--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/javax/management/DescriptorFields.java Wed Jul 09 10:36:07 2008 +0200
@@ -0,0 +1,137 @@
+/*
+ * Copyright 2007 Sun Microsystems, Inc. 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. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package javax.management;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * <p>Annotation that adds fields to a {@link Descriptor}. This can be the
+ * Descriptor for an MBean, or for an attribute, operation, or constructor
+ * in an MBean, or for a parameter of an operation or constructor.</p>
+ *
+ * <p>Consider this Standard MBean interface, for example:</p>
+ *
+ * <pre>
+ * public interface CacheControlMBean {
+ * <b>@DescriptorFields("units=bytes")</b>
+ * public long getCacheSize();
+ * }
+ * </pre>
+ *
+ * <p>When a Standard MBean is made using this interface, the usual rules
+ * mean that it will have an attribute called {@code CacheSize} of type
+ * {@code long}. The {@code DescriptorFields} annotation will ensure
+ * that the {@link MBeanAttributeInfo} for this attribute will have a
+ * {@code Descriptor} that has a field called {@code units} with
+ * corresponding value {@code bytes}.</p>
+ *
+ * <p>Similarly, if the interface looks like this:</p>
+ *
+ * <pre>
+ * public interface CacheControlMBean {
+ * <b>@DescriptorFields({"units=bytes", "since=1.5"})</b>
+ * public long getCacheSize();
+ * }
+ * </pre>
+ *
+ * <p>then the resulting {@code Descriptor} will contain the following
+ * fields:</p>
+ *
+ * <table border="2">
+ * <tr><th>Name</th><th>Value</th></tr>
+ * <tr><td>units</td><td>"bytes"</td></tr>
+ * <tr><td>since</td><td>"1.5"</td></tr>
+ * </table>
+ *
+ * <p>The {@code @DescriptorFields} annotation can be applied to:</p>
+ *
+ * <ul>
+ * <li>a Standard MBean or MXBean interface;
+ * <li>a method in such an interface;
+ * <li>a parameter of a method in a Standard MBean or MXBean interface
+ * when that method is an operation (not a getter or setter for an attribute);
+ * <li>a public constructor in the class that implements a Standard MBean
+ * or MXBean;
+ * <li>a parameter in such a constructor.
+ * </ul>
+ *
+ * <p>Other uses of the annotation will either fail to compile or be
+ * ignored.</p>
+ *
+ * <p>Interface annotations are checked only on the exact interface
+ * that defines the management interface of a Standard MBean or an
+ * MXBean, not on its parent interfaces. Method annotations are
+ * checked only in the most specific interface in which the method
+ * appears; in other words, if a child interface overrides a method
+ * from a parent interface, only {@code @DescriptorFields} annotations in
+ * the method in the child interface are considered.
+ *
+ * <p>The Descriptor fields contributed in this way must be consistent
+ * with each other and with any fields contributed by {@link
+ * DescriptorKey @DescriptorKey} annotations. That is, two
+ * different annotations, or two members of the same annotation, must
+ * not define a different value for the same Descriptor field. Fields
+ * from annotations on a getter method must also be consistent with
+ * fields from annotations on the corresponding setter method.</p>
+ *
+ * <p>The Descriptor resulting from these annotations will be merged
+ * with any Descriptor fields provided by the implementation, such as
+ * the <a href="Descriptor.html#immutableInfo">{@code
+ * immutableInfo}</a> field for an MBean. The fields from the annotations
+ * must be consistent with these fields provided by the implementation.</p>
+ *
+ * <h4>{@literal @DescriptorFields and @DescriptorKey}</h4>
+ *
+ * <p>The {@link DescriptorKey @DescriptorKey} annotation provides
+ * another way to use annotations to define Descriptor fields.
+ * <code>@DescriptorKey</code> requires more work but is also more
+ * robust, because there is less risk of mistakes such as misspelling
+ * the name of the field or giving an invalid value.
+ * <code>@DescriptorFields</code> is more convenient but includes
+ * those risks. <code>@DescriptorFields</code> is more
+ * appropriate for occasional use, but for a Descriptor field that you
+ * add in many places, you should consider a purpose-built annotation
+ * using <code>@DescriptorKey</code>.
+ *
+ * @since 1.7
+ */
+@Documented
+@Inherited // for @MBean and @MXBean classes
+@Target({ElementType.CONSTRUCTOR, ElementType.METHOD,
+ ElementType.PARAMETER, ElementType.TYPE})
+@Retention(RetentionPolicy.RUNTIME)
+public @interface DescriptorFields {
+ /**
+ * <p>The descriptor fields. Each element of the string looks like
+ * {@code "name=value"}.</p>
+ */
+ public String[] value();
+}