A CharSequence is a readable sequence of char values. This interface provides uniform, read-only access to many different kinds of char sequences. A char value represents a character in the Basic Multilingual Plane (BMP) or a surrogate. Refer to Unicode Character Representation for details.

This interface does not refine the general contracts of the equals and hashCode methods. The result of comparing two objects that implement CharSequence is therefore, in general, undefined. Each object may be implemented by a different class, and there is no guarantee that each class will be capable of testing its instances for equality with those of the other. It is therefore inappropriate to use arbitrary CharSequence instances as elements in a set or as keys in a map.

@author
Mike McCloskey
@version
1.8 03/12/19
@since
1.4
@spec
JSR-51
Returns the char value at the specified index. An index ranges from zero to length() - 1. The first char value of the sequence is at index zero, the next at index one, and so on, as for array indexing.

If the char value specified by the index is a surrogate, the surrogate value is returned.

Parameters
indexthe index of the char value to be returned
Return
the specified char value
Throws
IndexOutOfBoundsException if the index argument is negative or not less than length()
Returns the length of this character sequence. The length is the number of 16-bit chars in the sequence.

Return
the number of chars in this sequence
Returns a new CharSequence that is a subsequence of this sequence. The subsequence starts with the char value at the specified index and ends with the char value at index end - 1. The length (in chars) of the returned sequence is end - start, so if start == end then an empty sequence is returned.

Parameters
startthe start index, inclusive
endthe end index, exclusive
Return
the specified subsequence
Throws
IndexOutOfBoundsException if start or end are negative, if end is greater than length(), or if start is greater than end
Returns a string containing the characters in this sequence in the same order as this sequence. The length of the string will be the length of this sequence.

Return
a string consisting of exactly this sequence of characters