Examples of java.util.regex.Matcher.appendReplacement()

• java.util.regex.Matcher.appendReplacement()
  Implements a non-terminal append-and-replace step.

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

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

  The replacement string may contain references to subsequences captured during the previous match: Each occurrence of $g will be replaced by the result of evaluating {@link #group(int) group}(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. Thefollowing 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 IndexOutOfBoundsException If the replacement string refers to a capturing group that does not exist in the pattern