/* * Copyright (c) 1999, 2012, 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.util.regex; import java.util.Objects; /** * An engine that performs match operations on a {@link java.lang.CharSequence * character sequence} by interpreting a {@link Pattern}. * *

A matcher is created from a pattern by invoking the pattern's {@link * Pattern#matcher matcher} method. Once created, a matcher can be used to * perform three different kinds of match operations: * *

* *

Each of these methods returns a boolean indicating success or failure. * More information about a successful match can be obtained by querying the * state of the matcher. * *

A matcher finds matches in a subset of its input called the * region. By default, the region contains all of the matcher's input. * The region can be modified via the{@link #region region} method and queried * via the {@link #regionStart regionStart} and {@link #regionEnd regionEnd} * methods. The way that the region boundaries interact with some pattern * constructs can be changed. See {@link #useAnchoringBounds * useAnchoringBounds} and {@link #useTransparentBounds useTransparentBounds} * for more details. * *

This class also defines methods for replacing matched subsequences with * new strings whose contents can, if desired, be computed from the match * result. The {@link #appendReplacement appendReplacement} and {@link * #appendTail appendTail} methods can be used in tandem in order to collect * the result into an existing string buffer, or the more convenient {@link * #replaceAll replaceAll} method can be used to create a string in which every * matching subsequence in the input sequence is replaced. * *

The explicit state of a matcher includes the start and end indices of * the most recent successful match. It also includes the start and end * indices of the input subsequence captured by each capturing group in the pattern as well as a total * count of such subsequences. As a convenience, methods are also provided for * returning these captured subsequences in string form. * *

The explicit state of a matcher is initially undefined; attempting to * query any part of it before a successful match will cause an {@link * IllegalStateException} to be thrown. The explicit state of a matcher is * recomputed by every match operation. * *

The implicit state of a matcher includes the input character sequence as * well as the append position, which is initially zero and is updated * by the {@link #appendReplacement appendReplacement} method. * *

A matcher may be reset explicitly by invoking its {@link #reset()} * method or, if a new input sequence is desired, its {@link * #reset(java.lang.CharSequence) reset(CharSequence)} method. Resetting a * matcher discards its explicit state information and sets the append position * to zero. * *

Instances of this class are not safe for use by multiple concurrent * threads.

* * * @author Mike McCloskey * @author Mark Reinhold * @author JSR-51 Expert Group * @since 1.4 * @spec JSR-51 */ public final class Matcher implements MatchResult { /** * The Pattern object that created this Matcher. */ Pattern parentPattern; /** * The storage used by groups. They may contain invalid values if * a group was skipped during the matching. */ int[] groups; /** * The range within the sequence that is to be matched. Anchors * will match at these "hard" boundaries. Changing the region * changes these values. */ int from, to; /** * Lookbehind uses this value to ensure that the subexpression * match ends at the point where the lookbehind was encountered. */ int lookbehindTo; /** * The original string being matched. */ CharSequence text; /** * Matcher state used by the last node. NOANCHOR is used when a * match does not have to consume all of the input. ENDANCHOR is * the mode used for matching all the input. */ static final int ENDANCHOR = 1; static final int NOANCHOR = 0; int acceptMode = NOANCHOR; /** * The range of string that last matched the pattern. If the last * match failed then first is -1; last initially holds 0 then it * holds the index of the end of the last match (which is where the * next search starts). */ int first = -1, last = 0; /** * The end index of what matched in the last match operation. */ int oldLast = -1; /** * The index of the last position appended in a substitution. */ int lastAppendPosition = 0; /** * Storage used by nodes to tell what repetition they are on in * a pattern, and where groups begin. The nodes themselves are stateless, * so they rely on this field to hold state during a match. */ int[] locals; /** * Boolean indicating whether or not more input could change * the results of the last match. * * If hitEnd is true, and a match was found, then more input * might cause a different match to be found. * If hitEnd is true and a match was not found, then more * input could cause a match to be found. * If hitEnd is false and a match was found, then more input * will not change the match. * If hitEnd is false and a match was not found, then more * input will not cause a match to be found. */ boolean hitEnd; /** * Boolean indicating whether or not more input could change * a positive match into a negative one. * * If requireEnd is true, and a match was found, then more * input could cause the match to be lost. * If requireEnd is false and a match was found, then more * input might change the match but the match won't be lost. * If a match was not found, then requireEnd has no meaning. */ boolean requireEnd; /** * If transparentBounds is true then the boundaries of this * matcher's region are transparent to lookahead, lookbehind, * and boundary matching constructs that try to see beyond them. */ boolean transparentBounds = false; /** * If anchoringBounds is true then the boundaries of this * matcher's region match anchors such as ^ and $. */ boolean anchoringBounds = true; /** * No default constructor. */ Matcher() { } /** * All matchers have the state used by Pattern during a match. */ Matcher(Pattern parent, CharSequence text) { this.parentPattern = parent; this.text = text; // Allocate state storage int parentGroupCount = Math.max(parent.capturingGroupCount, 10); groups = new int[parentGroupCount * 2]; locals = new int[parent.localCount]; // Put fields into initial states reset(); } /** * Returns the pattern that is interpreted by this matcher. * * @return The pattern for which this matcher was created */ public Pattern pattern() { return parentPattern; } /** * Returns the match state of this matcher as a {@link MatchResult}. * The result is unaffected by subsequent operations performed upon this * matcher. * * @return a MatchResult with the state of this matcher * @since 1.5 */ public MatchResult toMatchResult() { Matcher result = new Matcher(this.parentPattern, text.toString()); result.first = this.first; result.last = this.last; result.groups = this.groups.clone(); return result; } /** * Changes the Pattern that this Matcher uses to * find matches with. * *

