474 *
475 * @throws IllegalStateException
476 * If no match has yet been attempted,
477 * or if the previous match operation failed
478 *
479 * @throws IndexOutOfBoundsException
480 * If there is no capturing group in the pattern
481 * with the given index
482 */
483 public String group(int group) {
484 if (first < 0)
485 throw new IllegalStateException("No match found");
486 if (group < 0 || group > groupCount())
487 throw new IndexOutOfBoundsException("No group " + group);
488 if ((groups[group*2] == -1) || (groups[group*2+1] == -1))
489 return null;
490 return getSubSequence(groups[group * 2], groups[group * 2 + 1]).toString();
491 }
492
493 /**
494 * Returns the number of capturing groups in this matcher's pattern.
495 *
496 * <p> Group zero denotes the entire pattern by convention. It is not
497 * included in this count.
498 *
499 * <p> Any non-negative integer smaller than or equal to the value
500 * returned by this method is guaranteed to be a valid group index for
501 * this matcher. </p>
502 *
503 * @return The number of capturing groups in this matcher's pattern
504 */
505 public int groupCount() {
506 return parentPattern.capturingGroupCount - 1;
507 }
508
509 /**
510 * Attempts to match the entire region against the pattern.
511 *
512 * <p> If the match succeeds then more information can be obtained via the
513 * <tt>start</tt>, <tt>end</tt>, and <tt>group</tt> methods. </p>
632 *
633 * <ol>
634 *
635 * <li><p> It reads characters from the input sequence, starting at the
636 * append position, and appends them to the given string buffer. It
637 * stops after reading the last character preceding the previous match,
638 * that is, the character at index {@link
639 * #start()} <tt>-</tt> <tt>1</tt>. </p></li>
640 *
641 * <li><p> It appends the given replacement string to the string buffer.
642 * </p></li>
643 *
644 * <li><p> It sets the append position of this matcher to the index of
645 * the last character matched, plus one, that is, to {@link #end()}.
646 * </p></li>
647 *
648 * </ol>
649 *
650 * <p> The replacement string may contain references to subsequences
651 * captured during the previous match: Each occurrence of
652 * <tt>$</tt><i>g</i><tt></tt> will be replaced by the result of
653 * evaluating {@link #group(int) group}<tt>(</tt><i>g</i><tt>)</tt>.
654 * The first number after the <tt>$</tt> is always treated as part of
655 * the group reference. Subsequent numbers are incorporated into g if
656 * they would form a legal group reference. Only the numerals '0'
657 * through '9' are considered as potential components of the group
658 * reference. If the second group matched the string <tt>"foo"</tt>, for
659 * example, then passing the replacement string <tt>"$2bar"</tt> would
660 * cause <tt>"foobar"</tt> to be appended to the string buffer. A dollar
661 * sign (<tt>$</tt>) may be included as a literal in the replacement
662 * string by preceding it with a backslash (<tt>\$</tt>).
663 *
664 * <p> Note that backslashes (<tt>\</tt>) and dollar signs (<tt>$</tt>) in
665 * the replacement string may cause the results to be different than if it
666 * were being treated as a literal replacement string. Dollar signs may be
667 * treated as references to captured subsequences as described above, and
668 * backslashes are used to escape literal characters in the replacement
669 * string.
670 *
671 * <p> This method is intended to be used in a loop together with the
672 * {@link #appendTail appendTail} and {@link #find find} methods. The
673 * following code, for example, writes <tt>one dog two dogs in the
674 * yard</tt> to the standard-output stream: </p>
678 * Matcher m = p.matcher("one cat two cats in the yard");
679 * StringBuffer sb = new StringBuffer();
680 * while (m.find()) {
681 * m.appendReplacement(sb, "dog");
682 * }
683 * m.appendTail(sb);
684 * System.out.println(sb.toString());</pre></blockquote>
685 *
686 * @param sb
687 * The target string buffer
688 *
689 * @param replacement
690 * The replacement string
691 *
692 * @return This matcher
693 *
694 * @throws IllegalStateException
695 * If no match has yet been attempted,
696 * or if the previous match operation failed
697 *
698 * @throws IndexOutOfBoundsException
699 * If the replacement string refers to a capturing group
700 * that does not exist in the pattern
701 */
702 public Matcher appendReplacement(StringBuffer sb, String replacement) {
703
704 // If no match, return error
705 if (first < 0)
706 throw new IllegalStateException("No match available");
707
708 // Process substitution string to replace group references with groups
709 int cursor = 0;
710 StringBuilder result = new StringBuilder();
711
712 while (cursor < replacement.length()) {
713 char nextChar = replacement.charAt(cursor);
714 if (nextChar == '\\') {
715 cursor++;
716 nextChar = replacement.charAt(cursor);
717 result.append(nextChar);
718 cursor++;
719 } else if (nextChar == '$') {
720 // Skip past $
721 cursor++;
722 // The first number is always a group
723 int refNum = (int)replacement.charAt(cursor) - '0';
724 if ((refNum < 0)||(refNum > 9))
725 throw new IllegalArgumentException(
726 "Illegal group reference");
727 cursor++;
728
729 // Capture the largest legal group string
730 boolean done = false;
731 while (!done) {
732 if (cursor >= replacement.length()) {
733 break;
734 }
735 int nextDigit = replacement.charAt(cursor) - '0';
736 if ((nextDigit < 0)||(nextDigit > 9)) { // not a number
737 break;
738 }
739 int newRefNum = (refNum * 10) + nextDigit;
740 if (groupCount() < newRefNum) {
741 done = true;
742 } else {
743 refNum = newRefNum;
744 cursor++;
745 }
746 }
747 // Append group
748 if (start(refNum) != -1 && end(refNum) != -1)
749 result.append(text, start(refNum), end(refNum));
750 } else {
751 result.append(nextChar);
752 cursor++;
753 }
754 }
755 // Append the intervening text
756 sb.append(text, lastAppendPosition, first);
757 // Append the match substitution
758 sb.append(result);
759
760 lastAppendPosition = last;
761 return this;
762 }
763
764 /**
765 * Implements a terminal append-and-replace step.
