Guava: Google Core Libraries for Java 32.1.2-jre · com.google.common.base.Strings

Access	Constructor and Description
private	Strings()

Method Summary

Modifier and Type	Method and Description
public 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.
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.
public static String	Returns: `string` itself if it is nonempty; `null` if it is empty or null emptyToNull(String the string to test and possibly return string) Returns the given string if it is nonempty; `null` otherwise.
public static boolean	Returns: `true` if the string is null or is the empty string isNullOrEmpty(String a string reference to check string) Returns `true` if the given string is null or is the empty string.
public static String	lenientFormat(String a string containing zero or more `"%s"` placeholder sequences. `null` is treated as the four-character string `"null"`. template, @Nullable Object... the arguments to be substituted into the message template. The first argument specified is substituted for the first occurrence of `"%s"` in the template, and so forth. A `null` argument is converted to the four-character string `"null"`; non-null values are converted to strings using `Object#toString()`. args) Returns the given `template` string with each occurrence of `"%s"` replaced with the corresponding argument value from `args`; or, if the placeholder and argument counts do not match, returns a best-effort form of that string.
private static String	lenientToString(Object o)
public static String	Returns: `string` itself if it is non-null; `""` if it is null nullToEmpty(String the string to test and possibly return string) Returns the given string if it is non-null; the empty string otherwise.
public static String	Returns: the padded string padEnd(String the string which should appear at the beginning of the result string, int the minimum length the resulting string must have. Can be zero or negative, in which case the input string is always returned. minLength, char the character to append to the end of the result until the minimum length is reached 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.
public static String	Returns: the padded string padStart(String the string which should appear at the end of the result string, int the minimum length the resulting string must have. Can be zero or negative, in which case the input string is always returned. minLength, char the character to insert at the beginning of the result until the minimum length is reached 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.
public static String	Returns: a string containing `string` repeated `count` times (the empty string if `count` is zero) repeat(String any non-null string string, int the number of times to repeat it; a nonnegative integer count) Returns a string consisting of a specific number of concatenated copies of an input string.
pack-priv static boolean	validSurrogatePairAt(CharSequence string, int index) True when a valid surrogate pair starts at the given `index` in the given `string`.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Strings	back to summary
private Strings()

Method Detail

commonPrefix back to summary

commonPrefix	back to summary
public 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. Since 11.0

public 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.

Since: 11.0

commonSuffix back to summary

commonSuffix	back to summary
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. Since 11.0

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.

Since: 11.0

emptyToNull back to summary

emptyToNull	back to summary
public static String emptyToNull(String string) Returns the given string if it is nonempty; `null` otherwise. Parameters string:String the string to test and possibly return Returns:String `string` itself if it is nonempty; `null` if it is empty or null Annotations @CheckForNull

public static String emptyToNull(String string)

Returns the given string if it is nonempty; null otherwise.

Parameters

string:String: the string to test and possibly return

Returns:String

string itself if it is nonempty; null if it is empty or null

Annotations

@CheckForNull

isNullOrEmpty back to summary

isNullOrEmpty	back to summary
public static boolean isNullOrEmpty(String string) Returns `true` if the given string is null or is the empty string. Consider normalizing your string references with `nullToEmpty`. 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` either. Or, if you'd like to normalize "in the other direction," converting empty strings to `null`, you can use `emptyToNull`. Parameters string:String a string reference to check Returns:boolean `true` if the string is null or is the empty string

public static boolean isNullOrEmpty(String string)

Returns true if the given string is null or is the empty string.

Consider normalizing your string references with nullToEmpty. 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 either. Or, if you'd like to normalize "in the other direction," converting empty strings to null, you can use emptyToNull.

Parameters

string:String: a string reference to check

Returns:boolean

true if the string is null or is the empty string

lenientFormat back to summary

lenientFormat	back to summary
public static String lenientFormat(String template, @Nullable Object... args) Returns the given `template` string with each occurrence of `"%s"` replaced with the corresponding argument value from `args`; or, if the placeholder and argument counts do not match, returns a best-effort form of that string. Will not throw an exception under normal conditions. Note For most string-formatting needs, use `String.format`, `PrintWriter.format`, and related methods. These support the full range of format specifiers, and alert you to usage errors by throwing `java.util.IllegalFormatException`. In certain cases, such as outputting debugging information or constructing a message to be used for another unchecked exception, an exception during string formatting would serve little purpose except to supplant the real information you were trying to provide. These are the cases this method is made for; it instead generates a best-effort string with all supplied argument values present. This method is also useful in environments such as GWT where `String.format` is not available. As an example, method implementations of the `Preconditions` class use this formatter, for both of the reasons just discussed. Warning Only the exact two-character placeholder sequence `"%s"` is recognized. Parameters template:String a string containing zero or more `"%s"` placeholder sequences. `null` is treated as the four-character string `"null"`. args:@Nullable Object[] the arguments to be substituted into the message template. The first argument specified is substituted for the first occurrence of `"%s"` in the template, and so forth. A `null` argument is converted to the four-character string `"null"`; non-null values are converted to strings using `Object#toString()`. Since 25.1

public static String lenientFormat(String template, @Nullable Object... args)

Returns the given template string with each occurrence of "%s" replaced with the corresponding argument value from args; or, if the placeholder and argument counts do not match, returns a best-effort form of that string. Will not throw an exception under normal conditions.

