TrimAllWhitespace Test. Spring StringUtils.trimAllWhitespace() is slow.

gistfile1.java

public class Test {
	static public String myTrimAllWhitespace(String str) {
		if (str != null) {
			int len = str.length();
			if (len > 0) {
				StringBuilder sb = new StringBuilder(len);
				for (int i = 0; i < len; ++i) {
					char c = str.charAt(i);
					if (!Character.isWhitespace(c)) {
						sb.append(c);
					}
				}
				return sb.toString();
			}
		}
		return str;
	}

	static public String myTrimAllWhitespace2(String str) {
		if (str != null) {
			int len = str.length();
			if (len > 0) {
				char[] dest = new char[len];
				int destPos = 0;
				for (int i = 0; i < len; ++i) {
					char c = str.charAt(i);
					if (!Character.isWhitespace(c)) {
						dest[destPos++] = c;
					}
				}
				return new String(dest, 0, destPos);
			}
		}
		return str;
	}
	
	static public String myTrimAllWhitespace3(String str) {
		if (str != null) {
			int len = str.length();
			if (len > 0) {
				char[] src = str.toCharArray();
				char[] dest = new char[src.length];

				int destPos = 0;
				for (int pos1 = 0, pos2 = 0; pos2 < src.length;) {
					if (Character.isWhitespace(src[pos2])) {
						if (pos1 == pos2) {
							pos1++;
							pos2++;
						} else {
							System.arraycopy(src, pos1, dest, destPos, pos2
									- pos1);
							destPos += (pos2 - pos1);
							pos2++;
							pos1 = pos2;
						}
					} else {
						pos2++;
					}

					if (pos2 == src.length) {
						if (pos1 != pos2) {
							System.arraycopy(src, pos1, dest, destPos, pos2
									- pos1);
							destPos += (pos2 - pos1);
						}
						return new String(dest, 0, destPos);
					}
				}
			}
		}
		return str;
	}

	public static boolean hasLength(CharSequence str) {
		return (str != null && str.length() > 0);
	}

	static public String myTrimAllWhitespaceUnicode(String str) {
		if (!hasLength(str)) {
			return str;
		}
		int pos = 0;
		int len = str.length();
		StringBuilder sb = new StringBuilder(len);
		while (pos < len) {
			int codePoint = Character.codePointAt(str, pos);
			char[] chars = Character.toChars(codePoint);
			if (!Character.isWhitespace(codePoint)) {
				sb.append(chars);
			}
			pos += chars.length;
		}
		return sb.toString();
	}

	public static void test() {
		String[] strArray = { "", "abc ", " x h z ", "   ", "  a", "a",
				"   a    ", "a ", " a", " ab cd ef kj ",
				"abc    edfg   oooo    ssss", "a a a a " };
		for (String string : strArray) {
			String trimAllWhitespace = org.springframework.util.StringUtils.trimAllWhitespace(string);
			if(!trimAllWhitespace.equals(myTrimAllWhitespace2(string)) 
					|| !trimAllWhitespace.equals(myTrimAllWhitespace3(string))
					|| !trimAllWhitespace.equals(myTrimAllWhitespaceUnicode(string))) {
				System.err.println(string);
				System.err.println("error!");
				System.exit(-1);
			}
		}
	}

	public static void main(String[] args) {
		test();
		String[] strArray = {
				"ab s df ff ds",
				"absdfffffffffffffffffffffffffffffffffffffffff sdfffffffffffffffffffffffffffffffffffffffffs",
				"a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a ",
		};
		
		int ttt = 0;
		for(String string : strArray) {
			for (int time = 0; time < 2; ++time) {
				System.out.println("----------------------");
				System.out.println("string: " + string);
				int count = 10000000;
				{
					long start = System.nanoTime();
					for (int i = 0; i < count; ++i) {
						String replaceBlank = org.springframework.util.StringUtils
								.trimAllWhitespace(string);
						if (replaceBlank.startsWith("X")) {
							ttt += 1;
						}
					}
					long end = System.nanoTime();
					System.out.println("trimAllWhitespace, time:\t" + (end - start) / 1000000.0);
				}

				{
					long start = System.nanoTime();
					for (int i = 0; i < count; ++i) {
						String replaceBlank = myTrimAllWhitespace(string);
						if (replaceBlank.startsWith("X")) {
							ttt += 1;
						}
					}
					long end = System.nanoTime();
					System.out.println("myTrimAllWhitespace time:\t" + (end - start) / 1000000.0);
				}

				{
					long start = System.nanoTime();
					for (int i = 0; i < count; ++i) {
						String replaceBlank = myTrimAllWhitespace2(string);
						if (replaceBlank.startsWith("X")) {
							ttt += 1;
						}
					}
					long end = System.nanoTime();
					System.out.println("myTrimAllWhitespace2 time:\t" + (end - start) / 1000000.0);
				}
				
				{
					long start = System.nanoTime();
					for (int i = 0; i < count; ++i) {
						String replaceBlank = myTrimAllWhitespace3(string);
						if (replaceBlank.startsWith("X")) {
							ttt += 1;
						}
					}
					long end = System.nanoTime();
					System.out.println("myTrimAllWhitespace3 time:\t" + (end - start) / 1000000.0);
				}
				
				{
					long start = System.nanoTime();
					for (int i = 0; i < count; ++i) {
						String replaceBlank = myTrimAllWhitespaceUnicode(string);
						if (replaceBlank.startsWith("X")) {
							ttt += 1;
						}
					}
					long end = System.nanoTime();
					System.out.println("myTrimAllWhitespaceUnicode time:\t" + (end - start) / 1000000.0);
				}
			}
		}
		
		System.out.println("ttt:" + ttt);
	}
}

---

string: ab s df ff ds
trimAllWhitespace, time: 1464.930011
myTrimAllWhitespace time: 931.668284
myTrimAllWhitespace2 time: 612.377962
myTrimAllWhitespace3 time: 1030.264558
myTrimAllWhitespaceUnicode time: 1718.113187

---

string: ab s df ff ds
trimAllWhitespace, time: 1286.266281
myTrimAllWhitespace time: 901.231429
myTrimAllWhitespace2 time: 620.1201
myTrimAllWhitespace3 time: 1089.587691
myTrimAllWhitespaceUnicode time: 1704.805074

---

string: absdfffffffffffffffffffffffffffffffffffffffff sdfffffffffffffffffffffffffffffffffffffffffs
trimAllWhitespace, time: 2426.387988
myTrimAllWhitespace time: 4370.659633
myTrimAllWhitespace2 time: 2193.304575
myTrimAllWhitespace3 time: 3124.781604
myTrimAllWhitespaceUnicode time: 11450.922751

---

string: absdfffffffffffffffffffffffffffffffffffffffff sdfffffffffffffffffffffffffffffffffffffffffs
trimAllWhitespace, time: 2435.480225
myTrimAllWhitespace time: 4359.093717
myTrimAllWhitespace2 time: 2259.316877
myTrimAllWhitespace3 time: 3122.034291
myTrimAllWhitespaceUnicode time: 11640.463152

---

string: a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
trimAllWhitespace, time: 17301.360847
myTrimAllWhitespace time: 6411.480031
myTrimAllWhitespace2 time: 3138.645121
myTrimAllWhitespace3 time: 10339.538524
myTrimAllWhitespaceUnicode time: 15667.220536

---

string: a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
trimAllWhitespace, time: 17401.499154
myTrimAllWhitespace time: 6504.075594
myTrimAllWhitespace2 time: 3161.379871
myTrimAllWhitespace3 time: 10442.165035
myTrimAllWhitespaceUnicode time: 15365.947787