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/*
 * Copyright (c) 2013, 2015, 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 jdk.dio.gpio;

import jdk.dio.DeviceEvent;

/**
 * The {@code PortEvent} class encapsulates GPIO port value changes. When/if value change events for
 * the same GPIO port are coalesced the value retained is that of the last occurrence.
 *
 * @see GPIOPort
 * @see PortListener
 * @since 1.0
 */
@apimarker.API("device-io_1.1_gpio")
public class PortEvent extends DeviceEvent {

    /**
     * The new GPIO port's value.
     */
    private int value;

    /**
     * Creates a new {@link PortEvent} with the specified value and time-stamped with the current
     * time.
     *
     * @param port
     *            the source GPIO port.
     * @param value
     *            the new value.
     * @throws NullPointerException
     *             if {@code port} is {@code null}.
     */
    public PortEvent(GPIOPort port, int value) {
        this(port, value, System.currentTimeMillis(), 0);
    }

    /**
     * Creates a new {@link PortEvent} with the specified value and timestamp.
     *
     * @param port
     *            the source GPIO port.
     * @param value
     *            the new value.
     * @param timeStamp
     *            the timestamp (in milliseconds).
     * @param timeStampMicros
     *            the additional microseconds to the timestamp.
     * @throws NullPointerException
     *             if {@code port} is {@code null}.
     * @throws IllegalArgumentException
     *             if {@code timeStamp} is negative or
     *             {@code timeStampMicros} is not in the range {@code [0 - 999]}.
     */
    public PortEvent(GPIOPort port, int value, long timeStamp, int timeStampMicros) {
        // checks for null
        port.isOpen();
        if (0 > timeStamp || 0 > timeStampMicros || timeStampMicros > 999) {
            throw new IllegalArgumentException();
        }
        this.device = port;
        this.value = value;
        this.timeStamp = timeStamp;
        this.timeStampMicros = timeStampMicros;
        this.count = 1;
    }

    /**
     * Returns the new GPIO port's value.
     *
     * @return the new GPIO port's value.
     */
    public int getValue() {
        return value;
    }
}