abstractstringmatcher.java

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// Introduced in Chapter 13
/** Searches for a pattern String in various text Strings. */
public abstract class AbstractStringMatcher {

  /** The pattern being sought. */
  private String pattern;

  /** Pattern is the pattern being sought. */
  public AbstractStringMatcher(String pattern) {
    this.pattern = pattern;
  }

  /** Return the pattern this StringMatcher seeks. */
  protected String getPattern() {
    return pattern;
  }

  /** Return true if the pattern appears in text at position. */
  protected boolean matchAt(String text, int position) {
    for (int i = 0; i < pattern.length(); i++) {
      if (pattern.charAt(i) != text.charAt(i + position)) {
        return false;
      }
    }
    return true;
  }

  /**
   * Return the index of the first appearance of the pattern in
   * text, or -1 if it does not appear.
   */
  public abstract int match(String text);

}