This method causes this matcher to lose information * about the groups of the last match that occurred. The * matcher's position in the input is maintained and its * last append position is unaffected.

* * @param newPattern * The new pattern used by this matcher * @return This matcher * @throws IllegalArgumentException * If newPattern is null * @since 1.5 */ public Matcher usePattern(Pattern newPattern) { if (newPattern == null) throw new IllegalArgumentException("Pattern cannot be null"); parentPattern = newPattern; // Reallocate state storage int parentGroupCount = Math.max(newPattern.capturingGroupCount, 10); groups = new int[parentGroupCount * 2]; locals = new int[newPattern.localCount]; for (int i = 0; i < groups.length; i++) groups[i] = -1; for (int i = 0; i < locals.length; i++) locals[i] = -1; return this; } /** * Resets this matcher. * *

Resetting a matcher discards all of its explicit state information * and sets its append position to zero. The matcher's region is set to the * default region, which is its entire character sequence. The anchoring * and transparency of this matcher's region boundaries are unaffected. * * @return This matcher */ public Matcher reset() { first = -1; last = 0; oldLast = -1; for(int i=0; i Resetting a matcher discards all of its explicit state information * and sets its append position to zero. The matcher's region is set to * the default region, which is its entire character sequence. The * anchoring and transparency of this matcher's region boundaries are * unaffected. * * @param input * The new input character sequence * * @return This matcher */ public Matcher reset(CharSequence input) { text = input; return reset(); } /** * Returns the start index of the previous match.

* * @return The index of the first character matched * * @throws IllegalStateException * If no match has yet been attempted, * or if the previous match operation failed */ public int start() { if (first < 0) throw new IllegalStateException("No match available"); return first; } /** * Returns the start index of the subsequence captured by the given group * during the previous match operation. * *

Capturing groups are indexed from left * to right, starting at one. Group zero denotes the entire pattern, so * the expression m.start(0) is equivalent to * m.start().

