java.lang

Interface CharSequence

All Known Implementing Classes:

String, StringBuffer, StringBuilder

public interface CharSequence

General functions on a sequence of chars. This interface is implemented by String, StringBuffer and CharBuffer to give a uniform way to get chars at a certain index, the number of characters in the sequence and a subrange of the chars. Indexes start at 0 and the last index is length()-1.

Even when classes implement this interface they are not always exchangeble because they might implement their compare, equals or hash function differently. This means that in general one should not use a CharSequence as keys in collections since two sequences with the same chars at the same indexes with the same length might not have the same hash code, be equal or be comparable since the are represented by different classes.

Since:

1.4

Author:

Mark Wielaard (mark@klomp.org)

Method Summary

Modifier and Type	Method and Description
char	charAt(int i) Returns the character at the given index.
int	length() Returns the length of the sequence.
CharSequence	subSequence(int begin, int end) Returns a new CharSequence of the indicated range.
String	toString() Returns the complete CharSequence as a String.

Method Detail

charAt

char charAt(int i)

Returns the character at the given index.

Parameters:

i - the index to retrieve from

Returns:

the character at that location

Throws:

IndexOutOfBoundsException - if i < 0 || i >= length() - 1

length

int length()

Returns the length of the sequence. This is the number of 16-bit characters in the sequence, which may differ from the length of the underlying encoding.

Returns:

the sequence length

subSequence

CharSequence subSequence(int begin,
                         int end)

Returns a new CharSequence of the indicated range.

Parameters:

begin - the start index (inclusive)

end - the end index (exclusive)

Returns:

a subsequence of this

Throws:

IndexOutOfBoundsException - if begin > end || begin < 0 || end > length()

toString

String toString()

Returns the complete CharSequence as a String. Classes that implement this interface should return a String which contains only the characters in the sequence in the correct order.

Overrides:

toString in class Object

Returns:

the character sequence as a String