| /* |
| * Copyright (C) 2007 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package java.util.regex; |
| |
| import java.io.IOException; |
| import java.io.ObjectInputStream; |
| import java.io.Serializable; |
| |
| /** |
| * Patterns are compiled regular expressions. In many cases, convenience methods such as |
| * {@link String#matches String.matches}, {@link String#replaceAll String.replaceAll} and |
| * {@link String#split String.split} will be preferable, but if you need to do a lot of work |
| * with the same regular expression, it may be more efficient to compile it once and reuse it. |
| * The {@code Pattern} class and its companion, {@link Matcher}, also offer more functionality |
| * than the small amount exposed by {@code String}. |
| * |
| * <pre> |
| * // String convenience methods: |
| * boolean sawFailures = s.matches("Failures: \\d+"); |
| * String farewell = s.replaceAll("Hello, (\\S+)", "Goodbye, $1"); |
| * String[] fields = s.split(":"); |
| * |
| * // Direct use of Pattern: |
| * Pattern p = Pattern.compile("Hello, (\\S+)"); |
| * Matcher m = p.matcher(inputString); |
| * while (m.find()) { // Find each match in turn; String can't do this. |
| * String name = m.group(1); // Access a submatch group; String can't do this. |
| * } |
| * </pre> |
| * |
| * <h3>Regular expression syntax</h3> |
| * <span class="datatable"> |
| * <style type="text/css"> |
| * .datatable td { padding-right: 20px; } |
| * </style> |
| * |
| * <p>Java supports a subset of Perl 5 regular expression syntax. An important gotcha is that Java |
| * has no regular expression literals, and uses plain old string literals instead. This means that |
| * you need an extra level of escaping. For example, the regular expression {@code \s+} has to |
| * be represented as the string {@code "\\s+"}. |
| * |
| * <h3>Escape sequences</h3> |
| * <p><table> |
| * <tr> <td> \ </td> <td>Quote the following metacharacter (so {@code \.} matches a literal {@code .}).</td> </tr> |
| * <tr> <td> \Q </td> <td>Quote all following metacharacters until {@code \E}.</td> </tr> |
| * <tr> <td> \E </td> <td>Stop quoting metacharacters (started by {@code \Q}).</td> </tr> |
| * <tr> <td> \\ </td> <td>A literal backslash.</td> </tr> |
| * <tr> <td> \u<i>hhhh</i> </td> <td>The Unicode character U+hhhh (in hex).</td> </tr> |
| * <tr> <td> \x<i>hh</i> </td> <td>The Unicode character U+00hh (in hex).</td> </tr> |
| * <tr> <td> \c<i>x</i> </td> <td>The ASCII control character ^x (so {@code \cH} would be ^H, U+0008).</td> </tr> |
| * |
| * <tr> <td> \a </td> <td>The ASCII bell character (U+0007).</td> </tr> |
| * <tr> <td> \e </td> <td>The ASCII ESC character (U+001b).</td> </tr> |
| * <tr> <td> \f </td> <td>The ASCII form feed character (U+000c).</td> </tr> |
| * <tr> <td> \n </td> <td>The ASCII newline character (U+000a).</td> </tr> |
| * <tr> <td> \r </td> <td>The ASCII carriage return character (U+000d).</td> </tr> |
| * <tr> <td> \t </td> <td>The ASCII tab character (U+0009).</td> </tr> |
| * </table> |
| * |
| * <h3>Character classes</h3> |
| * <p>It's possible to construct arbitrary character classes using set operations: |
| * <table> |
| * <tr> <td> [abc] </td> <td>Any one of {@code a}, {@code b}, or {@code c}. (Enumeration.)</td> </tr> |
| * <tr> <td> [a-c] </td> <td>Any one of {@code a}, {@code b}, or {@code c}. (Range.)</td> </tr> |
| * <tr> <td> [^abc] </td> <td>Any character <i>except</i> {@code a}, {@code b}, or {@code c}. (Negation.)</td> </tr> |
| * <tr> <td> [[a-f][0-9]] </td> <td>Any character in either range. (Union.)</td> </tr> |
| * <tr> <td> [[a-z]&&[jkl]] </td> <td>Any character in both ranges. (Intersection.)</td> </tr> |
| * </table> |
| * <p>Most of the time, the built-in character classes are more useful: |
| * <table> |
| * <tr> <td> \d </td> <td>Any digit character.</td> </tr> |
| * <tr> <td> \D </td> <td>Any non-digit character.</td> </tr> |
| * <tr> <td> \s </td> <td>Any whitespace character.</td> </tr> |