* * @param group * The index of a capturing group in this matcher's pattern * * @return The index of the first character captured by the group, * or -1 if the match was successful but the group * itself did not match anything * * @throws IllegalStateException * If no match has yet been attempted, * or if the previous match operation failed * * @throws IndexOutOfBoundsException * If there is no capturing group in the pattern * with the given index */ public int start(int group) { if (first < 0) throw new IllegalStateException("No match available"); if (group < 0 || group > groupCount()) throw new IndexOutOfBoundsException("No group " + group); return groups[group * 2]; } /** * Returns the start index of the subsequence captured by the given * named-capturing group during the * previous match operation. * * @param name * The name of a named-capturing group in this matcher's pattern * * @return The index of the first character captured by the group, * or {@code -1} if the match was successful but the group * itself did not match anything * * @throws IllegalStateException * If no match has yet been attempted, * or if the previous match operation failed * * @throws IllegalArgumentException * If there is no capturing group in the pattern * with the given name * @since 1.8 */ public int start(String name) { return groups[getMatchedGroupIndex(name) * 2]; } /** * Returns the offset after the last character matched.

* * @return The offset after the last character matched * * @throws IllegalStateException * If no match has yet been attempted, * or if the previous match operation failed */ public int end() { if (first < 0) throw new IllegalStateException("No match available"); return last; } /** * Returns the offset after the last character of the subsequence * captured by the given group during the previous match operation. * *

Capturing groups are indexed from left * to right, starting at one. Group zero denotes the entire pattern, so * the expression m.end(0) is equivalent to * m.end().

* * @param group * The index of a capturing group in this matcher's pattern * * @return The offset after the last character captured by the group, * or -1 if the match was successful * but the group itself did not match anything * * @throws IllegalStateException * If no match has yet been attempted, * or if the previous match operation failed * * @throws IndexOutOfBoundsException * If there is no capturing group in the pattern * with the given index */ public int end(int group) { if (first < 0) throw new IllegalStateException("No match available"); if (group < 0 || group > groupCount()) throw new IndexOutOfBoundsException("No group " + group); return groups[group * 2 + 1]; } /** * Returns the offset after the last character of the subsequence * captured by the given named-capturing * group during the previous match operation. * * @param name * The name of a named-capturing group in this matcher's pattern * * @return The offset after the last character captured by the group, * or {@code -1} if the match was successful * but the group itself did not match anything * * @throws IllegalStateException * If no match has yet been attempted, * or if the previous match operation failed * * @throws IllegalArgumentException * If there is no capturing group in the pattern * with the given name */ public int end(String name) { return groups[getMatchedGroupIndex(name) * 2 + 1]; } /** * Returns the input subsequence matched by the previous match. * *

For a matcher m with input sequence s, * the expressions m.group() and * s.substring(m.start(), m.end()) * are equivalent.

* *

Note that some patterns, for example a*, match the empty * string. This method will return the empty string when the pattern * successfully matches the empty string in the input.

* * @return The (possibly empty) subsequence matched by the previous match, * in string form * * @throws IllegalStateException * If no match has yet been attempted, * or if the previous match operation failed */ public String group() { return group(0); } /** * Returns the input subsequence captured by the given group during the * previous match operation. * *

For a matcher m, input sequence s, and group index * g, the expressions m.group(g) and * s.substring(m.start(g), m.end(g)) * are equivalent.

* *

Capturing groups are indexed from left * to right, starting at one. Group zero denotes the entire pattern, so * the expression m.group(0) is equivalent to m.group(). *

* *

If the match was successful but the group specified failed to match * any part of the input sequence, then null is returned. Note * that some groups, for example (a*), match the empty string. * This method will return the empty string when such a group successfully * matches the empty string in the input.

* * @param group * The index of a capturing group in this matcher's pattern * * @return The (possibly empty) subsequence captured by the group * during the previous match, or null if the group * failed to match part of the input * * @throws IllegalStateException * If no match has yet been attempted, * or if the previous match operation failed * * @throws IndexOutOfBoundsException * If there is no capturing group in the pattern * with the given index */ public String group(int group) { if (first < 0) throw new IllegalStateException("No match found"); if (group < 0 || group > groupCount()) throw new IndexOutOfBoundsException("No group " + group); if ((groups[group*2] == -1) || (groups[group*2+1] == -1)) return null; return getSubSequence(groups[group * 2], groups[group * 2 + 1]).toString(); } /** * Returns the input subsequence captured by the given * named-capturing group during the previous * match operation. * *

If the match was successful but the group specified failed to match * any part of the input sequence, then null is returned. Note * that some groups, for example (a*), match the empty string. * This method will return the empty string when such a group successfully * matches the empty string in the input.

