org.checkerframework.framework.util.element.ClassTypeParamApplier Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of checker Show documentation

The Checker Framework enhances Java's type system to make it more powerful and useful. This lets software developers detect and prevent errors in their Java programs. The Checker Framework includes compiler plug-ins ("checkers") that find bugs or verify their absence. It also permits you to write your own compiler plug-ins.

There is a newer version: 3.44.0

Show newest version

package org.checkerframework.framework.util.element;

import com.sun.tools.javac.code.Attribute;
import com.sun.tools.javac.code.Symbol;
import com.sun.tools.javac.code.TargetType;
import javax.lang.model.element.Element;
import javax.lang.model.element.ElementKind;
import org.checkerframework.framework.type.AnnotatedTypeFactory;
import org.checkerframework.framework.type.AnnotatedTypeMirror;
import org.checkerframework.framework.type.AnnotatedTypeMirror.AnnotatedTypeVariable;
import org.checkerframework.framework.util.element.ElementAnnotationUtil.UnexpectedAnnotationLocationException;
import org.checkerframework.javacutil.BugInCF;

/**
 * Applies the annotations present for a class type parameter onto an AnnotatedTypeVariable. See
 * {@link TypeParamElementAnnotationApplier} for details.
 */
public class ClassTypeParamApplier extends TypeParamElementAnnotationApplier {

  /** Apply annotations from {@code element} to {@code type}. */
  public static void apply(
      AnnotatedTypeVariable type, Element element, AnnotatedTypeFactory typeFactory)
      throws UnexpectedAnnotationLocationException {
    new ClassTypeParamApplier(type, element, typeFactory).extractAndApply();
  }

  /**
   * Returns true if element represents a type parameter for a class.
   *
   * @param type ignored
   * @param element the element that might be a type parameter
   * @return true if element represents a type parameter for a class
   */
  public static boolean accepts(final AnnotatedTypeMirror type, final Element element) {
    return element.getKind() == ElementKind.TYPE_PARAMETER
        && element.getEnclosingElement() instanceof Symbol.ClassSymbol;
  }

  /** The class that holds the type parameter element. */
  private final Symbol.ClassSymbol enclosingClass;

  ClassTypeParamApplier(
      AnnotatedTypeVariable type, Element element, AnnotatedTypeFactory typeFactory) {
    super(type, element, typeFactory);

    if (!(element.getEnclosingElement() instanceof Symbol.ClassSymbol)) {
      throw new BugInCF(
          "TypeParameter not enclosed by class?  Type( "
              + type
              + " ) "
              + "Element ( "
              + element
              + " ) ");
    }

    enclosingClass = (Symbol.ClassSymbol) element.getEnclosingElement();
  }

  /**
   * Returns TargetType.CLASS_TYPE_PARAMETER.
   *
   * @return TargetType.CLASS_TYPE_PARAMETER
   */
  @Override
  protected TargetType lowerBoundTarget() {
    return TargetType.CLASS_TYPE_PARAMETER;
  }

  /**
   * Returns TargetType.CLASS_TYPE_PARAMETER_BOUND.
   *
   * @return TargetType.CLASS_TYPE_PARAMETER_BOUND
   */
  @Override
  protected TargetType upperBoundTarget() {
    return TargetType.CLASS_TYPE_PARAMETER_BOUND;
  }

  /**
   * Returns the index of element in the type parameter list of its enclosing class.
   *
   * @return the index of element in the type parameter list of its enclosing class
   */
  @Override
  public int getElementIndex() {
    return enclosingClass.getTypeParameters().indexOf(element);
  }

  @Override
  protected TargetType[] validTargets() {
    return new TargetType[] {TargetType.CLASS_EXTENDS};
  }

  /**
   * Returns the raw type attributes of the enclosing class.
   *
   * @return the raw type attributes of the enclosing class
   */
  @Override
  protected Iterable getRawTypeAttributes() {
    return enclosingClass.getRawTypeAttributes();
  }

  @Override
  protected boolean isAccepted() {
    return accepts(type, element);
  }
}