| * <tr> <td> \S </td> <td>Any non-whitespace character.</td> </tr> |
| * <tr> <td> \w </td> <td>Any word character.</td> </tr> |
| * <tr> <td> \W </td> <td>Any non-word character.</td> </tr> |
| * <tr> <td> \p{<i>NAME</i>} </td> <td> Any character in the class with the given <i>NAME</i>. </td> </tr> |
| * <tr> <td> \P{<i>NAME</i>} </td> <td> Any character <i>not</i> in the named class. </td> </tr> |
| * </table> |
| * <p>There are a variety of named classes: |
| * <ul> |
| * <li><a href="../../lang/Character.html#unicode_categories">Unicode category names</a>, |
| * prefixed by {@code Is}. For example {@code \p{IsLu}} for all uppercase letters. |
| * <li>POSIX class names. These are 'Alnum', 'Alpha', 'ASCII', 'Blank', 'Cntrl', 'Digit', |
| * 'Graph', 'Lower', 'Print', 'Punct', 'Upper', 'XDigit'. |
| * <li>Unicode block names, as used by {@link java.lang.Character.UnicodeBlock#forName} prefixed |
| * by {@code In}. For example {@code \p{InHebrew}} for all characters in the Hebrew block. |
| * <li>Character method names. These are all non-deprecated methods from {@link java.lang.Character} |
| * whose name starts with {@code is}, but with the {@code is} replaced by {@code java}. |
| * For example, {@code \p{javaLowerCase}}. |
| * </ul> |
| * |
| * <h3>Quantifiers</h3> |
| * <p>Quantifiers match some number of instances of the preceding regular expression. |
| * <table> |
| * <tr> <td> * </td> <td>Zero or more.</td> </tr> |
| * <tr> <td> ? </td> <td>Zero or one.</td> </tr> |
| * <tr> <td> + </td> <td>One or more.</td> </tr> |
| * <tr> <td> {<i>n</i>} </td> <td>Exactly <i>n</i>.</td> </tr> |
| * <tr> <td> {<i>n,</i>} </td> <td>At least <i>n</i>.</td> </tr> |
| * <tr> <td> {<i>n</i>,<i>m</i>} </td> <td>At least <i>n</i> but not more than <i>m</i>.</td> </tr> |
| * </table> |
| * <p>Quantifiers are "greedy" by default, meaning that they will match the longest possible input |
| * sequence. There are also non-greedy quantifiers that match the shortest possible input sequence. |
| * They're same as the greedy ones but with a trailing {@code ?}: |
| * <table> |
| * <tr> <td> *? </td> <td>Zero or more (non-greedy).</td> </tr> |
| * <tr> <td> ?? </td> <td>Zero or one (non-greedy).</td> </tr> |
| * <tr> <td> +? </td> <td>One or more (non-greedy).</td> </tr> |
| * <tr> <td> {<i>n</i>}? </td> <td>Exactly <i>n</i> (non-greedy).</td> </tr> |
| * <tr> <td> {<i>n,</i>}? </td> <td>At least <i>n</i> (non-greedy).</td> </tr> |
| * <tr> <td> {<i>n</i>,<i>m</i>}? </td> <td>At least <i>n</i> but not more than <i>m</i> (non-greedy).</td> </tr> |
| * </table> |
| * <p>Quantifiers allow backtracking by default. There are also possessive quantifiers to prevent |
| * backtracking. They're same as the greedy ones but with a trailing {@code +}: |
| * <table> |
| * <tr> <td> *+ </td> <td>Zero or more (possessive).</td> </tr> |
| * <tr> <td> ?+ </td> <td>Zero or one (possessive).</td> </tr> |
| * <tr> <td> ++ </td> <td>One or more (possessive).</td> </tr> |
| * <tr> <td> {<i>n</i>}+ </td> <td>Exactly <i>n</i> (possessive).</td> </tr> |
| * <tr> <td> {<i>n,</i>}+ </td> <td>At least <i>n</i> (possessive).</td> </tr> |
| * <tr> <td> {<i>n</i>,<i>m</i>}+ </td> <td>At least <i>n</i> but not more than <i>m</i> (possessive).</td> </tr> |
| * </table> |
| * |
| * <h3>Zero-width assertions</h3> |
| * <p><table> |
| * <tr> <td> ^ </td> <td>At beginning of line.</td> </tr> |
| * <tr> <td> $ </td> <td>At end of line.</td> </tr> |
| * <tr> <td> \A </td> <td>At beginning of input.</td> </tr> |
| * <tr> <td> \b </td> <td>At word boundary.</td> </tr> |
| * <tr> <td> \B </td> <td>At non-word boundary.</td> </tr> |
| * <tr> <td> \G </td> <td>At end of previous match.</td> </tr> |
| * <tr> <td> \z </td> <td>At end of input.</td> </tr> |
| * <tr> <td> \Z </td> <td>At end of input, or before newline at end.</td> </tr> |
| * </table> |
| * |
| * <h3>Look-around assertions</h3> |
| * <p>Look-around assertions assert that the subpattern does (positive) or doesn't (negative) match |