766 *
|
474 *
475 * @throws IllegalStateException
476 * If no match has yet been attempted,
477 * or if the previous match operation failed
478 *
479 * @throws IndexOutOfBoundsException
480 * If there is no capturing group in the pattern
481 * with the given index
482 */
483 public String group(int group) {
484 if (first < 0)
485 throw new IllegalStateException("No match found");
486 if (group < 0 || group > groupCount())
487 throw new IndexOutOfBoundsException("No group " + group);
488 if ((groups[group*2] == -1) || (groups[group*2+1] == -1))
489 return null;
490 return getSubSequence(groups[group * 2], groups[group * 2 + 1]).toString();
491 }
492
493 /**
494 * Returns the input subsequence captured by the given
495 * <a href="Pattern.html#groupname">named-capturing group</a> during the previous
496 * match operation.
497 *
498 * <p> If the match was successful but the group specified failed to match
499 * any part of the input sequence, then <tt>null</tt> is returned. Note
500 * that some groups, for example <tt>(a*)</tt>, match the empty string.
501 * This method will return the empty string when such a group successfully
502 * matches the empty string in the input. </p>
503 *
504 * @param name
505 * The name of a named-capturing group in this matcher's pattern
506 *
507 * @return The (possibly empty) subsequence captured by the named group
508 * during the previous match, or <tt>null</tt> if the group
509 * failed to match part of the input
510 *
511 * @throws IllegalStateException
512 * If no match has yet been attempted,
513 * or if the previous match operation failed
514 *
515 * @throws IllegalArgumentException
516 * If there is no capturing group in the pattern
517 * with the given name
518 */
519 public String group(String name) {
520 if (name == null)
521 throw new NullPointerException("Null group name");
522 if (first < 0)
523 throw new IllegalStateException("No match found");
524 if (!parentPattern.namedGroups().containsKey(name))
525 throw new IllegalArgumentException("No group with name <" + name + ">");
526 int group = parentPattern.namedGroups().get(name);
527 if ((groups[group*2] == -1) || (groups[group*2+1] == -1))
528 return null;
529 return getSubSequence(groups[group * 2], groups[group * 2 + 1]).toString();
530 }
531
532 /**
533 * Returns the number of capturing groups in this matcher's pattern.
534 *
535 * <p> Group zero denotes the entire pattern by convention. It is not
536 * included in this count.
537 *
538 * <p> Any non-negative integer smaller than or equal to the value
539 * returned by this method is guaranteed to be a valid group index for
540 * this matcher. </p>
541 *
542 * @return The number of capturing groups in this matcher's pattern
543 */
544 public int groupCount() {
545 return parentPattern.capturingGroupCount - 1;
546 }
547
548 /**
549 * Attempts to match the entire region against the pattern.
550 *
551 * <p> If the match succeeds then more information can be obtained via the
552 * <tt>start</tt>, <tt>end</tt>, and <tt>group</tt> methods. </p>
671 *
672 * <ol>
673 *
674 * <li><p> It reads characters from the input sequence, starting at the
675 * append position, and appends them to the given string buffer. It
676 * stops after reading the last character preceding the previous match,
677 * that is, the character at index {@link
678 * #start()} <tt>-</tt> <tt>1</tt>. </p></li>
679 *
680 * <li><p> It appends the given replacement string to the string buffer.
681 * </p></li>
682 *
683 * <li><p> It sets the append position of this matcher to the index of
684 * the last character matched, plus one, that is, to {@link #end()}.
685 * </p></li>
686 *
687 * </ol>
688 *
689 * <p> The replacement string may contain references to subsequences
690 * captured during the previous match: Each occurrence of
691 * <tt>$</tt><<i>name</i>> or <tt>$</tt><i>g</i>
692 * will be replaced by the result of evaluating the corresponding
693 * {@link #group(String) group(name)} or {@link #group(int) group(g)</tt>}
694 * respectively. For <tt>$</tt><i>g</i><tt></tt>,
695 * the first number after the <tt>$</tt> is always treated as part of
696 * the group reference. Subsequent numbers are incorporated into g if
697 * they would form a legal group reference. Only the numerals '0'
698 * through '9' are considered as potential components of the group
699 * reference. If the second group matched the string <tt>"foo"</tt>, for
700 * example, then passing the replacement string <tt>"$2bar"</tt> would
701 * cause <tt>"foobar"</tt> to be appended to the string buffer. A dollar
702 * sign (<tt>$</tt>) may be included as a literal in the replacement
703 * string by preceding it with a backslash (<tt>\$</tt>).
