1 /*

     2  * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  */

    23 

    24 package jdk.experimental.bytecode;

    25 

    26 import java.util.Iterator;

    27 

    28 /**

    29  * Helper to create and manipulate type descriptors of T.

    30  *

    31  * @param <S> the type of symbols

    32  * @param <T> the type of type descriptors

    33  */

    34 public interface TypeHelper<S, T> {

    35     /**

    36      * Return the type descriptor of an element given the type

    37      * descriptor of an array.

    38      *

    39      * @param t the type descriptor of the array

    40      * @return the element type

    41      */

    42     T elemtype(T t);

    43 

    44     /**

    45      * Return the type descriptor of an array given the type descriptor

    46      * of an element.

    47      *

    48      * @param t the type descriptor of the element

    49      * @return the type descriptor of the array

    50      */

    51     T arrayOf(T t);

    52 

    53     /**

    54      * Return an iterator over the type descriptors of the parameters of a

    55      * method.

    56        *

    57      * @param t the method type descriptor

    58      * @return an iterator over the type descriptors of the parameters

    59      */

    60     Iterator<T> parameterTypes(T t);

    61 

    62     /**

    63      * Return the type descriptor of a {@code TypeTag}.

    64      *

    65      * @param tag the {@code TypeTag} of a primitive type

    66      * @return the type descriptor of the primitive type

    67      */

    68     T fromTag(TypeTag tag);

    69 

    70     /**

    71      * Return the return type descriptor of a method.

    72      *

    73      * @param t the method type descriptor

    74      * @return the return type descriptor

    75      */

    76     T returnType(T t);

    77 

    78     /**

    79      * Return the type descriptor for a symbol.

    80      *

    81      * @param s the symbol

    82      * @return the type descriptor

    83      */

    84     T type(S s);

    85 

    86     /**

    87      * Return the symbol corresponding to a type descriptor.

    88      *

    89      * @param type the type descriptor

    90      * @return the symbol

    91      */

    92     S symbol(T type);

    93 

    94     /**

    95      * Return the {@code TypeTag} corresponding to a type descriptor.  Reference

    96      * types return {@code TypeTag.A}.

    97      *

    98      * @param t a type descriptor

    99      * @return the corresponding {@code TypeTag}

   100      */

   101     TypeTag tag(T t);

   102 

   103     /**

   104      * Return the symbol corresponding to a JVM type descriptor string.

   105      *

   106      * @param s a JVM type descriptor string

   107      * @return the corresponding symbol

   108      */

   109     S symbolFrom(String s);

   110 

   111     /**

   112      * Return the common supertype descriptor of two type descriptors.

   113      *

   114      * @param t1 a type descriptor

   115      * @param t2 a type descriptor

   116      * @return the common supertype descriptor

   117      */

   118     T commonSupertype(T t1, T t2);

   119 

   120     /**

   121      * Return the type descriptor for the null type.

   122      *

   123      * @return the type descriptor for the null type

   124      */

   125     T nullType();

   126 }