checker-qual/src/main/java/org/checkerframework/framework/qual/LiteralKind.java

package org.checkerframework.framework.qual;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * Specifies kinds of literal trees.
 *
 * <p>These correspond to the *_LITERAL constants in {@link com.sun.source.tree.Tree.Kind}. However,
 * that enum is in the tools.jar which is not on the user's classpath by default. This enum is used
 * by meta-annotations, such as {@link QualifierForLiterals}, instead.
 */
// https://docs.oracle.com/javase/8/docs/technotes/tools/findingclasses.html#bootclass
public enum LiteralKind {
  /** Corresponds to {@link com.sun.source.tree.Tree.Kind#NULL_LITERAL} trees. */
  NULL,
  /** Corresponds to {@link com.sun.source.tree.Tree.Kind#INT_LITERAL} trees. */
  INT,
  /** Corresponds to {@link com.sun.source.tree.Tree.Kind#LONG_LITERAL} trees. */
  LONG,
  /** Corresponds to {@link com.sun.source.tree.Tree.Kind#FLOAT_LITERAL} trees. */
  FLOAT,
  /** Corresponds to {@link com.sun.source.tree.Tree.Kind#DOUBLE_LITERAL} trees. */
  DOUBLE,
  /** Corresponds to {@link com.sun.source.tree.Tree.Kind#BOOLEAN_LITERAL} trees. */
  BOOLEAN,
  /** Corresponds to {@link com.sun.source.tree.Tree.Kind#CHAR_LITERAL} trees. */
  CHAR,
  /** Corresponds to {@link com.sun.source.tree.Tree.Kind#STRING_LITERAL} trees. */
  STRING,
  /** Shorthand for all other LiteralKind constants, other than PRIMITIVE. */
  ALL,
  /** Shorthand for all primitive LiteralKind constants: INT, LONG, FLOAT, DOUBLE, BOOLEAN, CHAR. */
  PRIMITIVE;

  /**
   * Returns all LiteralKinds except for ALL and PRIMITIVE (which are shorthands for groups of other
   * LiteralKinds).
   *
   * @return list of LiteralKinds except for ALL and PRIMITIVE
   */
  public static List<LiteralKind> allLiteralKinds() {
    List<LiteralKind> list = new ArrayList<>(Arrays.asList(values()));
    list.remove(ALL);
    list.remove(PRIMITIVE);
    return list;
  }

  /**
   * Returns the primitive {@code LiteralKind}s: INT, LONG, FLOAT, DOUBLE, BOOLEAN, CHAR. This is
   * all LiteralKinds except for NULL, STRING, and ones that are shorthands for groups of other
   * LiteralKinds.
   *
   * @return list of LiteralKinds except for NULL and STRING
   */
  public static List<LiteralKind> primitiveLiteralKinds() {
    return Arrays.asList(INT, LONG, FLOAT, DOUBLE, BOOLEAN, CHAR);
  }
}