| * after (look-ahead) or before (look-behind) the current position, without including the matched |
| * text in the containing match. The maximum length of possible matches for look-behind patterns |
| * must not be unbounded. |
| * <p><table> |
| * <tr> <td> (?=<i>a</i>) </td> <td>Zero-width positive look-ahead.</td> </tr> |
| * <tr> <td> (?!<i>a</i>) </td> <td>Zero-width negative look-ahead.</td> </tr> |
| * <tr> <td> (?<=<i>a</i>) </td> <td>Zero-width positive look-behind.</td> </tr> |
| * <tr> <td> (?<!<i>a</i>) </td> <td>Zero-width negative look-behind.</td> </tr> |
| * </table> |
| * |
| * <h3>Groups</h3> |
| * |
| * <p><table> |
| * <tr> <td> (<i>a</i>) </td> <td>A capturing group.</td> </tr> |
| * <tr> <td> (?:<i>a</i>) </td> <td>A non-capturing group.</td> </tr> |
| * <tr> <td> (?><i>a</i>) </td> <td>An independent non-capturing group. (The first match of the subgroup is the only match tried.)</td> </tr> |
| * <tr> <td> \<i>n</i> </td> <td>The text already matched by capturing group <i>n</i>.</td> </tr> |
| * </table> |
| * <p>See {@link Matcher#group} for details of how capturing groups are numbered and accessed. |
| * |
| * <h3>Operators</h3> |
| * <p><table> |
| * <tr> <td> <i>ab</i> </td> <td>Expression <i>a</i> followed by expression <i>b</i>.</td> </tr> |
| * <tr> <td> <i>a</i>|<i>b</i> </td> <td>Either expression <i>a</i> or expression <i>b</i>.</td> </tr> |
| * </table> |
| * |
| * <a name="flags"><h3>Flags</h3></a> |
| * <p><table> |
| * <tr> <td> (?dimsux-dimsux:<i>a</i>) </td> <td>Evaluates the expression <i>a</i> with the given flags enabled/disabled.</td> </tr> |
| * <tr> <td> (?dimsux-dimsux) </td> <td>Evaluates the rest of the pattern with the given flags enabled/disabled.</td> </tr> |
| * </table> |
| * |
| * <p>The flags are: |
| * <table> |
| * <tr><td>{@code i}</td> <td>{@link #CASE_INSENSITIVE}</td> <td>case insensitive matching</td></tr> |
| * <tr><td>{@code d}</td> <td>{@link #UNIX_LINES}</td> <td>only accept {@code '\n'} as a line terminator</td></tr> |
| * <tr><td>{@code m}</td> <td>{@link #MULTILINE}</td> <td>allow {@code ^} and {@code $} to match beginning/end of any line</td></tr> |
| * <tr><td>{@code s}</td> <td>{@link #DOTALL}</td> <td>allow {@code .} to match {@code '\n'} ("s" for "single line")</td></tr> |
| * <tr><td>{@code u}</td> <td>{@link #UNICODE_CASE}</td> <td>enable Unicode case folding</td></tr> |
| * <tr><td>{@code x}</td> <td>{@link #COMMENTS}</td> <td>allow whitespace and comments</td></tr> |
| * </table> |
| * <p>Either set of flags may be empty. For example, {@code (?i-m)} would turn on case-insensitivity |
| * and turn off multiline mode, {@code (?i)} would just turn on case-insensitivity, |
| * and {@code (?-m)} would just turn off multiline mode. |
| * <p>Note that on Android, {@code UNICODE_CASE} is always on: case-insensitive matching will |
| * always be Unicode-aware. |
| * <p>There are two other flags not settable via this mechanism: {@link #CANON_EQ} and |
| * {@link #LITERAL}. Attempts to use {@link #CANON_EQ} on Android will throw an exception. |
| * </span> |
| * |
| * <h3>Implementation notes</h3> |
| * |
| * <p>The regular expression implementation used in Android is provided by |
| * <a href="http://www.icu-project.org">ICU</a>. The notation for the regular |
| * expressions is mostly a superset of those used in other Java language |
| * implementations. This means that existing applications will normally work as |
| * expected, but in rare cases Android may accept a regular expression that is |
| * not accepted by other implementations. |
| * |
| * <p>In some cases, Android will recognize that a regular expression is a simple |
| * special case that can be handled more efficiently. This is true of both the convenience methods |
| * in {@code String} and the methods in {@code Pattern}. |
| * |
| * @see Matcher |
| */ |
| public final class Pattern implements Serializable { |
| |
| private static final long serialVersionUID = 5073258162644648461L; |
