@Override
  public abstract String toString();

  public static CommonPattern compile(String pattern) {
    return Platform.compilePattern(pattern);
  }

  public static boolean isPcreLike() {
    return Platform.patternCompilerIsPcreLike();
  }

   */
  @RestrictedApi(
      explanation = "PatternCompiler is an implementation detail of com.google.common.base",
      allowedOnPath = ".*/com/google/common/base/.*")
  boolean isPcreLike();

   */
  @RestrictedApi(
      explanation = "PatternCompiler is an implementation detail of com.google.common.base",
      allowedOnPath = ".*/com/google/common/base/.*")
  boolean isPcreLike();

  @Override
  public abstract String toString();

  public static CommonPattern compile(String pattern) {
    return Platform.compilePattern(pattern);
  }

  public static boolean isPcreLike() {
    return Platform.patternCompilerIsPcreLike();
  }

  static CommonPattern compilePattern(String pattern) {
    Preconditions.checkNotNull(pattern);
    return patternCompiler.compile(pattern);
  }

  static boolean patternCompilerIsPcreLike() {
    return patternCompiler.isPcreLike();
  }

  private static PatternCompiler loadPatternCompiler() {
    return new JdkPatternCompiler();
  }

  private static final class JdkPatternCompiler implements PatternCompiler {
    @Override

  static CommonPattern compilePattern(String pattern) {
    Preconditions.checkNotNull(pattern);
    return patternCompiler.compile(pattern);
  }

  static boolean patternCompilerIsPcreLike() {
    return patternCompiler.isPcreLike();
  }

  private static PatternCompiler loadPatternCompiler() {
    // We want the JDK Pattern compiler:
    // - under Android (where it hurts startup performance)

  @GwtIncompatible // java.util.regex.Pattern
  @AndroidIncompatible // Bug in older versions of Android we test against, since fixed.
  public void testPatternSplitLookBehind() {
    if (!CommonPattern.isPcreLike()) {
      return;
    }
    String toSplit = ":foo::barbaz:";
    String regexPattern = "(?<=:)";
    Iterable<String> split = Splitter.onPattern(regexPattern).split(toSplit);