J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2003-2004 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.util.regex; |
| 27 | |
| 28 | /** |
| 29 | * The result of a match operation. |
| 30 | * |
| 31 | * <p>This interface contains query methods used to determine the |
| 32 | * results of a match against a regular expression. The match boundaries, |
| 33 | * groups and group boundaries can be seen but not modified through |
| 34 | * a <code>MatchResult</code>. |
| 35 | * |
| 36 | * @author Michael McCloskey |
| 37 | * @see Matcher |
| 38 | * @since 1.5 |
| 39 | */ |
| 40 | public interface MatchResult { |
| 41 | |
| 42 | /** |
| 43 | * Returns the start index of the match. |
| 44 | * |
| 45 | * @return The index of the first character matched |
| 46 | * |
| 47 | * @throws IllegalStateException |
| 48 | * If no match has yet been attempted, |
| 49 | * or if the previous match operation failed |
| 50 | */ |
| 51 | public int start(); |
| 52 | |
| 53 | /** |
| 54 | * Returns the start index of the subsequence captured by the given group |
| 55 | * during this match. |
| 56 | * |
| 57 | * <p> <a href="Pattern.html#cg">Capturing groups</a> are indexed from left |
| 58 | * to right, starting at one. Group zero denotes the entire pattern, so |
| 59 | * the expression <i>m.</i><tt>start(0)</tt> is equivalent to |
| 60 | * <i>m.</i><tt>start()</tt>. </p> |
| 61 | * |
| 62 | * @param group |
| 63 | * The index of a capturing group in this matcher's pattern |
| 64 | * |
| 65 | * @return The index of the first character captured by the group, |
| 66 | * or <tt>-1</tt> if the match was successful but the group |
| 67 | * itself did not match anything |
| 68 | * |
| 69 | * @throws IllegalStateException |
| 70 | * If no match has yet been attempted, |
| 71 | * or if the previous match operation failed |
| 72 | * |
| 73 | * @throws IndexOutOfBoundsException |
| 74 | * If there is no capturing group in the pattern |
| 75 | * with the given index |
| 76 | */ |
| 77 | public int start(int group); |
| 78 | |
| 79 | /** |
| 80 | * Returns the offset after the last character matched. </p> |
| 81 | * |
| 82 | * @return @return The offset after the last character matched |
| 83 | * |
| 84 | * @throws IllegalStateException |
| 85 | * If no match has yet been attempted, |
| 86 | * or if the previous match operation failed |
| 87 | */ |
| 88 | public int end(); |
| 89 | |
| 90 | /** |
| 91 | * Returns the offset after the last character of the subsequence |
| 92 | * captured by the given group during this match. |
| 93 | * |
| 94 | * <p> <a href="Pattern.html#cg">Capturing groups</a> are indexed from left |
| 95 | * to right, starting at one. Group zero denotes the entire pattern, so |
| 96 | * the expression <i>m.</i><tt>end(0)</tt> is equivalent to |
| 97 | * <i>m.</i><tt>end()</tt>. </p> |
| 98 | * |
| 99 | * @param group |
| 100 | * The index of a capturing group in this matcher's pattern |
| 101 | * |
| 102 | * @return The offset after the last character captured by the group, |
| 103 | * or <tt>-1</tt> if the match was successful |
| 104 | * but the group itself did not match anything |
| 105 | * |
| 106 | * @throws IllegalStateException |
| 107 | * If no match has yet been attempted, |
| 108 | * or if the previous match operation failed |
| 109 | * |
| 110 | * @throws IndexOutOfBoundsException |
| 111 | * If there is no capturing group in the pattern |
| 112 | * with the given index |
| 113 | */ |
| 114 | public int end(int group); |
| 115 | |
| 116 | /** |
| 117 | * Returns the input subsequence matched by the previous match. |
| 118 | * |
| 119 | * <p> For a matcher <i>m</i> with input sequence <i>s</i>, |
| 120 | * the expressions <i>m.</i><tt>group()</tt> and |
| 121 | * <i>s.</i><tt>substring(</tt><i>m.</i><tt>start(),</tt> <i>m.</i><tt>end())</tt> |
| 122 | * are equivalent. </p> |
| 123 | * |
| 124 | * <p> Note that some patterns, for example <tt>a*</tt>, match the empty |
| 125 | * string. This method will return the empty string when the pattern |
| 126 | * successfully matches the empty string in the input. </p> |
| 127 | * |
| 128 | * @return The (possibly empty) subsequence matched by the previous match, |
| 129 | * in string form |
| 130 | * |
| 131 | * @throws IllegalStateException |
| 132 | * If no match has yet been attempted, |
| 133 | * or if the previous match operation failed |
| 134 | */ |
| 135 | public String group(); |
| 136 | |
| 137 | /** |
| 138 | * Returns the input subsequence captured by the given group during the |
| 139 | * previous match operation. |
| 140 | * |
| 141 | * <p> For a matcher <i>m</i>, input sequence <i>s</i>, and group index |
| 142 | * <i>g</i>, the expressions <i>m.</i><tt>group(</tt><i>g</i><tt>)</tt> and |
| 143 | * <i>s.</i><tt>substring(</tt><i>m.</i><tt>start(</tt><i>g</i><tt>),</tt> <i>m.</i><tt>end(</tt><i>g</i><tt>))</tt> |
| 144 | * are equivalent. </p> |
| 145 | * |
| 146 | * <p> <a href="Pattern.html#cg">Capturing groups</a> are indexed from left |
| 147 | * to right, starting at one. Group zero denotes the entire pattern, so |
| 148 | * the expression <tt>m.group(0)</tt> is equivalent to <tt>m.group()</tt>. |
| 149 | * </p> |
| 150 | * |
| 151 | * <p> If the match was successful but the group specified failed to match |
| 152 | * any part of the input sequence, then <tt>null</tt> is returned. Note |
| 153 | * that some groups, for example <tt>(a*)</tt>, match the empty string. |
| 154 | * This method will return the empty string when such a group successfully |
| 155 | * matches the empty string in the input. </p> |
| 156 | * |
| 157 | * @param group |
| 158 | * The index of a capturing group in this matcher's pattern |
| 159 | * |
| 160 | * @return The (possibly empty) subsequence captured by the group |
| 161 | * during the previous match, or <tt>null</tt> if the group |
| 162 | * failed to match part of the input |
| 163 | * |
| 164 | * @throws IllegalStateException |
| 165 | * If no match has yet been attempted, |
| 166 | * or if the previous match operation failed |
| 167 | * |
| 168 | * @throws IndexOutOfBoundsException |
| 169 | * If there is no capturing group in the pattern |
| 170 | * with the given index |
| 171 | */ |
| 172 | public String group(int group); |
| 173 | |
| 174 | /** |
| 175 | * Returns the number of capturing groups in this match result's pattern. |
| 176 | * |
| 177 | * <p> Group zero denotes the entire pattern by convention. It is not |
| 178 | * included in this count. |
| 179 | * |
| 180 | * <p> Any non-negative integer smaller than or equal to the value |
| 181 | * returned by this method is guaranteed to be a valid group index for |
| 182 | * this matcher. </p> |
| 183 | * |
| 184 | * @return The number of capturing groups in this matcher's pattern |
| 185 | */ |
| 186 | public int groupCount(); |
| 187 | |
| 188 | } |