7006129: Project Coin: Annotation type to reduce varargs warnings

Reviewed-by: jjg, mcimadamore

jdk/make/java/java/FILES_java.gmk

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 1996, 2008, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 1996, 2010, 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
@@ -137,6 +137,7 @@ JAVA_JAVA_java = \
     java/lang/Comparable.java \
     java/lang/Readable.java \
     java/lang/Override.java \
+    java/lang/SafeVarargs.java \
     java/lang/SuppressWarnings.java \
     java/lang/ref/Reference.java \
         java/lang/ref/SoftReference.java \

jdk/src/share/classes/java/lang/SafeVarargs.java

@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2010, 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 java.lang;
+
+import java.lang.annotation.*;
+
+/**
+ * A programmer assertion that the body of the annotated method or
+ * constructor does not perform potentially unsafe operations on its
+ * varargs parameter.  Applying this annotation to a method or
+ * constructor suppresses unchecked warnings about a
+ * <i>non-reifiable</i> variable-arity (vararg) type and suppresses
+ * unchecked warnings about parameterized array creation at call
+ * sites.
+ *
+ * <p> In addition to the usage restrictions imposed by its {@link
+ * Target @Target} meta-annotation, compilers are required to implement
+ * additional usage restrictions on this annotation type; it is a
+ * compile-time error if a method or constructor declaration is
+ * annotated with a {@code @SafeVarargs} annotation, and either:
+
+ * <ul>
+ * <li>  the declaration is a fixed-arity method or constructor
+ *
+ * <li> the declaration is a variable-arity method that is neither
+ * {@code static} nor {@code final}.
+ *
+ * </ul>
+ *
+ * <p> Compilers are encouraged to issue warnings when this annotation
+ * type is applied to a method or constructor declaration where:
+ *
+ * <ul>
+ *
+ * <li> The variable-arity parameter has a reifiable element type,
+ * which includes primitive types, {@code Object}, and {@code String}.
+ * (The unchecked warnings this annotation type suppresses already do
+ * not occur for a reifiable element type.)
+ *
+ * <li> The body of the method or constructor declaration performs
+ * potentially unsafe operations, such as an assignment to an element
+ * of the variable-arity parameter's array that generates an unchecked
+ * warning.
+ *
+ * <p>Future versions of the platform may mandate compiler errors for
+ * such unsafe operations.
+ *
+ * </ul>
+ *
+ * @jls3 4.7 Reifiable Types
+ * @jls3 8.4.1 Formal Parameters
+ */
+@Documented
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ElementType.CONSTRUCTOR, ElementType.METHOD})
+public @interface SafeVarargs {}