/*
 * @(#)MBeanNotificationInfo.java	1.32 04/02/10
 * 
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package javax.management;

import java.util.Arrays;

/**
 * <p>The <CODE>MBeanNotificationInfo</CODE> class is used to describe the 
 * characteristics of the different notification instances 
 * emitted by an MBean, for a given Java class of notification. 
 * If an MBean emits notifications that can be instances of different Java classes,
 * then the metadata for that MBean should provide an <CODE>MBeanNotificationInfo</CODE>
 * object for each of these notification Java classes.</p>
 *
 * <p>Instances of this class are immutable.  Subclasses may be
 * mutable but this is not recommended.</p>
 *
 * <p>This class extends <CODE>javax.management.MBeanFeatureInfo</CODE> 
 * and thus provides <CODE>name</CODE> and <CODE>description</CODE> fields.
 * The <CODE>name</CODE> field should be the fully qualified Java class name of
 * the notification objects described by this class.</p>
 *
 * <p>The <CODE>getNotifTypes</CODE> method returns an array of
 * strings containing the notification types that the MBean may
 * emit. The notification type is a dot-notation string which
 * describes what the emitted notification is about, not the Java
 * class of the notification.  A single generic notification class can
 * be used to send notifications of several types.  All of these types
 * are returned in the string array result of the
 * <CODE>getNotifTypes</CODE> method.
 *
 * @since 1.5
 */
public class MBeanNotificationInfo extends MBeanFeatureInfo implements Cloneable, java.io.Serializable  { 
  
    /* Serial version */
    static final long serialVersionUID = -3888371564530107064L;

    private static final String[] NO_TYPES = new String[0];

    static final MBeanNotificationInfo[] NO_NOTIFICATIONS =
	new MBeanNotificationInfo[0];

    /**
     * @serial The different types of the notification.  
     */
    private final String[] types;
    
    /** @see MBeanInfo#immutable */
    private final transient boolean immutable;

    /**
     * Constructs an <CODE>MBeanNotificationInfo</CODE> object.
     *
     * @param notifTypes The array of strings (in dot notation)
     * containing the notification types that the MBean may emit.
     * This may be null with the same effect as a zero-length array.
     * @param name The fully qualified Java class name of the
     * described notifications.
     * @param description A human readable description of the data.
     */
    public MBeanNotificationInfo(String[] notifTypes,
				 String name,
				 String description)
	    throws IllegalArgumentException {
	super(name, description);
	

	/* We do not validate the notifTypes, since the spec just says
	   they are dot-separated, not that they must look like Java
	   classes.  E.g. the spec doesn't forbid "sun.prob.25" as a
	   notifType, though it doesn't explicitly allow it
	   either.  */

	if (notifTypes == null)
	    notifTypes = NO_TYPES;
	this.types = notifTypes;
	this.immutable =
	    MBeanInfo.isImmutableClass(this.getClass(),
				       MBeanNotificationInfo.class);
    }


    /**
     * Returns a shallow clone of this instance. 
     * The clone is obtained by simply calling <tt>super.clone()</tt>, 
     * thus calling the default native shallow cloning mechanism 
     * implemented by <tt>Object.clone()</tt>.
     * No deeper cloning of any internal field is made.
     */
     public Object clone () {
	 try {
	     return  super.clone() ;
	 } catch (CloneNotSupportedException e) {
	     // should not happen as this class is cloneable
	     return null;
	 }
     }

    
    /**
     * Returns the array of strings (in dot notation) containing the
     * notification types that the MBean may emit.
     *
     * @return the array of strings.  Changing the returned array has no
     * effect on this MBeanNotificationInfo.
     */
    public String[] getNotifTypes() {
	if (types.length == 0)
            return NO_TYPES;
        else
            return (String[]) types.clone();
    }

    private String[] fastGetNotifTypes() {
	if (immutable)
	    return types;
	else
	    return getNotifTypes();
    }

    /**
     * Compare this MBeanAttributeInfo to another.
     *
     * @param o the object to compare to.
     *
     * @return true iff <code>o</code> is an MBeanNotificationInfo
     * such that its {@link #getName()}, {@link #getDescription()},
     * and {@link #getNotifTypes()} values are equal (not necessarily
     * identical) to those of this MBeanNotificationInfo.  Two
     * notification type arrays are equal if their corresponding
     * elements are equal.  They are not equal if they have the same
     * elements but in a different order.
     */
    public boolean equals(Object o) {
	if (o == this)
	    return true;
	if (!(o instanceof MBeanNotificationInfo))
	    return false;
	MBeanNotificationInfo p = (MBeanNotificationInfo) o;
	return (p.getName().equals(getName()) &&
		p.getDescription().equals(getDescription()) &&
		Arrays.equals(p.fastGetNotifTypes(), fastGetNotifTypes()));
    }

    public int hashCode() {
	int hash = getName().hashCode();
	for (int i = 0; i < types.length; i++)
	    hash ^= types[i].hashCode();
	return hash;
    }
}