checker/tests/interning/PrimitivesInterning.java

import java.util.HashMap;
import java.util.Map;
import org.checkerframework.checker.interning.qual.*;

public class PrimitivesInterning {

  void test() {
    int a = 3;

    if (a == 3) {
      System.out.println("yes");
    } else {
      System.out.println("no");
    }

    if (a != 2) {
      System.out.println("yes");
    } else {
      System.out.println("no");
    }

    String name = "Interning";
    if ((name.indexOf('[') == -1) && (name.indexOf('(') == -1)) {
      System.out.println("has no open punctuation");
    } else {
      System.out.println("has open punctuation");
    }

    Number n = Integer.valueOf(22);
    boolean is_double = (n instanceof Double); // valid

    int index = 0;
    index = Integer.decode("22"); // valid: auto-unboxing conversion

    // auto-unboxing conversion again
    Map<String, Integer> m = new HashMap<>();
    if (m.get("hello") == 22) {
      System.out.println("hello maps to 22");
    }
  }

  public static int pow_fast(int base, int expt) throws ArithmeticException {
    if (expt < 0) {
      throw new ArithmeticException("Negative base passed to pow");
    }

    int this_square_pow = base;
    int result = 1;
    while (expt > 0) {
      if ((expt & 1) != 0) {
        result *= this_square_pow;
      }
      expt >>= 1;
      this_square_pow *= this_square_pow;
    }
    return result;
  }

  /** Return the greatest common divisor of the two arguments. */
  public static int gcd(int a, int b) {

    // Euclid's method
    if (b == 0) {
      return (Math.abs(a));
    }
    a = Math.abs(a);
    b = Math.abs(b);
    while (b != 0) {
      int tmp = b;
      b = a % b;
      a = tmp;
    }
    return a;
  }

  /** Return the greatest common divisor of the elements of int array a. */
  public static int gcd(int[] a) {
    // Euclid's method
    if (a.length == 0) {
      return 0;
    }
    int result = a[0];
    for (int i = 1; i < a.length; i++) {
      result = gcd(a[i], result);
      if ((result == 1) || (result == 0)) {
        return result;
      }
    }
    return result;
  }

  /**
   * Return the gcd (greatest common divisor) of the differences between the elements of int array
   * a.
   */
  public static int gcd_differences(int[] a) {
    // Euclid's method
    if (a.length < 2) {
      return 0;
    }
    int result = a[1] - a[0];
    for (int i = 2; i < a.length; i++) {
      result = gcd(a[i] - a[i - 1], result);
      if ((result == 1) || (result == 0)) {
        return result;
      }
    }
    return result;
  }

  void compounds() {
    int res = 0;
    res += 5;
    res /= 9;
  }

  // TODO: enable after boxing is improved in AST creation
  // void negation() {
  //   Boolean t = new Boolean(true);
  //   boolean b = !t;
  // }

}