/*
* Copyright (c) 2000, 2003, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.lang;
/**
* 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 {@link * java.lang.Object#equals(java.lang.Object) equals} and {@link * java.lang.Object#hashCode() 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 * @since 1.4 * @spec JSR-51 */ public interface CharSequence { /** * Returns the length of this character sequence. The length is the number * of 16-bitchar
s in the sequence.
*
* @return the number of char
s in this sequence
*/
int length();
/**
* 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.
*
* @param index the 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()
*/
char charAt(int index);
/**
* 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 char
s) of the
* returned sequence is end - start, so if start == end
* then an empty sequence is returned.