com.github.gimmi.Utils Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of any Show documentation
An immutable data structure that provide an uniform interface to map, list or scalar data
There is a newer version: 0.4.0
package com.github.gimmi;

class Utils {
	private static final int INDEX_NOT_FOUND = -1;
	private static final String EMPTY = "";

	public static String stripToEmpty(final String str) {
		return str == null ? EMPTY : strip(str, null);
	}

	public static String stripToNull(String str) {
		if (str == null) {
			return null;
		}
		str = strip(str, null);
		return str.isEmpty() ? null : str;
	}

	public static boolean toBoolean(final String str) {
		return toBooleanObject(str) == Boolean.TRUE;
	}

	private static Boolean toBooleanObject(final String str) {
		// Previously used equalsIgnoreCase, which was fast for interned 'true'.
		// Non interned 'true' matched 15 times slower.
		//
		// Optimisation provides same performance as before for interned 'true'.
		// Similar performance for null, 'false', and other strings not length 2/3/4.
		// 'true'/'TRUE' match 4 times slower, 'tRUE'/'True' 7 times slower.
		if (str == "true") {
			return Boolean.TRUE;
		}
		if (str == null) {
			return null;
		}
		switch (str.length()) {
			case 1: {
				final char ch0 = str.charAt(0);
				if (ch0 == 'y' || ch0 == 'Y' ||
						ch0 == 't' || ch0 == 'T') {
					return Boolean.TRUE;
				}
				if (ch0 == 'n' || ch0 == 'N' ||
						ch0 == 'f' || ch0 == 'F') {
					return Boolean.FALSE;
				}
				break;
			}
			case 2: {
				final char ch0 = str.charAt(0);
				final char ch1 = str.charAt(1);
				if ((ch0 == 'o' || ch0 == 'O') &&
						(ch1 == 'n' || ch1 == 'N') ) {
					return Boolean.TRUE;
				}
				if ((ch0 == 'n' || ch0 == 'N') &&
						(ch1 == 'o' || ch1 == 'O') ) {
					return Boolean.FALSE;
				}
				break;
			}
			case 3: {
				final char ch0 = str.charAt(0);
				final char ch1 = str.charAt(1);
				final char ch2 = str.charAt(2);
				if ((ch0 == 'y' || ch0 == 'Y') &&
						(ch1 == 'e' || ch1 == 'E') &&
						(ch2 == 's' || ch2 == 'S') ) {
					return Boolean.TRUE;
				}
				if ((ch0 == 'o' || ch0 == 'O') &&
						(ch1 == 'f' || ch1 == 'F') &&
						(ch2 == 'f' || ch2 == 'F') ) {
					return Boolean.FALSE;
				}
				break;
			}
			case 4: {
				final char ch0 = str.charAt(0);
				final char ch1 = str.charAt(1);
				final char ch2 = str.charAt(2);
				final char ch3 = str.charAt(3);
				if ((ch0 == 't' || ch0 == 'T') &&
						(ch1 == 'r' || ch1 == 'R') &&
						(ch2 == 'u' || ch2 == 'U') &&
						(ch3 == 'e' || ch3 == 'E') ) {
					return Boolean.TRUE;
				}
				break;
			}
			case 5: {
				final char ch0 = str.charAt(0);
				final char ch1 = str.charAt(1);
				final char ch2 = str.charAt(2);
				final char ch3 = str.charAt(3);
				final char ch4 = str.charAt(4);
				if ((ch0 == 'f' || ch0 == 'F') &&
						(ch1 == 'a' || ch1 == 'A') &&
						(ch2 == 'l' || ch2 == 'L') &&
						(ch3 == 's' || ch3 == 'S') &&
						(ch4 == 'e' || ch4 == 'E') ) {
					return Boolean.FALSE;
				}
				break;
			}
			default:
				break;
		}

		return null;
	}

	private static String strip(String str, final String stripChars) {
		if (isEmpty(str)) {
			return str;
		}
		str = stripStart(str, stripChars);
		return stripEnd(str, stripChars);
	}

	private static boolean isEmpty(final CharSequence cs) {
		return cs == null || cs.length() == 0;
	}

	private static String stripStart(final String str, final String stripChars) {
		int strLen;
		if (str == null || (strLen = str.length()) == 0) {
			return str;
		}
		int start = 0;
		if (stripChars == null) {
			while (start != strLen && Character.isWhitespace(str.charAt(start))) {
				start++;
			}
		} else if (stripChars.isEmpty()) {
			return str;
		} else {
			while (start != strLen && stripChars.indexOf(str.charAt(start)) != INDEX_NOT_FOUND) {
				start++;
			}
		}
		return str.substring(start);
	}

	private static String stripEnd(final String str, final String stripChars) {
		int end;
		if (str == null || (end = str.length()) == 0) {
			return str;
		}

		if (stripChars == null) {
			while (end != 0 && Character.isWhitespace(str.charAt(end - 1))) {
				end--;
			}
		} else if (stripChars.isEmpty()) {
			return str;
		} else {
			while (end != 0 && stripChars.indexOf(str.charAt(end - 1)) != INDEX_NOT_FOUND) {
				end--;
			}
		}
		return str.substring(0, end);
	}
}