/* * Copyright (c) 2005, 2006, 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 javax.management.openmbean; /** * <p>A Java class can implement this interface to indicate how it is * to be converted into a {@code CompositeData} by the MXBean framework.</p> * * <p>A typical way to use this class is to add extra items to the * {@code CompositeData} in addition to the ones that are declared in the * {@code CompositeType} supplied by the MXBean framework.  To do this, * you must create another {@code CompositeType} that has all the same items, * plus your extra items.</p> * * <p>For example, suppose you have a class {@code Measure} that consists of * a String called {@code units} and a {@code value} that is either a * {@code long} or a {@code double}.  It might look like this:</p> * * <pre> * public class Measure implements CompositeDataView { *     private String units; *     private Number value; // a Long or a Double * *     public Measure(String units, Number value) { *         this.units = units; *         this.value = value; *     } * *     public static Measure from(CompositeData cd) { *         return new Measure((String) cd.get("units"), *                            (Number) cd.get("value")); *     } * *     public String getUnits() { *         return units; *     } * *     // Can't be called getValue(), because Number is not a valid type *     // in an MXBean, so the implied "value" property would be rejected. *     public Number _getValue() { *         return value; *     } * *     public CompositeData toCompositeData(CompositeType ct) { *         try { *             {@code List<String> itemNames = new ArrayList<String>(ct.keySet());} *             {@code List<String> itemDescriptions = new ArrayList<String>();} *             {@code List<OpenType<?>> itemTypes = new ArrayList<OpenType<?>>();} *             for (String item : itemNames) { *                 itemDescriptions.add(ct.getDescription(item)); *                 itemTypes.add(ct.getType(item)); *             } *             itemNames.add("value"); *             itemDescriptions.add("long or double value of the measure"); *             itemTypes.add((value instanceof Long) ? SimpleType.LONG : *                           SimpleType.DOUBLE); *             CompositeType xct = *                 new CompositeType(ct.getTypeName(), *                                   ct.getDescription(), *                                   itemNames.toArray(new String[0]), *                                   itemDescriptions.toArray(new String[0]), *                                   itemTypes.toArray(new OpenType&lt;?&gt;[0])); *             CompositeData cd = *                 new CompositeDataSupport(xct, *                                          new String[] {"units", "value"}, *                                          new Object[] {units, value}); *             assert ct.isValue(cd);  // check we've done it right *             return cd; *         } catch (Exception e) { *             throw new RuntimeException(e); *         } *     } * } * </pre> * * <p>The {@code CompositeType} that will appear in the {@code openType} field * of the {@link javax.management.Descriptor Descriptor} for an attribute or * operation of this type will show only the {@code units} item, but the actual * {@code CompositeData} that is generated will have both {@code units} and * {@code value}.</p> * * @see javax.management.MXBean * * @since 1.6 */public interface CompositeDataView {    /**     * <p>Return a {@code CompositeData} corresponding to the values in     * this object.  The returned value should usually be an instance of     * {@link CompositeDataSupport}, or a class that serializes as a     * {@code CompositeDataSupport} via a {@code writeReplace} method.     * Otherwise, a remote client that receives the object might not be     * able to reconstruct it.     *     * @param ct The expected {@code CompositeType} of the returned     * value.  If the returned value is {@code cd}, then     * {@code cd.getCompositeType().equals(ct)} should be true.     * Typically this will be because {@code cd} is a     * {@link CompositeDataSupport} constructed with {@code ct} as its     * {@code CompositeType}.     *     * @return the {@code CompositeData}.     */    public CompositeData toCompositeData(CompositeType ct);}