Class Pattern

java/com/google/re2j/Pattern.java:30–362

A compiled representation of an RE2 regular expression, mimicking the java.util.regex.Pattern API. The matching functions take String arguments instead of the more general Java CharSequence since the latter doesn't provide UTF-16 decoding. See the <a href='package.h

 * @author rsc@google.com (Russ Cox)
 */
public final class Pattern implements Serializable {
  /** Flag: case insensitive matching. */
  public static final int CASE_INSENSITIVE = 1;

  /** Flag: dot ({@code .}) matches all characters, including newline. */
  public static final int DOTALL = 2;

  /**
   * Flag: multiline matching: {@code ^} and {@code $} match at beginning and end of line, not just
   * beginning and end of input.
   */
  public static final int MULTILINE = 4;

  /**
   * Flag: Unicode groups (e.g. {@code \p\ Greek\} ) will be syntax errors.
   */
  public static final int DISABLE_UNICODE_GROUPS = 8;

  /**
   * Flag: matches longest possible string.
   */
  public static final int LONGEST_MATCH = 16;

  // The pattern string at construction time.
  private final String pattern;

  // The flags at construction time.
  private final int flags;

  // The compiled RE2 regexp.
  private transient final RE2 re2;

  // This is visible for testing.
  Pattern(String pattern, int flags, RE2 re2) {
    if (pattern == null) {
      throw new NullPointerException("pattern is null");
    }
    if (re2 == null) {
      throw new NullPointerException("re2 is null");
    }
    this.pattern = pattern;
    this.flags = flags;
    this.re2 = re2;
  }

  /**
   * Releases memory used by internal caches associated with this pattern. Does not change the
   * observable behaviour. Useful for tests that detect memory leaks via allocation tracking.
   */
  public void reset() {
    re2.reset();
  }

  /**
   * Returns the flags used in the constructor.
   */
  public int flags() {
    return flags;