704 *
705 * <p> Note that backslashes (<tt>\</tt>) and dollar signs (<tt>$</tt>) in
706 * the replacement string may cause the results to be different than if it
707 * were being treated as a literal replacement string. Dollar signs may be
708 * treated as references to captured subsequences as described above, and
709 * backslashes are used to escape literal characters in the replacement
710 * string.
711 *
712 * <p> This method is intended to be used in a loop together with the
713 * {@link #appendTail appendTail} and {@link #find find} methods. The
714 * following code, for example, writes <tt>one dog two dogs in the
715 * yard</tt> to the standard-output stream: </p>
719 * Matcher m = p.matcher("one cat two cats in the yard");
720 * StringBuffer sb = new StringBuffer();
721 * while (m.find()) {
722 * m.appendReplacement(sb, "dog");
723 * }
724 * m.appendTail(sb);
725 * System.out.println(sb.toString());</pre></blockquote>
726 *
727 * @param sb
728 * The target string buffer
729 *
730 * @param replacement
731 * The replacement string
732 *
733 * @return This matcher
734 *
735 * @throws IllegalStateException
736 * If no match has yet been attempted,
737 * or if the previous match operation failed
738 *
739 * @throws IllegalArgumentException
740 * If the replacement string refers to a named-capturing
741 * group that does not exist in the pattern
742 *
743 * @throws IndexOutOfBoundsException
744 * If the replacement string refers to a capturing group
745 * that does not exist in the pattern
746 */
747 public Matcher appendReplacement(StringBuffer sb, String replacement) {
748
749 // If no match, return error
750 if (first < 0)
751 throw new IllegalStateException("No match available");
752
753 // Process substitution string to replace group references with groups
754 int cursor = 0;
755 StringBuilder result = new StringBuilder();
756
757 while (cursor < replacement.length()) {
758 char nextChar = replacement.charAt(cursor);
759 if (nextChar == '\\') {
760 cursor++;
761 nextChar = replacement.charAt(cursor);
762 result.append(nextChar);
763 cursor++;
764 } else if (nextChar == '$') {
765 // Skip past $
766 cursor++;
767 // A StringIndexOutOfBoundsException is thrown if
768 // this "$" is the last character in replacement
769 // string in current implementation, a IAE might be
770 // more appropriate.
771 nextChar = replacement.charAt(cursor);
772 int refNum = -1;
773 if (nextChar == '<') {
774 cursor++;
775 StringBuilder gsb = new StringBuilder();
776 while (cursor < replacement.length()) {
777 nextChar = replacement.charAt(cursor);
778 if (ASCII.isLower(nextChar) ||
779 ASCII.isUpper(nextChar) ||
780 ASCII.isDigit(nextChar)) {
781 gsb.append(nextChar);
782 cursor++;
783 } else {
784 break;
785 }
786 }
787 if (gsb.length() == 0)
788 throw new IllegalArgumentException(
789 "named capturing group has 0 length name");
790 if (nextChar != '>')
791 throw new IllegalArgumentException(
792 "named capturing group is missing trailing '>'");
793 String gname = gsb.toString();
794 if (!parentPattern.namedGroups().containsKey(gname))
795 throw new IllegalArgumentException(
796 "No group with name <" + gname + ">");
797 refNum = parentPattern.namedGroups().get(gname);
798 cursor++;
799 } else {
800 // The first number is always a group
801 refNum = (int)nextChar - '0';
802 if ((refNum < 0)||(refNum > 9))
803 throw new IllegalArgumentException(
804 "Illegal group reference");
805 cursor++;
806 // Capture the largest legal group string
807 boolean done = false;
808 while (!done) {
809 if (cursor >= replacement.length()) {
810 break;
811 }
812 int nextDigit = replacement.charAt(cursor) - '0';
813 if ((nextDigit < 0)||(nextDigit > 9)) { // not a number
814 break;
815 }
816 int newRefNum = (refNum * 10) + nextDigit;
817 if (groupCount() < newRefNum) {
818 done = true;
819 } else {
820 refNum = newRefNum;
821 cursor++;
822 }
823 }
824 }
825 // Append group
826 if (start(refNum) != -1 && end(refNum) != -1)
827 result.append(text, start(refNum), end(refNum));
828 } else {
829 result.append(nextChar);
830 cursor++;
831 }
832 }
833 // Append the intervening text
834 sb.append(text, lastAppendPosition, first);
835 // Append the match substitution
836 sb.append(result);
837
838 lastAppendPosition = last;
839 return this;
840 }
841
842 /**
843 * Implements a terminal append-and-replace step.
844 *
|