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package javax.lang.model.type;


import javax.lang.model.element.Element;
import javax.lang.model.element.TypeParameterElement;
import javax.lang.model.util.Types;


Represents a type variable. A type variable may be explicitly declared by a type parameter of a type, method, or constructor. A type variable may also be declared implicitly, as by the capture conversion of a wildcard type argument (see chapter 5 of The Java Language Specification).
Author:
Joseph D. Darcy, Scott Seligman, Peter von der Ahé
See Also:
TypeParameterElement
Since:
1.6/**
 * Represents a type variable.
 * A type variable may be explicitly declared by a
 * {@linkplain TypeParameterElement type parameter} of a
 * type, method, or constructor.
 * A type variable may also be declared implicitly, as by
 * the capture conversion of a wildcard type argument
 * (see chapter 5 of
 * <cite>The Java Language Specification</cite>).
 *
 * @author Joseph D. Darcy
 * @author Scott Seligman
 * @author Peter von der Ah&eacute;
 * @see TypeParameterElement
 * @since 1.6
 */
public interface TypeVariable extends ReferenceType {

    
Returns the element corresponding to this type variable.
Returns:
the element corresponding to this type variable/**
     * Returns the element corresponding to this type variable.
     *
     * @return the element corresponding to this type variable
     */
    Element asElement();

    
Returns the upper bound of this type variable.
 If this type variable was declared with no explicit upper bounds, the result is java.lang.Object. If it was declared with multiple upper bounds, the result is an intersection type; individual bounds can be found by examining the result's bounds. 
Returns:
the upper bound of this type variable/**
     * Returns the upper bound of this type variable.
     *
     * <p> If this type variable was declared with no explicit
     * upper bounds, the result is {@code java.lang.Object}.
     * If it was declared with multiple upper bounds,
     * the result is an {@linkplain IntersectionType intersection type};
     * individual bounds can be found by examining the result's
     * {@linkplain IntersectionType#getBounds() bounds}.
     *
     * @return the upper bound of this type variable
     */
    TypeMirror getUpperBound();

    
Returns the lower bound of this type variable. While a type parameter cannot include an explicit lower bound declaration, capture conversion can produce a type variable with a non-trivial lower bound. Type variables otherwise have a lower bound of NullType. 
Returns:
the lower bound of this type variable/**
     * Returns the lower bound of this type variable.  While a type
     * parameter cannot include an explicit lower bound declaration,
     * capture conversion can produce a type variable with a
     * non-trivial lower bound.  Type variables otherwise have a
     * lower bound of {@link NullType}.
     *
     * @return the lower bound of this type variable
     */
    TypeMirror getLowerBound();
}