* * @param name * The name of a named-capturing group in this matcher's pattern * * @return The (possibly empty) subsequence captured by the named group * during the previous match, or null if the group * failed to match part of the input * * @throws IllegalStateException * If no match has yet been attempted, * or if the previous match operation failed * * @throws IllegalArgumentException * If there is no capturing group in the pattern * with the given name * @since 1.7 */ public String group(String name) { int group = getMatchedGroupIndex(name); if ((groups[group*2] == -1) || (groups[group*2+1] == -1)) return null; return getSubSequence(groups[group * 2], groups[group * 2 + 1]).toString(); } /** * Returns the number of capturing groups in this matcher's pattern. * *

Group zero denotes the entire pattern by convention. It is not * included in this count. * *

Any non-negative integer smaller than or equal to the value * returned by this method is guaranteed to be a valid group index for * this matcher.

* * @return The number of capturing groups in this matcher's pattern */ public int groupCount() { return parentPattern.capturingGroupCount - 1; } /** * Attempts to match the entire region against the pattern. * *

If the match succeeds then more information can be obtained via the * start, end, and group methods.

* * @return true if, and only if, the entire region sequence * matches this matcher's pattern */ public boolean matches() { return match(from, ENDANCHOR); } /** * Attempts to find the next subsequence of the input sequence that matches * the pattern. * *

This method starts at the beginning of this matcher's region, or, if * a previous invocation of the method was successful and the matcher has * not since been reset, at the first character not matched by the previous * match. * *

If the match succeeds then more information can be obtained via the * start, end, and group methods.

* * @return true if, and only if, a subsequence of the input * sequence matches this matcher's pattern */ public boolean find() { int nextSearchIndex = last; if (nextSearchIndex == first) nextSearchIndex++; // If next search starts before region, start it at region if (nextSearchIndex < from) nextSearchIndex = from; // If next search starts beyond region then it fails if (nextSearchIndex > to) { for (int i = 0; i < groups.length; i++) groups[i] = -1; return false; } return search(nextSearchIndex); } /** * Resets this matcher and then attempts to find the next subsequence of * the input sequence that matches the pattern, starting at the specified * index. * *

If the match succeeds then more information can be obtained via the * start, end, and group methods, and subsequent * invocations of the {@link #find()} method will start at the first * character not matched by this match.

* * @throws IndexOutOfBoundsException * If start is less than zero or if start is greater than the * length of the input sequence. * * @return true if, and only if, a subsequence of the input * sequence starting at the given index matches this matcher's * pattern */ public boolean find(int start) { int limit = getTextLength(); if ((start < 0) || (start > limit)) throw new IndexOutOfBoundsException("Illegal start index"); reset(); return search(start); } /** * Attempts to match the input sequence, starting at the beginning of the * region, against the pattern. * *

Like the {@link #matches matches} method, this method always starts * at the beginning of the region; unlike that method, it does not * require that the entire region be matched. * *

If the match succeeds then more information can be obtained via the * start, end, and group methods.

* * @return true if, and only if, a prefix of the input * sequence matches this matcher's pattern */ public boolean lookingAt() { return match(from, NOANCHOR); } /** * Returns a literal replacement String for the specified * String. * * This method produces a String that will work * as a literal replacement s in the * appendReplacement method of the {@link Matcher} class. * The String produced will match the sequence of characters * in s treated as a literal sequence. Slashes ('\') and * dollar signs ('$') will be given no special meaning. * * @param s The string to be literalized * @return A literal string replacement * @since 1.5 */ public static String quoteReplacement(String s) { if ((s.indexOf('\\') == -1) && (s.indexOf('$') == -1)) return s; StringBuilder sb = new StringBuilder(); for (int i=0; i This method performs the following actions:

* *
    * *

  1. It reads characters from the input sequence, starting at the * append position, and appends them to the given string buffer. It * stops after reading the last character preceding the previous match, * that is, the character at index {@link * #start()} - 1.

