| /* |
| * Copyright (c) 2007, 2008, 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 com.sun.jmx.mbeanserver; |
| |
| import java.io.InvalidObjectException; |
| import java.lang.reflect.Type; |
| import javax.management.openmbean.OpenDataException; |
| import javax.management.openmbean.OpenType; |
| |
| /** |
| * <p>A custom mapping between Java types and Open types for use in MXBeans. |
| * To define such a mapping, subclass this class and define at least the |
| * {@link #fromOpenValue fromOpenValue} and {@link #toOpenValue toOpenValue} |
| * methods, and optionally the {@link #checkReconstructible} method. |
| * Then either use an {@link MXBeanMappingClass} annotation on your custom |
| * Java types, or include this MXBeanMapping in an |
| * {@link MXBeanMappingFactory}.</p> |
| * |
| * <p>For example, suppose we have a class {@code MyLinkedList}, which looks |
| * like this:</p> |
| * |
| * <pre> |
| * public class MyLinkedList { |
| * public MyLinkedList(String name, MyLinkedList next) {...} |
| * public String getName() {...} |
| * public MyLinkedList getNext() {...} |
| * } |
| * </pre> |
| * |
| * <p>This is not a valid type for MXBeans, because it contains a |
| * self-referential property "next" defined by the {@code getNext()} |
| * method. MXBeans do not support recursive types. So we would like |
| * to specify a mapping for {@code MyLinkedList} explicitly. When an |
| * MXBean interface contains {@code MyLinkedList}, that will be mapped |
| * into a {@code String[]}, which is a valid Open Type.</p> |
| * |
| * <p>To define this mapping, we first subclass {@code MXBeanMapping}:</p> |
| * |
| * <pre> |
| * public class MyLinkedListMapping extends MXBeanMapping { |
| * public MyLinkedListMapping(Type type) throws OpenDataException { |
| * super(MyLinkedList.class, ArrayType.getArrayType(SimpleType.STRING)); |
| * if (type != MyLinkedList.class) |
| * throw new OpenDataException("Mapping only valid for MyLinkedList"); |
| * } |
| * |
| * {@literal @Override} |
| * public Object fromOpenValue(Object openValue) throws InvalidObjectException { |
| * String[] array = (String[]) openValue; |
| * MyLinkedList list = null; |
| * for (int i = array.length - 1; i >= 0; i--) |
| * list = new MyLinkedList(array[i], list); |
| * return list; |
| * } |
| * |
| * {@literal @Override} |
| * public Object toOpenValue(Object javaValue) throws OpenDataException { |
| * ArrayList<String> array = new ArrayList<String>(); |
| * for (MyLinkedList list = (MyLinkedList) javaValue; list != null; |
| * list = list.getNext()) |
| * array.add(list.getName()); |
| * return array.toArray(new String[0]); |
| * } |
| * } |
| * </pre> |
| * |
| * <p>The call to the superclass constructor specifies what the |
| * original Java type is ({@code MyLinkedList.class}) and what Open |
| * Type it is mapped to ({@code |
| * ArrayType.getArrayType(SimpleType.STRING)}). The {@code |
| * fromOpenValue} method says how we go from the Open Type ({@code |
| * String[]}) to the Java type ({@code MyLinkedList}), and the {@code |
| * toOpenValue} method says how we go from the Java type to the Open |
| * Type.</p> |
| * |
| * <p>With this mapping defined, we can annotate the {@code MyLinkedList} |
| * class appropriately:</p> |
| * |
| * <pre> |
| * {@literal @MXBeanMappingClass}(MyLinkedListMapping.class) |
| * public class MyLinkedList {...} |
| * </pre> |
| * |
| * <p>Now we can use {@code MyLinkedList} in an MXBean interface and it |
| * will work.</p> |
| * |
| * <p>If we are unable to modify the {@code MyLinkedList} class, |
| * we can define an {@link MXBeanMappingFactory}. See the documentation |
| * of that class for further details.</p> |
| * |
| * @see <a href="../MXBean.html#custom">MXBean specification, section |
| * "Custom MXBean type mappings"</a> |
| */ |
| public abstract class MXBeanMapping { |
| private final Type javaType; |
| private final OpenType<?> openType; |
| private final Class<?> openClass; |
| |
| /** |
| * <p>Construct a mapping between the given Java type and the given |
| * Open Type.</p> |
| * |
| * @param javaType the Java type (for example, {@code MyLinkedList}). |
| * @param openType the Open Type (for example, {@code |
| * ArrayType.getArrayType(SimpleType.STRING)}) |
| * |
| * @throws NullPointerException if either argument is null. |
| */ |
| protected MXBeanMapping(Type javaType, OpenType<?> openType) { |
| if (javaType == null || openType == null) |
| throw new NullPointerException("Null argument"); |
| this.javaType = javaType; |
| this.openType = openType; |
| this.openClass = makeOpenClass(javaType, openType); |
| } |
| |
| /** |
| * <p>The Java type that was supplied to the constructor.</p> |
| * @return the Java type that was supplied to the constructor. |
| */ |
| public final Type getJavaType() { |
| return javaType; |
| } |
| |
| /** |
| * <p>The Open Type that was supplied to the constructor.</p> |
| * @return the Open Type that was supplied to the constructor. |
| */ |
| public final OpenType<?> getOpenType() { |
| return openType; |
| } |
| |
| /** |
| * <p>The Java class that corresponds to instances of the |
| * {@linkplain #getOpenType() Open Type} for this mapping.</p> |
| * @return the Java class that corresponds to instances of the |
| * Open Type for this mapping. |
| * @see OpenType#getClassName |
| */ |
| public final Class<?> getOpenClass() { |
| return openClass; |
| } |
| |
| private static Class<?> makeOpenClass(Type javaType, OpenType<?> openType) { |
| if (javaType instanceof Class<?> && ((Class<?>) javaType).isPrimitive()) |
| return (Class<?>) javaType; |
| try { |
| String className = openType.getClassName(); |
| return Class.forName(className, false, null); |
| } catch (ClassNotFoundException e) { |
| throw new RuntimeException(e); // should not happen |
| } |
| } |
| |
| /** |
| * <p>Convert an instance of the Open Type into the Java type. |
| * @param openValue the value to be converted. |
| * @return the converted value. |
| * @throws InvalidObjectException if the value cannot be converted. |
| */ |
| public abstract Object fromOpenValue(Object openValue) |
| throws InvalidObjectException; |
| |
| /** |
| * <p>Convert an instance of the Java type into the Open Type. |
| * @param javaValue the value to be converted. |
| * @return the converted value. |
| * @throws OpenDataException if the value cannot be converted. |
| */ |
| public abstract Object toOpenValue(Object javaValue) |
| throws OpenDataException; |
| |
| |
| /** |
| * <p>Throw an appropriate InvalidObjectException if we will not |
| * be able to convert back from the open data to the original Java |
| * object. The {@link #fromOpenValue fromOpenValue} throws an |
| * exception if a given open data value cannot be converted. This |
| * method throws an exception if <em>no</em> open data values can |
| * be converted. The default implementation of this method never |
| * throws an exception. Subclasses can override it as |
| * appropriate.</p> |
| * @throws InvalidObjectException if {@code fromOpenValue} will throw |
| * an exception no matter what its argument is. |
| */ |
| public void checkReconstructible() throws InvalidObjectException {} |
| } |