/*

 * 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

 * particular file as subject to the "Classpath" exception as provided

 *

 * 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.

 *

 */

package com.sun.jmx.mbeanserver;

import javax.management.openmbean.*;

import com.sun.jmx.mbeanserver.MXBeanMapping;

import com.sun.jmx.mbeanserver.DefaultMXBeanMappingFactory;

import java.lang.reflect.Type;

/**

 * <p>Defines how types are mapped for a given MXBean or set of MXBeans.

 * An {@code MXBeanMappingFactory} can be specified either through the

 * {@link MXBeanMappingFactoryClass} annotation, or through the

 * {@link javax.management.JMX.MBeanOptions JMX.MBeanOptions} argument to a

 * {@link javax.management.StandardMBean StandardMBean} constructor or MXBean

 * proxy.</p>

 *

 * <p>An {@code MXBeanMappingFactory} must return an {@code MXBeanMapping}

 * for any Java type that appears in the MXBeans that the factory is being

 * used for.  Usually it does that by handling any custom types, and

 * forwarding everything else to the {@linkplain #DEFAULT default mapping

 * factory}.</p>

 *

 * <p>Consider the {@code MyLinkedList} example from the {@link MXBeanMapping}

 * documentation.  If we are unable to change the {@code MyLinkedList} class

 * to add an {@link MXBeanMappingClass} annotation, we could achieve the same

 * effect by defining {@code MyLinkedListMappingFactory} as follows:</p>

 *

 * <pre>

 * public class MyLinkedListMappingFactory extends MXBeanMappingFactory {

 *     public MyLinkedListMappingFactory() {}

 *

 *     public MXBeanMapping mappingForType(Type t, MXBeanMappingFactory f)

 *     throws OpenDataException {

 *         if (t == MyLinkedList.class)

 *             return new MyLinkedListMapping(t);

 *         else

 *             return MXBeanMappingFactory.DEFAULT.mappingForType(t, f);

 *     }

 * }

 * </pre>

 *

 * <p>The mapping factory handles only the {@code MyLinkedList} class.

 * Every other type is forwarded to the default mapping factory.

 * This includes types such as {@code MyLinkedList[]} and

 * {@code List<MyLinkedList>}; the default mapping factory will recursively

 * invoke {@code MyLinkedListMappingFactory} to map the contained

 * {@code MyLinkedList} type.</p>

 *

 * <p>Once we have defined {@code MyLinkedListMappingFactory}, we can use

 * it in an MXBean interface like this:</p>

 *

 * <pre>

 * {@literal @MXBeanMappingFactoryClass}(MyLinkedListMappingFactory.class)

 * public interface SomethingMXBean {

 *     public MyLinkedList getSomething();

 * }

 * </pre>

 *

 * <p>Alternatively we can annotate the package that {@code SomethingMXBean}

 * appears in, or we can supply the factory to a {@link

 * javax.management.StandardMBean StandardMBean} constructor or MXBean

 * proxy.</p>

 *

 * @see <a href="../MXBean.html#custom">MXBean specification, section

 * "Custom MXBean type mappings"</a>

 */

public abstract class MXBeanMappingFactory {

    /**

     * <p>Construct an instance of this class.</p>

     */

    protected MXBeanMappingFactory() {}

    /**

     * <p>Mapping factory that applies the default rules for MXBean

     * mappings, as described in the <a

     * href="../MXBean.html#MXBean-spec">MXBean specification</a>.</p>

     */

    public static final MXBeanMappingFactory DEFAULT =

            new DefaultMXBeanMappingFactory();

    /**

     * <p>Return the mapping for the given Java type.  Typically, a

     * mapping factory will return mappings for types it handles, and

     * forward other types to another mapping factory, most often

     * the {@linkplain #DEFAULT default one}.</p>

     * @param t the Java type to be mapped.

     * @param f the original mapping factory that was consulted to do

     * the mapping.  A mapping factory should pass this parameter intact

     * if it forwards a type to another mapping factory.  In the example,

     * this is how {@code MyLinkedListMappingFactory} works for types

     * like {@code MyLinkedList[]} and {@code List<MyLinkedList>}.

     * @return the mapping for the given type.

     * @throws OpenDataException if this type cannot be mapped.  This

     * exception is appropriate if the factory is supposed to handle

     * all types of this sort (for example, all linked lists), but

     * cannot handle this particular type.

     */

    public abstract MXBeanMapping mappingForType(Type t, MXBeanMappingFactory f)

    throws OpenDataException;

}