001    /*
002     * Copyright 2005-2006 Sun Microsystems, Inc.  All Rights Reserved.
003     * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004     *
005     * This code is free software; you can redistribute it and/or modify it
006     * under the terms of the GNU General Public License version 2 only, as
007     * published by the Free Software Foundation.  Sun designates this
008     * particular file as subject to the "Classpath" exception as provided
009     * by Sun in the LICENSE file that accompanied this code.
010     *
011     * This code is distributed in the hope that it will be useful, but WITHOUT
012     * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013     * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
014     * version 2 for more details (a copy is included in the LICENSE file that
015     * accompanied this code).
016     *
017     * You should have received a copy of the GNU General Public License version
018     * 2 along with this work; if not, write to the Free Software Foundation,
019     * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020     *
021     * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022     * CA 95054 USA or visit www.sun.com if you need additional information or
023     * have any questions.
024     */
025    
026    package javax.lang.model.type;
027    
028    
029    import javax.lang.model.element.Element;
030    import javax.lang.model.element.TypeParameterElement;
031    import javax.lang.model.util.Types;
032    
033    
034    /**
035     * Represents a type variable.
036     * A type variable may be explicitly declared by a
037     * {@linkplain TypeParameterElement type parameter} of a
038     * type, method, or constructor.
039     * A type variable may also be declared implicitly, as by
040     * the capture conversion of a wildcard type argument
041     * (see chapter 5 of <i>The Java Language Specification, Third
042     * Edition</i>).
043     *
044     * @author Joseph D. Darcy
045     * @author Scott Seligman
046     * @author Peter von der Ah&eacute;
047     * @see TypeParameterElement
048     * @since 1.6
049     */
050    public interface TypeVariable extends ReferenceType {
051    
052        /**
053         * Returns the element corresponding to this type variable.
054         *
055         * @return the element corresponding to this type variable
056         */
057        Element asElement();
058    
059        /**
060         * Returns the upper bound of this type variable.
061         *
062         * <p> If this type variable was declared with no explicit
063         * upper bounds, the result is {@code java.lang.Object}.
064         * If it was declared with multiple upper bounds,
065         * the result is an intersection type (modeled as a
066         * {@link DeclaredType}).
067         * Individual bounds can be found by examining the result's
068         * {@linkplain Types#directSupertypes(TypeMirror) supertypes}.
069         *
070         * @return the upper bound of this type variable
071         */
072        TypeMirror getUpperBound();
073    
074        /**
075         * Returns the lower bound of this type variable.  While a type
076         * parameter cannot include an explicit lower bound declaration,
077         * capture conversion can produce a type variable with a
078         * non-trivial lower bound.  Type variables otherwise have a
079         * lower bound of {@link NullType}.
080         *
081         * @return the lower bound of this type variable
082         */
083        TypeMirror getLowerBound();
084    }