Counts how many times the substring appears in the larger String.
* *A null
or empty ("") String input returns 0
.
* StringUtils.countMatches(null, *) = 0 * StringUtils.countMatches("", *) = 0 * StringUtils.countMatches("abba", null) = 0 * StringUtils.countMatches("abba", "") = 0 * StringUtils.countMatches("abba", "a") = 2 * StringUtils.countMatches("abba", "ab") = 1 * StringUtils.countMatches("abba", "xxx") = 0 ** * @param str the String to check, may be null * @param sub the substring to count, may be null * @return the number of occurrences, 0 if either String is
null
*/
public static int countMatches(String str, String sub) {
if (isEmpty(str) || isEmpty(sub)) {
return 0;
}
int count = 0;
int idx = 0;
while ((idx = str.indexOf(sub, idx)) != -1) {
count++;
idx += sub.length();
}
return count;
}
// Empty checks
//-----------------------------------------------------------------------
/**
* Checks if a String is empty ("") or null.
* ** StringUtils.isEmpty(null) = true * StringUtils.isEmpty("") = true * StringUtils.isEmpty(" ") = false * StringUtils.isEmpty("bob") = false * StringUtils.isEmpty(" bob ") = false ** *
NOTE: This method changed in Lang version 2.0. * It no longer trims the String. * That functionality is available in isBlank().
* * @param str the String to check, may be null * @returntrue
if the String is empty or null
*/
public static boolean isEmpty(String str) {
return str == null || str.length() == 0;
}
}