| /* |
| * Copyright (c) 2010, 2015, 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} nor {@code private}. |
| * |
| * </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. Some unsafe operations do not trigger an unchecked |
| * warning. For example, the aliasing in |
| * |
| * <blockquote><pre> |
| * @SafeVarargs // Not actually safe! |
| * static void m(List<String>... stringLists) { |
| * Object[] array = stringLists; |
| * List<Integer> tmpList = Arrays.asList(42); |
| * array[0] = tmpList; // Semantically invalid, but compiles without warnings |
| * String s = stringLists[0].get(0); // Oh no, ClassCastException at runtime! |
| * } |
| * </pre></blockquote> |
| * |
| * leads to a {@code ClassCastException} at runtime. |
| * |
| * <p>Future versions of the platform may mandate compiler errors for |
| * such unsafe operations. |
| * |
| * </ul> |
| * |
| * @since 1.7 |
| * @jls 4.7 Reifiable Types |
| * @jls 8.4.1 Formal Parameters |
| * @jls 9.6.4.7 @SafeVarargs |
| */ |
| @Documented |
| @Retention(RetentionPolicy.RUNTIME) |
| @Target({ElementType.CONSTRUCTOR, ElementType.METHOD}) |
| public @interface SafeVarargs {} |