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	/*
	* Copyright (c) 1999, 2013, 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;

	import java.io.IOException;
	import java.io.ObjectInputStream;
	import java.io.ObjectOutputStream;
	import java.io.Serializable;
	import java.io.StreamCorruptedException;
	import java.util.Objects;

	/**
	* <p>Provides general information for an MBean descriptor object.
	* The feature described can be an attribute, an operation, a
	* parameter, or a notification. Instances of this class are
	* immutable. Subclasses may be mutable but this is not
	* recommended.</p>
	*
	* @since 1.5
	*/
	public class MBeanFeatureInfo implements Serializable, DescriptorRead {


	/* Serial version */
	static final long serialVersionUID = 3952882688968447265L;

	/**
	* The name of the feature. It is recommended that subclasses call
	* {@link #getName} rather than reading this field, and that they
	* not change it.
	*
	* @serial The name of the feature.
	*/
	protected String name;

	/**
	* The human-readable description of the feature. It is
	* recommended that subclasses call {@link #getDescription} rather
	* than reading this field, and that they not change it.
	*
	* @serial The human-readable description of the feature.
	*/
	protected String description;

	/**
	* @serial The Descriptor for this MBeanFeatureInfo. This field
	* can be null, which is equivalent to an empty Descriptor.
	*/
	private transient Descriptor descriptor;


	/**
	* Constructs an <CODE>MBeanFeatureInfo</CODE> object. This
	* constructor is equivalent to {@code MBeanFeatureInfo(name,
	* description, (Descriptor) null}.
	*
	* @param name The name of the feature.
	* @param description A human readable description of the feature.
	*/
	public MBeanFeatureInfo(String name, String description) {
	this(name, description, null);
	}

	/**
	* Constructs an <CODE>MBeanFeatureInfo</CODE> object.
	*
	* @param name The name of the feature.
	* @param description A human readable description of the feature.
	* @param descriptor The descriptor for the feature. This may be null
	* which is equivalent to an empty descriptor.
	*
	* @since 1.6
	*/
	public MBeanFeatureInfo(String name, String description,
	Descriptor descriptor) {
	this.name = name;
	this.description = description;
	this.descriptor = descriptor;
	}

	/**
	* Returns the name of the feature.
	*
	* @return the name of the feature.
	*/
	public String getName() {
	return name;
	}

	/**
	* Returns the human-readable description of the feature.
	*
	* @return the human-readable description of the feature.
	*/
	public String getDescription() {
	return description;
	}

	/**
	* Returns the descriptor for the feature. Changing the returned value
	* will have no affect on the original descriptor.
	*
	* @return a descriptor that is either immutable or a copy of the original.
	*
	* @since 1.6
	*/
	public Descriptor getDescriptor() {
	return (Descriptor) ImmutableDescriptor.nonNullDescriptor(descriptor).clone();
	}

	/**
	* Compare this MBeanFeatureInfo to another.
	*
	* @param o the object to compare to.
	*
	* @return true if and only if <code>o</code> is an MBeanFeatureInfo such
	* that its {@link #getName()}, {@link #getDescription()}, and
	* {@link #getDescriptor()}
	* values are equal (not necessarily identical) to those of this
	* MBeanFeatureInfo.
	*/
	public boolean equals(Object o) {
	if (o == this)
	return true;
	if (!(o instanceof MBeanFeatureInfo))
	return false;
	MBeanFeatureInfo p = (MBeanFeatureInfo) o;
	return (Objects.equals(p.getName(), getName()) &&
	Objects.equals(p.getDescription(), getDescription()) &&
	Objects.equals(p.getDescriptor(), getDescriptor()));
	}

	public int hashCode() {
	return getName().hashCode() ^ getDescription().hashCode() ^
	getDescriptor().hashCode();
	}

