--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.api.dsl/src/com/oracle/truffle/api/dsl/TypeCheck.java	Mon Jul 01 20:58:32 2013 +0200
@@ -0,0 +1,80 @@
+/*
+ * 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.
+ *
+ * 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.*;
+
+/**
+ * <p>
+ * Provides a way to define a custom type check for a defined type. The name of the annotated method
+ * must fit to the pattern is${typeName} (eg. isInteger), where ${typeName} must be a valid type
+ * defined in the parent {@link TypeSystem}. The annotated method must have exactly one argument
+ * where the type of the argument is the generic type {@link Object} or a more specific one from the
+ * {@link TypeSystem}. You can define multiple overloaded {@link TypeCheck} methods for the same
+ * type. This can be used to reduce the boxing overhead in type conversions.
+ * </p>
+ * 
+ * <p>
+ * By default the system generates type checks for all types in the parent {@link TypeSystem} which
+ * look like the follows:
+ * 
+ * <pre>
+ * {@literal @}TypeCheck
+ * boolean is${typeName}(Object value) {
+ *         return value instanceof ${typeName};
+ * }
+ * </pre>
+ * 
+ * </p>
+ * 
+ * <b>Example:</b>
+ * <p>
+ * A type check for BigInteger with one overloaded optimized variant to reduce boxing.
+ * </p>
+ * 
+ * <pre>
+ * 
+ * 
+ * {@literal @}TypeSystem(types = {int.class, BigInteger.class, String.class}, nodeBaseClass = TypedNode.class)
+ * public abstract class Types {
+ * 
+ *     {@literal @}TypeCheck
+ *     public boolean isBigInteger(Object value) {
+ *         return value instanceof Integer || value instanceof BigInteger;
+ *     }
+ * 
+ *     {@literal @}TypeCheck
+ *     public boolean isBigInteger(int value) {
+ *         return true;
+ *     }
+ * 
+ * }
+ * </pre>
+ * 
+ * 
+ */
+@Retention(RetentionPolicy.CLASS)
+@Target({ElementType.METHOD})
+public @interface TypeCheck {
+
+}