    2. * *

  2. It appends the given replacement string to the string buffer. *

    3. * *

  3. It sets the append position of this matcher to the index of * the last character matched, plus one, that is, to {@link #end()}. *

    4. * *
* *

The replacement string may contain references to subsequences * captured during the previous match: Each occurrence of * ${name} or $g * will be replaced by the result of evaluating the corresponding * {@link #group(String) group(name)} or {@link #group(int) group(g)} * respectively. For $g, * the first number after the $ is always treated as part of * the group reference. Subsequent numbers are incorporated into g if * they would form a legal group reference. Only the numerals '0' * through '9' are considered as potential components of the group * reference. If the second group matched the string "foo", for * example, then passing the replacement string "$2bar" would * cause "foobar" to be appended to the string buffer. A dollar * sign ($) may be included as a literal in the replacement * string by preceding it with a backslash (\$). * *

Note that backslashes (\) and dollar signs ($) in * the replacement string may cause the results to be different than if it * were being treated as a literal replacement string. Dollar signs may be * treated as references to captured subsequences as described above, and * backslashes are used to escape literal characters in the replacement * string. * *

This method is intended to be used in a loop together with the * {@link #appendTail appendTail} and {@link #find find} methods. The * following code, for example, writes one dog two dogs in the * yard to the standard-output stream:

* * 
     * Pattern p = Pattern.compile("cat");
     * Matcher m = p.matcher("one cat two cats in the yard");
     * StringBuffer sb = new StringBuffer();
     * while (m.find()) {
     *     m.appendReplacement(sb, "dog");
     * }
     * m.appendTail(sb);
     * System.out.println(sb.toString());
* * @param sb * The target string buffer * * @param replacement * The replacement string * * @return This matcher * * @throws IllegalStateException * If no match has yet been attempted, * or if the previous match operation failed * * @throws IllegalArgumentException * If the replacement string refers to a named-capturing * group that does not exist in the pattern * * @throws IndexOutOfBoundsException * If the replacement string refers to a capturing group * that does not exist in the pattern */ public Matcher appendReplacement(StringBuffer sb, String replacement) { // If no match, return error if (first < 0) throw new IllegalStateException("No match available"); // Process substitution string to replace group references with groups int cursor = 0; StringBuilder result = new StringBuilder(); while (cursor < replacement.length()) { char nextChar = replacement.charAt(cursor); if (nextChar == '\\') { cursor++; if (cursor == replacement.length()) throw new IllegalArgumentException( "character to be escaped is missing"); nextChar = replacement.charAt(cursor); result.append(nextChar); cursor++; } else if (nextChar == '$') { // Skip past $ cursor++; // Throw IAE if this "$" is the last character in replacement if (cursor == replacement.length()) throw new IllegalArgumentException( "Illegal group reference: group index is missing"); nextChar = replacement.charAt(cursor); int refNum = -1; if (nextChar == '{') { cursor++; StringBuilder gsb = new StringBuilder(); while (cursor < replacement.length()) { nextChar = replacement.charAt(cursor); if (ASCII.isLower(nextChar) || ASCII.isUpper(nextChar) || ASCII.isDigit(nextChar)) { gsb.append(nextChar); cursor++; } else { break; } } if (gsb.length() == 0) throw new IllegalArgumentException( "named capturing group has 0 length name"); if (nextChar != '}') throw new IllegalArgumentException( "named capturing group is missing trailing '}'"); String gname = gsb.toString(); if (ASCII.isDigit(gname.charAt(0))) throw new IllegalArgumentException( "capturing group name {" + gname + "} starts with digit character"); if (!parentPattern.namedGroups().containsKey(gname)) throw new IllegalArgumentException( "No group with name {" + gname + "}"); refNum = parentPattern.namedGroups().get(gname); cursor++; } else { // The first number is always a group refNum = (int)nextChar - '0'; if ((refNum < 0)||(refNum > 9)) throw new IllegalArgumentException( "Illegal group reference"); cursor++; // Capture the largest legal group string boolean done = false; while (!done) { if (cursor >= replacement.length()) { break; } int nextDigit = replacement.charAt(cursor) - '0'; if ((nextDigit < 0)||(nextDigit > 9)) { // not a number break; } int newRefNum = (refNum * 10) + nextDigit; if (groupCount() < newRefNum) { done = true; } else { refNum = newRefNum; cursor++; } } } // Append group if (start(refNum) != -1 && end(refNum) != -1) result.append(text, start(refNum), end(refNum)); } else { result.append(nextChar); cursor++; } } // Append the intervening text sb.append(text, lastAppendPosition, first); // Append the match substitution sb.append(result); lastAppendPosition = last; return this; } /** * Implements a terminal append-and-replace step. * *

