@CheckReturnValue @GwtCompatible public final class Strings extends Object
Static utility methods pertaining to String or CharSequence instances.
| Modifier and Type | Method and Description |
|---|---|
static String |
commonPrefix(CharSequence a,
CharSequence b)
Returns the longest string
prefix such that a.toString().startsWith(prefix) && b.toString().startsWith(prefix), taking care not to split surrogate pairs. |
static String |
commonSuffix(CharSequence a,
CharSequence b)
Returns the longest string
suffix such that a.toString().endsWith(suffix) && b.toString().endsWith(suffix), taking care not to split surrogate pairs. |
static String |
emptyToNull(String string)
Returns the given string if it is nonempty;
null otherwise. |
static boolean |
isNullOrEmpty(String string)
Returns
true if the given string is null or is the empty string. |
static String |
nullToEmpty(String string)
Returns the given string if it is non-null; the empty string otherwise.
|
static String |
padEnd(String string,
int minLength,
char padChar)
Returns a string, of length at least
minLength, consisting of string appended with as many copies of padChar as are necessary to reach that length. |
static String |
padStart(String string,
int minLength,
char padChar)
Returns a string, of length at least
minLength, consisting of string prepended with as many copies of padChar as are necessary to reach that length. |
static String |
repeat(String string,
int count)
Returns a string consisting of a specific number of concatenated copies of an input string.
|
public static String nullToEmpty(@Nullable String string)
Returns the given string if it is non-null; the empty string otherwise.
string - the string to test and possibly returnstring itself if it is non-null; "" if it is null@Nullable public static String emptyToNull(@Nullable String string)
Returns the given string if it is nonempty; null otherwise.
string - the string to test and possibly returnstring itself if it is nonempty; null if it is empty or nullpublic static boolean isNullOrEmpty(@Nullable String string)
Returns true if the given string is null or is the empty string.
Consider normalizing your string references with nullToEmpty(java.lang.String). If you do, you can use String.isEmpty() instead of this method, and you won’t need special null-safe forms of methods like String.toUpperCase(java.util.Locale) either. Or, if you’d like to normalize “in the other direction,” converting empty strings to null, you can use emptyToNull(java.lang.String).
string - a string reference to checktrue if the string is null or is the empty stringpublic static String padStart(String string, int minLength, char padChar)
Returns a string, of length at least minLength, consisting of string prepended with as many copies of padChar as are necessary to reach that length. For example,
padStart("7", 3, '0') returns "007"
padStart("2010", 3, '0') returns "2010"
See Formatter for a richer set of formatting capabilities.
string - the string which should appear at the end of the resultminLength - the minimum length the resulting string must have. Can be zero or negative, in which case the input string is always returned.padChar - the character to insert at the beginning of the result until the minimum length is reachedpublic static String padEnd(String string, int minLength, char padChar)
Returns a string, of length at least minLength, consisting of string appended with as many copies of padChar as are necessary to reach that length. For example,
padEnd("4.", 5, '0') returns "4.000"
padEnd("2010", 3, '!') returns "2010"
See Formatter for a richer set of formatting capabilities.
string - the string which should appear at the beginning of the resultminLength - the minimum length the resulting string must have. Can be zero or negative, in which case the input string is always returned.padChar - the character to append to the end of the result until the minimum length is reachedpublic static String repeat(String string, int count)
Returns a string consisting of a specific number of concatenated copies of an input string. For example, repeat("hey", 3) returns the string "heyheyhey".
string - any non-null stringcount - the number of times to repeat it; a nonnegative integerstring repeated count times (the empty string if count is zero)IllegalArgumentException - if count is negativepublic static String commonPrefix(CharSequence a, CharSequence b)
Returns the longest string prefix such that a.toString().startsWith(prefix) && b.toString().startsWith(prefix), taking care not to split surrogate pairs. If a and b have no common prefix, returns the empty string.
public static String commonSuffix(CharSequence a, CharSequence b)
Returns the longest string suffix such that a.toString().endsWith(suffix) && b.toString().endsWith(suffix), taking care not to split surrogate pairs. If a and b have no common suffix, returns the empty string.