Note

For most string-formatting needs, use String.format, PrintWriter.format, and related methods. These support the full range of format specifiers, and alert you to usage errors by throwing java.util.IllegalFormatException.

In certain cases, such as outputting debugging information or constructing a message to be used for another unchecked exception, an exception during string formatting would serve little purpose except to supplant the real information you were trying to provide. These are the cases this method is made for; it instead generates a best-effort string with all supplied argument values present. This method is also useful in environments such as GWT where String.format is not available. As an example, method implementations of the Preconditions class use this formatter, for both of the reasons just discussed.

Warning

Only the exact two-character placeholder sequence "%s" is recognized.

Parameters

template:String: a string containing zero or more "%s" placeholder sequences. null is treated as the four-character string "null".
args:@Nullable Object[]: the arguments to be substituted into the message template. The first argument specified is substituted for the first occurrence of "%s" in the template, and so forth. A null argument is converted to the four-character string "null"; non-null values are converted to strings using Object#toString().

Since

25.1

lenientToString	back to summary
private static String lenientToString(Object o)

nullToEmpty back to summary

nullToEmpty	back to summary
public static String nullToEmpty(String string) Returns the given string if it is non-null; the empty string otherwise. Parameters string:String the string to test and possibly return Returns:String `string` itself if it is non-null; `""` if it is null

public static String nullToEmpty(String string)

Returns the given string if it is non-null; the empty string otherwise.

Parameters

string:String: the string to test and possibly return

Returns:String

string itself if it is non-null; "" if it is null

padEnd back to summary

padEnd	back to summary
public 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 `java.util.Formatter` for a richer set of formatting capabilities. Parameters string:String the string which should appear at the beginning of the result minLength:int the minimum length the resulting string must have. Can be zero or negative, in which case the input string is always returned. padChar:char the character to append to the end of the result until the minimum length is reached Returns:String the padded string

public 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 java.util.Formatter for a richer set of formatting capabilities.

Parameters

string:String: the string which should appear at the beginning of the result
minLength:int: the minimum length the resulting string must have. Can be zero or negative, in which case the input string is always returned.
padChar:char: the character to append to the end of the result until the minimum length is reached

Returns:String

the padded string

padStart back to summary

padStart	back to summary
public 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 `java.util.Formatter` for a richer set of formatting capabilities. Parameters string:String the string which should appear at the end of the result minLength:int the minimum length the resulting string must have. Can be zero or negative, in which case the input string is always returned. padChar:char the character to insert at the beginning of the result until the minimum length is reached Returns:String the padded string

public 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 java.util.Formatter for a richer set of formatting capabilities.

Parameters

string:String: the string which should appear at the end of the result
minLength:int: the minimum length the resulting string must have. Can be zero or negative, in which case the input string is always returned.
padChar:char: the character to insert at the beginning of the result until the minimum length is reached

Returns:String

the padded string

repeat back to summary

repeat	back to summary
public 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"`. Java 11+ users: use `string.repeat(count)` instead. Parameters string:String any non-null string count:int the number of times to repeat it; a nonnegative integer Returns:String a string containing `string` repeated `count` times (the empty string if `count` is zero) Annotations @InlineMe replacement:string.repeat(count) @InlineMeValidationDisabled:Java 11+ API only Exceptions IllegalArgumentException: if `count` is negative

public 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".

Java 11+ users: use string.repeat(count) instead.

Parameters

string:String: any non-null string
count:int: the number of times to repeat it; a nonnegative integer

Returns:String

a string containing string repeated count times (the empty string if count is zero)

Annotations

@InlineMe
replacement:string.repeat(count)
@InlineMeValidationDisabled:Java 11+ API only

Exceptions

IllegalArgumentException:: if count is negative

validSurrogatePairAt back to summary

validSurrogatePairAt	back to summary
pack-priv static boolean validSurrogatePairAt(CharSequence string, int index) True when a valid surrogate pair starts at the given `index` in the given `string`. Out-of-range indexes return false. Annotations @VisibleForTesting

pack-priv static boolean validSurrogatePairAt(CharSequence string, int index)

True when a valid surrogate pair starts at the given index in the given string. Out-of-range indexes return false.

Annotations

@VisibleForTesting

public final Class Strings

Constructor Summary

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Constructor Detail

Method Detail