Source for java.lang.reflect.WildcardType

   1: /* WildcardType.java -- A wildcard type expression e.g. ? extends String
   2:    Copyright (C) 2004, 2005 Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package java.lang.reflect;
  40: 
  41: /**
  42:  * Represents a wildcard type expression, where the type variable
  43:  * is unnamed.  The simplest example of this is <code>?</code>,
  44:  * which represents any unbounded type.  Another example is
  45:  * <code>? extends Number</code>, which specifies any type
  46:  * which is a subclass of <code>Number</code> (<code>Number</code>
  47:  * is the upper bound).
  48:  * </p>
  49:  * <p>
  50:  * <code>? super String</code> gives the type a less common lower bound,
  51:  * which means that the type must be either a <code>String</code> or one
  52:  * of its superclasses. This can be useful in working with collections.
  53:  * You may want a method to add instances of a class to a collection
  54:  * with a more generic type (e.g. adding <code>String</code>s to
  55:  * a list of <code>Object</code>s), but don't want to allow users
  56:  * to pass in a collection with a more specific type.
  57:  * </p>
  58:  *
  59:  * @author Tom Tromey (tromey@redhat.com)
  60:  * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
  61:  * @since 1.5
  62:  */
  63: public interface WildcardType extends Type
  64: {
  65: 
  66:   /**
  67:    * <p>
  68:    * Returns an array of <code>Type</code>s, which specify the
  69:    * lower bounds of this type.  The default lower bound is
  70:    * <code>null</code>, which causes this method to return an
  71:    * empty array.
  72:    * </p>
  73:    * <p>
  74:    * In generating the array of <code>Type</code>s, each
  75:    * <code>ParameterizedType</code> or <code>TypeVariable</code> is
  76:    * created, (see the documentation for these classes for details of this
  77:    * process), if necessary, while all other types are simply
  78:    * resolved.
  79:    * </p>
  80:    *
  81:    * @return an array of <code>Type</code> objects, representing
  82:    *         the wildcard type's lower bounds.
  83:    * @throws TypeNotPresentException if any of the types referred to by
  84:    *         the lower bounds of this type do not actually exist.
  85:    * @throws MalformedParameterizedTypeException if any of the types
  86:    *         refer to a type which can not be instantiated.
  87:    */
  88:   Type[] getLowerBounds();
  89: 
  90:   /**
  91:    * <p>
  92:    * Returns an array of <code>Type</code>s, which specify the
  93:    * upper bounds of this type.  The default upper bound is
  94:    * <code>Object</code>, which causes this method to return an
  95:    * array, containing just the <code>Type</code> instance for
  96:    * <code>Object</code>.
  97:    * </p>
  98:    * <p>
  99:    * In generating the array of <code>Type</code>s, each
 100:    * <code>ParameterizedType</code> or <code>TypeVariable</code> is
 101:    * created, (see the documentation for these classes for details of this
 102:    * process), if necessary, while all other types are simply
 103:    * resolved.
 104:    * </p>
 105:    *
 106:    * @return an array of <code>Type</code> objects, representing
 107:    *         the wildcard type's upper bounds.
 108:    * @throws TypeNotPresentException if any of the types referred to by
 109:    *         the upper bounds of this type do not actually exist.
 110:    * @throws MalformedParameterizedTypeException if any of the types
 111:    *         refer to a type which can not be instantiated.
 112:    */
 113:   Type[] getUpperBounds();
 114: 
 115: }