This method reads characters from the input sequence, starting at * the append position, and appends them to the given string buffer. It is * intended to be invoked after one or more invocations of the {@link * #appendReplacement appendReplacement} method in order to copy the * remainder of the input sequence.

* * @param sb * The target string buffer * * @return The target string buffer */ public StringBuffer appendTail(StringBuffer sb) { sb.append(text, lastAppendPosition, getTextLength()); return sb; } /** * Replaces every subsequence of the input sequence that matches the * pattern with the given replacement string. * *

This method first resets this matcher. It then scans the input * sequence looking for matches of the pattern. Characters that are not * part of any match are appended directly to the result string; each match * is replaced in the result by the replacement string. The replacement * string may contain references to captured subsequences as in the {@link * #appendReplacement appendReplacement} method. * *

Note that backslashes (\) and dollar signs ($) in * the replacement string may cause the results to be different than if it * were being treated as a literal replacement string. Dollar signs may be * treated as references to captured subsequences as described above, and * backslashes are used to escape literal characters in the replacement * string. * *

Given the regular expression a*b, the input * "aabfooaabfooabfoob", and the replacement string * "-", an invocation of this method on a matcher for that * expression would yield the string "-foo-foo-foo-". * *

Invoking this method changes this matcher's state. If the matcher * is to be used in further matching operations then it should first be * reset.

* * @param replacement * The replacement string * * @return The string constructed by replacing each matching subsequence * by the replacement string, substituting captured subsequences * as needed */ public String replaceAll(String replacement) { reset(); boolean result = find(); if (result) { StringBuffer sb = new StringBuffer(); do { appendReplacement(sb, replacement); result = find(); } while (result); appendTail(sb); return sb.toString(); } return text.toString(); } /** * Replaces the first subsequence of the input sequence that matches the * pattern with the given replacement string. * *

This method first resets this matcher. It then scans the input * sequence looking for a match of the pattern. Characters that are not * part of the match are appended directly to the result string; the match * is replaced in the result by the replacement string. The replacement * string may contain references to captured subsequences as in the {@link * #appendReplacement appendReplacement} method. * *

Note that backslashes (\) and dollar signs ($) in * the replacement string may cause the results to be different than if it * were being treated as a literal replacement string. Dollar signs may be * treated as references to captured subsequences as described above, and * backslashes are used to escape literal characters in the replacement * string. * *

Given the regular expression dog, the input * "zzzdogzzzdogzzz", and the replacement string * "cat", an invocation of this method on a matcher for that * expression would yield the string "zzzcatzzzdogzzz".

* *

Invoking this method changes this matcher's state. If the matcher * is to be used in further matching operations then it should first be * reset.

