/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 *
 * ident        "%Z%%M% %I%     %E% SMI"
 */
package org.opensolaris.os.dtrace;

import java.io.*;
import java.util.EventObject;

/**
 * An event used to pass probe data generated by a DTrace {@link
 * Consumer} to interested listeners.
 *
 * @see ConsumerListener#dataReceived(DataEvent e)
 *
 * @author Tom Erickson
 */
public class DataEvent extends EventObject {
    static final long serialVersionUID = 3068774547474769821L;

    /** @serial */
    private ProbeData probeData;

    /**
     * Creates a {@link ConsumerListener#dataReceived(DataEvent e)
     * dataReceived()} event that conveys data generated by DTrace from
     * a single probe firing.
     *
     * @throws NullPointerException if the given probe data is {@code
     * null}
     */
    public
    DataEvent(Object source, ProbeData generatedData)
    {
        super(source);
        probeData = generatedData;
        validate();
    }

    private final void
    validate()
    {
        if (probeData == null) {
            throw new NullPointerException("probe data is null");
        }
    }

    /**
     * Gets the data generated by DTrace from a single probe firing.
     *
     * @return non-null probe data generated by DTrace from a single
     * probe firing
     */
    public ProbeData
    getProbeData()
    {
        return probeData;
    }

    private void
    readObject(ObjectInputStream s)
            throws IOException, ClassNotFoundException
    {
        s.defaultReadObject();
        // check invariants
        try {
            validate();
        } catch (Exception e) {
            InvalidObjectException x = new InvalidObjectException(
                    e.getMessage());
            x.initCause(e);
            throw x;
        }
    }

    /**
     * Gets a string representation of this event useful for logging and
     * not intended for display.  The exact details of the
     * representation are unspecified and subject to change, but the
     * following format may be regarded as typical:
     * <pre><code>
     * class-name[property1 = value1, property2 = value2]
     * </code></pre>
     */
    public String
    toString()
    {
        StringBuilder buf = new StringBuilder();
        buf.append(DataEvent.class.getName());
        buf.append("[source = ");
        buf.append(getSource());
        buf.append(", probeData = ");
        buf.append(probeData);
        buf.append(']');
        return buf.toString();
    }
}