| |
| /** |
| * This constant specifies that a pattern matches Unix line endings ('\n') |
| * only against the '.', '^', and '$' meta characters. Corresponds to {@code (?d)}. |
| */ |
| public static final int UNIX_LINES = 0x01; |
| |
| /** |
| * This constant specifies that a {@code Pattern} is matched |
| * case-insensitively. That is, the patterns "a+" and "A+" would both match |
| * the string "aAaAaA". See {@link #UNICODE_CASE}. Corresponds to {@code (?i)}. |
| */ |
| public static final int CASE_INSENSITIVE = 0x02; |
| |
| /** |
| * This constant specifies that a {@code Pattern} may contain whitespace or |
| * comments. Otherwise comments and whitespace are taken as literal |
| * characters. Corresponds to {@code (?x)}. |
| */ |
| public static final int COMMENTS = 0x04; |
| |
| /** |
| * This constant specifies that the meta characters '^' and '$' match only |
| * the beginning and end of an input line, respectively. Normally, they |
| * match the beginning and the end of the complete input. Corresponds to {@code (?m)}. |
| */ |
| public static final int MULTILINE = 0x08; |
| |
| /** |
| * This constant specifies that the whole {@code Pattern} is to be taken |
| * literally, that is, all meta characters lose their meanings. |
| */ |
| public static final int LITERAL = 0x10; |
| |
| /** |
| * This constant specifies that the '.' meta character matches arbitrary |
| * characters, including line endings, which is normally not the case. |
| * Corresponds to {@code (?s)}. |
| */ |
| public static final int DOTALL = 0x20; |
| |
| /** |
| * This constant specifies that a {@code Pattern} that uses case-insensitive matching |
| * will use Unicode case folding. On Android, {@code UNICODE_CASE} is always on: |
| * case-insensitive matching will always be Unicode-aware. If your code is intended to |
| * be portable and uses case-insensitive matching on non-ASCII characters, you should |
| * use this flag. Corresponds to {@code (?u)}. |
| */ |
| public static final int UNICODE_CASE = 0x40; |
| |
| /** |
| * This constant specifies that a character in a {@code Pattern} and a |
| * character in the input string only match if they are canonically |
| * equivalent. It is (currently) not supported in Android. |
| */ |
| public static final int CANON_EQ = 0x80; |
| |
| private final String pattern; |
| private final int flags; |
| |
| transient int address; |
| |
| /** |
| * Returns a {@link Matcher} for this pattern applied to the given {@code input}. |
| * The {@code Matcher} can be used to match the {@code Pattern} against the |
| * whole input, find occurrences of the {@code Pattern} in the input, or |
| * replace parts of the input. |
| */ |
| public Matcher matcher(CharSequence input) { |
| return new Matcher(this, input); |
| } |
| |
| /** |
| * Splits the given {@code input} at occurrences of this pattern. |
| * |
| * <p>If this pattern does not occur in the input, the result is an |
| * array containing the input (converted from a {@code CharSequence} to |
| * a {@code String}). |
| * |
| * <p>Otherwise, the {@code limit} parameter controls the contents of the |
| * returned array as described below. |
| * |
| * @param limit |
| * Determines the maximum number of entries in the resulting |
| * array, and the treatment of trailing empty strings. |
| * <ul> |
| * <li>For n > 0, the resulting array contains at most n |
| * entries. If this is fewer than the number of matches, the |
| * final entry will contain all remaining input. |
| * <li>For n < 0, the length of the resulting array is |
| * exactly the number of occurrences of the {@code Pattern} |
| * plus one for the text after the final separator. |
| * All entries are included. |
| * <li>For n == 0, the result is as for n < 0, except |
| * trailing empty strings will not be returned. (Note that |
| * the case where the input is itself an empty string is |
| * special, as described above, and the limit parameter does |
