Java Utils - StringUtil

StringUtils.java

package com.zaccoding.util

public class StringUtil {
    public static boolean isEmpty(String value) {
        return (value == null) || (value.length() == 0);
    }

    public static boolean isNotEmpty(String value) {
        return (value != null) && (value.length() > 0);
    }
    
    public static boolean isBlank(String value) {
        int strLen;
        if (value == null || (strLen = value.length()) == 0) {
            return true;
        }

        for (int i = 0; i < strLen; i++) {
            if (!Character.isWhitespace(value.charAt(i))) {
                return false;
            }
        }

        return true;
    }

    public static String combineStrings(boolean threadSafe, String... values) {
        if (values == null || values.length == 0)
            return null;

        int totalLen = 0;
        for (String value : values) {
            totalLen += getStringLengthWith(value, 0);
        }
        if (threadSafe) {
            StringBuffer sb = new StringBuffer(totalLen);
            for (String value : values) {
                sb.append(value);
            }
            return sb.toString();
        }
        else {
            StringBuilder sb = new StringBuilder(totalLen);
            for (String value : values) {
                sb.append(value);
            }
            return sb.toString();
        }
    }

    public static int getStringLength(String value, int defaultLength) {
        if (value == null) {
            return defaultLength;
        }

        return value.length();
    }
    
    public static String convertHTML(String text) {
        final int initSize = text.length() * 2;
        StringBuilder sb = new StringBuilder(initSize);
        for (int i = 0; i < text.length(); i++) {
            char c = text.charAt(i);
            switch (c) {
                case '<':
                    sb.append("&lt;");
                    break;
                case '>':
                    sb.append("&gt;");
                    break;
                case '&':
                    sb.append("&amp;");
                    break;
                case '"':
                    sb.append("&quot;");
                    break;
                case '\'':
                    sb.append("&apos;");
                    break;
                default:
                    sb.append(c);
            }
        }
        return sb.toString();
    }
}