| /* |
| * Copyright (c) 2012, 2013, 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.invoke; |
| |
| import java.lang.annotation.*; |
| |
| /** |
| * A field may be annotated as stable if all of its component variables |
| * changes value at most once. |
| * A field's value counts as its component value. |
| * If the field is typed as an array, then all the non-null components |
| * of the array, of depth up to the rank of the field's array type, |
| * also count as component values. |
| * By extension, any variable (either array or field) which has annotated |
| * as stable is called a stable variable, and its non-null or non-zero |
| * value is called a stable value. |
| * <p> |
| * Since all fields begin with a default value of null for references |
| * (resp., zero for primitives), it follows that this annotation indicates |
| * that the first non-null (resp., non-zero) value stored in the field |
| * will never be changed. |
| * <p> |
| * If the field is not of an array type, there are no array elements, |
| * then the value indicated as stable is simply the value of the field. |
| * If the dynamic type of the field value is an array but the static type |
| * is not, the components of the array are <em>not</em> regarded as stable. |
| * <p> |
| * If the field is an array type, then both the field value and |
| * all the components of the field value (if the field value is non-null) |
| * are indicated to be stable. |
| * If the field type is an array type with rank {@code N > 1}, |
| * then each component of the field value (if the field value is non-null), |
| * is regarded as a stable array of rank {@code N-1}. |
| * <p> |
| * Fields which are declared {@code final} may also be annotated as stable. |
| * Since final fields already behave as stable values, such an annotation |
| * indicates no additional information, unless the type of the field is |
| * an array type. |
| * <p> |
| * It is (currently) undefined what happens if a field annotated as stable |
| * is given a third value. In practice, if the JVM relies on this annotation |
| * to promote a field reference to a constant, it may be that the Java memory |
| * model would appear to be broken, if such a constant (the second value of the field) |
| * is used as the value of the field even after the field value has changed. |
| */ |
| /* package-private */ |
| @Target(ElementType.FIELD) |
| @Retention(RetentionPolicy.RUNTIME) |
| @interface Stable { |
| } |