| /* |
| * Copyright (c) 1997, 2021 Oracle and/or its affiliates. All rights reserved. |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Distribution License v. 1.0, which is available at |
| * http://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| */ |
| |
| package org.glassfish.jaxb.core.annotation; |
| |
| import java.lang.annotation.Retention; |
| import java.lang.annotation.Target; |
| |
| import jakarta.xml.bind.annotation.XmlAttribute; |
| import jakarta.xml.bind.annotation.XmlElement; |
| import jakarta.xml.bind.annotation.XmlElementRef; |
| import jakarta.xml.bind.annotation.XmlValue; |
| |
| import static java.lang.annotation.ElementType.FIELD; |
| import static java.lang.annotation.ElementType.METHOD; |
| import static java.lang.annotation.RetentionPolicy.RUNTIME; |
| |
| /** |
| * Designates a boolean field/property as a flag to indicate |
| * whether another property is present or not. |
| * |
| * <p> |
| * Sometimes you'd want to map a Java primitive type to an |
| * optional element/attribute. Doing this makes it impossible |
| * to represent the absence of the property, thus you always |
| * end up producing the value when you marshal to XML. |
| * |
| * For example, |
| * <pre> |
| * {@link XmlElement} |
| * class Foo { |
| * {@link XmlElement} |
| * int x; |
| * } |
| * |
| * marshaller.marshal(new Foo()); |
| * </pre> |
| * and you get: |
| * <pre>{@code |
| * <foo><x>0</x></foo> |
| * }</pre> |
| * |
| * <p> |
| * By creating a side boolean field/property that has this annotation, |
| * you can indicate the absence of the property by setting this boolean |
| * to false. |
| * <pre> |
| * {@link XmlElement} |
| * class Foo { |
| * {@link XmlElement} |
| * int x; |
| * {@link XmlIsSet}("x") |
| * boolean xIsPresent; |
| * } |
| * |
| * Foo f = new Foo(); |
| * f.x = 5; |
| * f.xIsPresent = false; |
| * |
| * marshaller.marshal(f); |
| * |
| * {@code |
| * <foo/> |
| * } |
| * |
| * f.xIsPresent = true; |
| * {@code |
| * <foo><x>5</x></foo> |
| * } |
| * </pre> |
| * |
| * <p> |
| * A property/field annotated with {@link XmlIsSet} itself will not show up in XML. |
| * It is an error to use this annotation on the same property/field |
| * as {@link XmlElement}, {@link XmlAttribute}, {@link XmlValue}, or {@link XmlElementRef}, |
| * ...<b>TBD</b>. |
| * |
| * @deprecated |
| * this hasn't been implemented in the RI, and this hasn't been speced yet. |
| * I believe Joe asked for this feature. I'd like to drop this. |
| * |
| * @author Kohsuke Kawaguchi |
| */ |
| @Retention(RUNTIME) |
| @Target({FIELD,METHOD}) |
| public @interface XmlIsSet { |
| /** |
| * Specifies the name of the property to attach to. |
| */ |
| String value(); |
| } |