheck 3 3.37 ===
ExtensiveMDNRegexCheck 4 12.44 ============
ExtensiveMDNRegexCheck 5 26.06 ==========================
ExtensiveMDNRegexCheck 6 3.36 ===
ExtensiveMDNRegexCheck 7 29.84 ==============================
ExtensiveMDNRegexCheck 8 23.80 =======================
ExtensiveMDNRegexCheck 9 24.01 ========================
ExtensiveMDNRegexCheck 10 20.53 ====================
ここで何かが足りませんか?正規表現の実行に時間がかかるのはなぜですか?