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Generic Evolver utility classes

There is a newer version: 3.5.0

package fi.evolver.utils.format;

import static fi.evolver.utils.NullSafetyUtils.denull;


public class FormatUtils {
	private static final char[] HEX_ARRAY = "0123456789ABCDEF".toCharArray();


	private FormatUtils() {}


	public static String truncate(String value, int maxLength) {
		if (value == null)
			return null;
		return value.length() <= maxLength ? value : value.substring(0, Math.max(maxLength, 0));
	}


	public static String truncatePretty(String value, int maxLength) {
		return truncatePretty(value, maxLength, "...", "?");
	}


	public static String truncatePretty(String value, int maxLength, String suffix, String defaultValue) {
		String result = denull(value, defaultValue);
		if (result == null)
			return null;

		if (result.length() > maxLength)
			result = truncate(truncate(value, maxLength - suffix.length()) + denull(suffix, "..."), maxLength);

		return result;
	}


	/**
	 * Safe String.format, which handles invalid arguments etc gracefully.
	 *
	 * @param message Base message.
	 * @param args Arguments for the message.
	 * @return Formatted result or null, if message was null.
	 */
	public static String format(String message, Object... args) {
		if (message == null)
			return null;
		if (args == null || args.length == 0)
			return message;

		try {
			return String.format(message, args);
		}
		catch (RuntimeException e) {
			return message + ": " + args;
		}
	}


	public static String toHex(byte[] bytes) {
	    char[] hexChars = new char[bytes.length * 2];
	    for (int j = 0; j < bytes.length; j++) {
	        int v = bytes[j] & 0xFF;
	        hexChars[j * 2] = HEX_ARRAY[v >>> 4];
	        hexChars[j * 2 + 1] = HEX_ARRAY[v & 0x0F];
	    }
	    return new String(hexChars);
	}


	public static String padLeft(String word, int length, char c) {
		if (word == null)
			return null;

		StringBuilder builder = new StringBuilder();
		for (int i = length - word.length(); i > 0; i--) {
			builder.append(c);
		}
		builder.append(word);
		return builder.toString();
	}

}