Mercurial > hg > truffle
diff truffle/com.oracle.truffle.api.dsl/src/com/oracle/truffle/api/dsl/TypeCast.java @ 21951:9c8c0937da41
Moving all sources into truffle subdirectory
author | Jaroslav Tulach <jaroslav.tulach@oracle.com> |
---|---|
date | Wed, 17 Jun 2015 10:58:08 +0200 |
parents | graal/com.oracle.truffle.api.dsl/src/com/oracle/truffle/api/dsl/TypeCast.java@3ea386a1036f |
children | dc83cc1f94f2 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/truffle/com.oracle.truffle.api.dsl/src/com/oracle/truffle/api/dsl/TypeCast.java Wed Jun 17 10:58:08 2015 +0200 @@ -0,0 +1,55 @@ +/* + * Copyright (c) 2012, 2012, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. Oracle designates this + * particular file as subject to the "Classpath" exception as provided + * by Oracle in the LICENSE file that accompanied this code. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + */ +package com.oracle.truffle.api.dsl; + +import java.lang.annotation.*; + +/** + * Overrides the standard way of casting a certain type in a {@link TypeSystem}. This is useful for + * types where the guest language specific type cast can be implemented more efficiently than an + * instanceof check. The annotated method must be contained in a {@link TypeSystem} annotated class. + * Type checks must conform to the following signature: <code>public static Type as{TypeName}(Object + * value)</code>. The casted type must be a type declared in the {@link TypeSystem}. + * + * <p> + * If no {@link TypeCast} is declared then the type system implicitly uses a type cast that can be + * declared as follows: + * + * <pre> + * {@literal @}TypeCast(Type.class) + * public static Type asType(Object value) { + * return (Type) value; + * } + * </pre> + * + * @see TypeCheck + */ +@Retention(RetentionPolicy.CLASS) +@Target({ElementType.METHOD}) +public @interface TypeCast { + + Class<?> value(); + +}