J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2000-2003 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package java.lang; |
| 27 | |
| 28 | |
| 29 | /** |
| 30 | * A <tt>CharSequence</tt> is a readable sequence of <code>char</code> values. This |
| 31 | * interface provides uniform, read-only access to many different kinds of |
| 32 | * <code>char</code> sequences. |
| 33 | * A <code>char</code> value represents a character in the <i>Basic |
| 34 | * Multilingual Plane (BMP)</i> or a surrogate. Refer to <a |
| 35 | * href="Character.html#unicode">Unicode Character Representation</a> for details. |
| 36 | * |
| 37 | * <p> This interface does not refine the general contracts of the {@link |
| 38 | * java.lang.Object#equals(java.lang.Object) equals} and {@link |
| 39 | * java.lang.Object#hashCode() hashCode} methods. The result of comparing two |
| 40 | * objects that implement <tt>CharSequence</tt> is therefore, in general, |
| 41 | * undefined. Each object may be implemented by a different class, and there |
| 42 | * is no guarantee that each class will be capable of testing its instances |
| 43 | * for equality with those of the other. It is therefore inappropriate to use |
| 44 | * arbitrary <tt>CharSequence</tt> instances as elements in a set or as keys in |
| 45 | * a map. </p> |
| 46 | * |
| 47 | * @author Mike McCloskey |
| 48 | * @since 1.4 |
| 49 | * @spec JSR-51 |
| 50 | */ |
| 51 | |
| 52 | public interface CharSequence { |
| 53 | |
| 54 | /** |
| 55 | * Returns the length of this character sequence. The length is the number |
| 56 | * of 16-bit <code>char</code>s in the sequence.</p> |
| 57 | * |
| 58 | * @return the number of <code>char</code>s in this sequence |
| 59 | */ |
| 60 | int length(); |
| 61 | |
| 62 | /** |
| 63 | * Returns the <code>char</code> value at the specified index. An index ranges from zero |
| 64 | * to <tt>length() - 1</tt>. The first <code>char</code> value of the sequence is at |
| 65 | * index zero, the next at index one, and so on, as for array |
| 66 | * indexing. </p> |
| 67 | * |
| 68 | * <p>If the <code>char</code> value specified by the index is a |
| 69 | * <a href="Character.html#unicode">surrogate</a>, the surrogate |
| 70 | * value is returned. |
| 71 | * |
| 72 | * @param index the index of the <code>char</code> value to be returned |
| 73 | * |
| 74 | * @return the specified <code>char</code> value |
| 75 | * |
| 76 | * @throws IndexOutOfBoundsException |
| 77 | * if the <tt>index</tt> argument is negative or not less than |
| 78 | * <tt>length()</tt> |
| 79 | */ |
| 80 | char charAt(int index); |
| 81 | |
| 82 | /** |
| 83 | * Returns a new <code>CharSequence</code> that is a subsequence of this sequence. |
| 84 | * The subsequence starts with the <code>char</code> value at the specified index and |
| 85 | * ends with the <code>char</code> value at index <tt>end - 1</tt>. The length |
| 86 | * (in <code>char</code>s) of the |
| 87 | * returned sequence is <tt>end - start</tt>, so if <tt>start == end</tt> |
| 88 | * then an empty sequence is returned. </p> |
| 89 | * |
| 90 | * @param start the start index, inclusive |
| 91 | * @param end the end index, exclusive |
| 92 | * |
| 93 | * @return the specified subsequence |
| 94 | * |
| 95 | * @throws IndexOutOfBoundsException |
| 96 | * if <tt>start</tt> or <tt>end</tt> are negative, |
| 97 | * if <tt>end</tt> is greater than <tt>length()</tt>, |
| 98 | * or if <tt>start</tt> is greater than <tt>end</tt> |
| 99 | */ |
| 100 | CharSequence subSequence(int start, int end); |
| 101 | |
| 102 | /** |
| 103 | * Returns a string containing the characters in this sequence in the same |
| 104 | * order as this sequence. The length of the string will be the length of |
| 105 | * this sequence. </p> |
| 106 | * |
| 107 | * @return a string consisting of exactly this sequence of characters |
| 108 | */ |
| 109 | public String toString(); |
| 110 | |
| 111 | } |