	/**
	* Serializes an {@link MBeanFeatureInfo} to an {@link ObjectOutputStream}.
	* @serialData
	* For compatibility reasons, an object of this class is serialized as follows.
	* <p>
	* The method {@link ObjectOutputStream#defaultWriteObject defaultWriteObject()}
	* is called first to serialize the object except the field {@code descriptor}
	* which is declared as transient. The field {@code descriptor} is serialized
	* as follows:
	* <ul>
	* <li>If {@code descriptor} is an instance of the class
	* {@link ImmutableDescriptor}, the method {@link ObjectOutputStream#write
	* write(int val)} is called to write a byte with the value {@code 1},
	* then the method {@link ObjectOutputStream#writeObject writeObject(Object obj)}
	* is called twice to serialize the field names and the field values of the
	* {@code descriptor}, respectively as a {@code String[]} and an
	* {@code Object[]};</li>
	* <li>Otherwise, the method {@link ObjectOutputStream#write write(int val)}
	* is called to write a byte with the value {@code 0}, then the method
	* {@link ObjectOutputStream#writeObject writeObject(Object obj)} is called
	* to serialize directly the field {@code descriptor}.
	* </ul>
	*
	* @since 1.6
	*/
	private void writeObject(ObjectOutputStream out) throws IOException {
	out.defaultWriteObject();

	if (descriptor != null &&
	descriptor.getClass() == ImmutableDescriptor.class) {

	out.write(1);

	final String[] names = descriptor.getFieldNames();

	out.writeObject(names);
	out.writeObject(descriptor.getFieldValues(names));
	} else {
	out.write(0);

	out.writeObject(descriptor);
	}
	}

	/**
	* Deserializes an {@link MBeanFeatureInfo} from an {@link ObjectInputStream}.
	* @serialData
	* For compatibility reasons, an object of this class is deserialized as follows.
	* <p>
	* The method {@link ObjectInputStream#defaultReadObject defaultReadObject()}
	* is called first to deserialize the object except the field
	* {@code descriptor}, which is not serialized in the default way. Then the method
	* {@link ObjectInputStream#read read()} is called to read a byte, the field
	* {@code descriptor} is deserialized according to the value of the byte value:
	* <ul>
	* <li>1. The method {@link ObjectInputStream#readObject readObject()}
	* is called twice to obtain the field names (a {@code String[]}) and
	* the field values (a {@code Object[]}) of the {@code descriptor}.
	* The two obtained values then are used to construct
	* an {@link ImmutableDescriptor} instance for the field
	* {@code descriptor};</li>
	* <li>0. The value for the field {@code descriptor} is obtained directly
	* by calling the method {@link ObjectInputStream#readObject readObject()}.
	* If the obtained value is null, the field {@code descriptor} is set to
	* {@link ImmutableDescriptor#EMPTY_DESCRIPTOR EMPTY_DESCRIPTOR};</li>
	* <li>-1. This means that there is no byte to read and that the object is from
	* an earlier version of the JMX API. The field {@code descriptor} is set
	* to {@link ImmutableDescriptor#EMPTY_DESCRIPTOR EMPTY_DESCRIPTOR}</li>
	* <li>Any other value. A {@link StreamCorruptedException} is thrown.</li>
	* </ul>
	*
	* @since 1.6
	*/
	private void readObject(ObjectInputStream in)
	throws IOException, ClassNotFoundException {

	in.defaultReadObject();

	switch (in.read()) {
	case 1:
	final String[] names = (String[])in.readObject();

	final Object[] values = (Object[]) in.readObject();
	descriptor = (names.length == 0) ?
	ImmutableDescriptor.EMPTY_DESCRIPTOR :
	new ImmutableDescriptor(names, values);

	break;
	case 0:
	descriptor = (Descriptor)in.readObject();

	if (descriptor == null) {
	descriptor = ImmutableDescriptor.EMPTY_DESCRIPTOR;
	}

	break;
	case -1: // from an earlier version of the JMX API
	descriptor = ImmutableDescriptor.EMPTY_DESCRIPTOR;

	break;
	default:
	throw new StreamCorruptedException("Got unexpected byte.");
	}
	}
	}

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