| * not apply there.) |
| * </ul> |
| */ |
| public String[] split(CharSequence input, int limit) { |
| return Splitter.split(this, pattern, input.toString(), limit); |
| } |
| |
| /** |
| * Equivalent to {@code split(input, 0)}. |
| */ |
| public String[] split(CharSequence input) { |
| return split(input, 0); |
| } |
| |
| /** |
| * Returns the regular expression supplied to {@code compile}. |
| */ |
| public String pattern() { |
| return pattern; |
| } |
| |
| @Override |
| public String toString() { |
| return pattern; |
| } |
| |
| /** |
| * Returns the flags supplied to {@code compile}. |
| */ |
| public int flags() { |
| return flags; |
| } |
| |
| /** |
| * Returns a compiled form of the given {@code regularExpression}, as modified by the |
| * given {@code flags}. See the <a href="#flags">flags overview</a> for more on flags. |
| * |
| * @throws PatternSyntaxException if the regular expression is syntactically incorrect. |
| * |
| * @see #CANON_EQ |
| * @see #CASE_INSENSITIVE |
| * @see #COMMENTS |
| * @see #DOTALL |
| * @see #LITERAL |
| * @see #MULTILINE |
| * @see #UNICODE_CASE |
| * @see #UNIX_LINES |
| */ |
| public static Pattern compile(String regularExpression, int flags) throws PatternSyntaxException { |
| return new Pattern(regularExpression, flags); |
| } |
| |
| /** |
| * Equivalent to {@code Pattern.compile(pattern, 0)}. |
| */ |
| public static Pattern compile(String pattern) { |
| return new Pattern(pattern, 0); |
| } |
| |
| private Pattern(String pattern, int flags) throws PatternSyntaxException { |
| if ((flags & CANON_EQ) != 0) { |
| throw new UnsupportedOperationException("CANON_EQ flag not supported"); |
| } |
| this.pattern = pattern; |
| this.flags = flags; |
| compile(); |
| } |
| |
| private void compile() throws PatternSyntaxException { |
| if (pattern == null) { |
| throw new NullPointerException("pattern == null"); |
| } |
| |
| String icuPattern = pattern; |
| if ((flags & LITERAL) != 0) { |
| icuPattern = quote(pattern); |
| } |
| |
| // These are the flags natively supported by ICU. |
| // They even have the same value in native code. |
| int icuFlags = flags & (CASE_INSENSITIVE | COMMENTS | MULTILINE | DOTALL | UNIX_LINES); |
| |
| address = compileImpl(icuPattern, icuFlags); |
| } |
| |
| /** |
| * Tests whether the given {@code regularExpression} matches the given {@code input}. |
| * Equivalent to {@code Pattern.compile(regularExpression).matcher(input).matches()}. |
| * If the same regular expression is to be used for multiple operations, it may be more |
| * efficient to reuse a compiled {@code Pattern}. |
| * |
| * @see Pattern#compile(java.lang.String, int) |
| * @see Matcher#matches() |
| */ |
| public static boolean matches(String regularExpression, CharSequence input) { |
| return new Matcher(new Pattern(regularExpression, 0), input).matches(); |
| } |
| |
| /** |
| * Quotes the given {@code string} using "\Q" and "\E", so that all |
| * meta-characters lose their special meaning. This method correctly |
| * escapes embedded instances of "\Q" or "\E". If the entire result |
| * is to be passed verbatim to {@link #compile}, it's usually clearer |
| * to use the {@link #LITERAL} flag instead. |
| */ |
| public static String quote(String string) { |
| StringBuilder sb = new StringBuilder(); |
| sb.append("\\Q"); |
| int apos = 0; |
| int k; |
| while ((k = string.indexOf("\\E", apos)) >= 0) { |
| sb.append(string.substring(apos, k + 2)).append("\\\\E\\Q"); |
| apos = k + 2; |
| } |
| return sb.append(string.substring(apos)).append("\\E").toString(); |
| } |
| |
| @Override protected void finalize() throws Throwable { |
| try { |
| closeImpl(address); |
| } finally { |
| super.finalize(); |
| } |
| } |
| |
| private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException { |
| s.defaultReadObject(); |
| compile(); |
| } |
| |
| private static native void closeImpl(int addr); |
| private static native int compileImpl(String regex, int flags); |
| } |