* * @param replacement * The replacement string * @return The string constructed by replacing the first matching * subsequence by the replacement string, substituting captured * subsequences as needed */ public String replaceFirst(String replacement) { if (replacement == null) throw new NullPointerException("replacement"); reset(); if (!find()) return text.toString(); StringBuffer sb = new StringBuffer(); appendReplacement(sb, replacement); appendTail(sb); return sb.toString(); } /** * Sets the limits of this matcher's region. The region is the part of the * input sequence that will be searched to find a match. Invoking this * method resets the matcher, and then sets the region to start at the * index specified by the start parameter and end at the * index specified by the end parameter. * *

Depending on the transparency and anchoring being used (see * {@link #useTransparentBounds useTransparentBounds} and * {@link #useAnchoringBounds useAnchoringBounds}), certain constructs such * as anchors may behave differently at or around the boundaries of the * region. * * @param start * The index to start searching at (inclusive) * @param end * The index to end searching at (exclusive) * @throws IndexOutOfBoundsException * If start or end is less than zero, if * start is greater than the length of the input sequence, if * end is greater than the length of the input sequence, or if * start is greater than end. * @return this matcher * @since 1.5 */ public Matcher region(int start, int end) { if ((start < 0) || (start > getTextLength())) throw new IndexOutOfBoundsException("start"); if ((end < 0) || (end > getTextLength())) throw new IndexOutOfBoundsException("end"); if (start > end) throw new IndexOutOfBoundsException("start > end"); reset(); from = start; to = end; return this; } /** * Reports the start index of this matcher's region. The * searches this matcher conducts are limited to finding matches * within {@link #regionStart regionStart} (inclusive) and * {@link #regionEnd regionEnd} (exclusive). * * @return The starting point of this matcher's region * @since 1.5 */ public int regionStart() { return from; } /** * Reports the end index (exclusive) of this matcher's region. * The searches this matcher conducts are limited to finding matches * within {@link #regionStart regionStart} (inclusive) and * {@link #regionEnd regionEnd} (exclusive). * * @return the ending point of this matcher's region * @since 1.5 */ public int regionEnd() { return to; } /** * Queries the transparency of region bounds for this matcher. * *

This method returns true if this matcher uses * transparent bounds, false if it uses opaque * bounds. * *

See {@link #useTransparentBounds useTransparentBounds} for a * description of transparent and opaque bounds. * *

By default, a matcher uses opaque region boundaries. * * @return true iff this matcher is using transparent bounds, * false otherwise. * @see java.util.regex.Matcher#useTransparentBounds(boolean) * @since 1.5 */ public boolean hasTransparentBounds() { return transparentBounds; } /** * Sets the transparency of region bounds for this matcher. * *

Invoking this method with an argument of true will set this * matcher to use transparent bounds. If the boolean * argument is false, then opaque bounds will be used. * *

Using transparent bounds, the boundaries of this * matcher's region are transparent to lookahead, lookbehind, * and boundary matching constructs. Those constructs can see beyond the * boundaries of the region to see if a match is appropriate. * *

Using opaque bounds, the boundaries of this matcher's * region are opaque to lookahead, lookbehind, and boundary matching * constructs that may try to see beyond them. Those constructs cannot * look past the boundaries so they will fail to match anything outside * of the region. * *

By default, a matcher uses opaque bounds. * * @param b a boolean indicating whether to use opaque or transparent * regions * @return this matcher * @see java.util.regex.Matcher#hasTransparentBounds * @since 1.5 */ public Matcher useTransparentBounds(boolean b) { transparentBounds = b; return this; } /** * Queries the anchoring of region bounds for this matcher. * *

This method returns true if this matcher uses * anchoring bounds, false otherwise. * *

See {@link #useAnchoringBounds useAnchoringBounds} for a * description of anchoring bounds. * *

By default, a matcher uses anchoring region boundaries. * * @return true iff this matcher is using anchoring bounds, * false otherwise. * @see java.util.regex.Matcher#useAnchoringBounds(boolean) * @since 1.5 */ public boolean hasAnchoringBounds() { return anchoringBounds; } /** * Sets the anchoring of region bounds for this matcher. * *

Invoking this method with an argument of true will set this * matcher to use anchoring bounds. If the boolean * argument is false, then non-anchoring bounds will be * used. * *

Using anchoring bounds, the boundaries of this * matcher's region match anchors such as ^ and $. * *

Without anchoring bounds, the boundaries of this * matcher's region will not match anchors such as ^ and $. * *

By default, a matcher uses anchoring region boundaries. * * @param b a boolean indicating whether or not to use anchoring bounds. * @return this matcher * @see java.util.regex.Matcher#hasAnchoringBounds * @since 1.5 */ public Matcher useAnchoringBounds(boolean b) { anchoringBounds = b; return this; } /** *

Returns the string representation of this matcher. The * string representation of a Matcher contains information * that may be useful for debugging. The exact format is unspecified. * * @return The string representation of this matcher * @since 1.5 */ public String toString() { StringBuilder sb = new StringBuilder(); sb.append("java.util.regex.Matcher"); sb.append("[pattern=" + pattern()); sb.append(" region="); sb.append(regionStart() + "," + regionEnd()); sb.append(" lastmatch="); if ((first >= 0) && (group() != null)) { sb.append(group()); } sb.append("]"); return sb.toString(); } /** *

Returns true if the end of input was hit by the search engine in * the last match operation performed by this matcher. * *

When this method returns true, then it is possible that more input * would have changed the result of the last search. * * @return true iff the end of input was hit in the last match; false * otherwise * @since 1.5 */ public boolean hitEnd() { return hitEnd; } /** *

Returns true if more input could change a positive match into a * negative one. * *

If this method returns true, and a match was found, then more * input could cause the match to be lost. If this method returns false * and a match was found, then more input might change the match but the * match won't be lost. If a match was not found, then requireEnd has no * meaning. * * @return true iff more input could change a positive match into a * negative one. * @since 1.5 */ public boolean requireEnd() { return requireEnd; } /** * Initiates a search to find a Pattern within the given bounds. * The groups are filled with default values and the match of the root * of the state machine is called. The state machine will hold the state * of the match as it proceeds in this matcher. * * Matcher.from is not set here, because it is the "hard" boundary * of the start of the search which anchors will set to. The from param * is the "soft" boundary of the start of the search, meaning that the * regex tries to match at that index but ^ won't match there. Subsequent * calls to the search methods start at a new "soft" boundary which is * the end of the previous match. */ boolean search(int from) { this.hitEnd = false; this.requireEnd = false; from = from < 0 ? 0 : from; this.first = from; this.oldLast = oldLast < 0 ? from : oldLast; for (int i = 0; i < groups.length; i++) groups[i] = -1; acceptMode = NOANCHOR; boolean result = parentPattern.root.match(this, from, text); if (!result) this.first = -1; this.oldLast = this.last; return result; } /** * Initiates a search for an anchored match to a Pattern within the given * bounds. The groups are filled with default values and the match of the * root of the state machine is called. The state machine will hold the * state of the match as it proceeds in this matcher. */ boolean match(int from, int anchor) { this.hitEnd = false; this.requireEnd = false; from = from < 0 ? 0 : from; this.first = from; this.oldLast = oldLast < 0 ? from : oldLast; for (int i = 0; i < groups.length; i++) groups[i] = -1; acceptMode = anchor; boolean result = parentPattern.matchRoot.match(this, from, text); if (!result) this.first = -1; this.oldLast = this.last; return result; } /** * Returns the end index of the text. * * @return the index after the last character in the text */ int getTextLength() { return text.length(); } /** * Generates a String from this Matcher's input in the specified range. * * @param beginIndex the beginning index, inclusive * @param endIndex the ending index, exclusive * @return A String generated from this Matcher's input */ CharSequence getSubSequence(int beginIndex, int endIndex) { return text.subSequence(beginIndex, endIndex); } /** * Returns this Matcher's input character at index i. * * @return A char from the specified index */ char charAt(int i) { return text.charAt(i); } /** * Returns the group index of the matched capturing group. * * @return the index of the named-capturing group */ int getMatchedGroupIndex(String name) { Objects.requireNonNull(name, "Group name"); if (first < 0) throw new IllegalStateException("No match found"); if (!parentPattern.namedGroups().containsKey(name)) throw new IllegalArgumentException("No group with name <" + name + ">"); return parentPattern.namedGroups().get(name); } }