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 * Copyright (c) 1999, 2018, 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

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 */

package javax.sound.sampled;

import java.util.EventObject;

/**

 * The {@code LineEvent} class encapsulates information that a line sends its

 * listeners whenever the line opens, closes, starts, or stops. Each of these

 * four state changes is represented by a corresponding type of event. A

 * listener receives the event as a parameter to its

 * {@link LineListener#update update} method. By querying the event, the

 * listener can learn the type of event, the line responsible for the event, and

 * how much data the line had processed when the event occurred.

 * <p>

 * Although this class implements Serializable, attempts to serialize a

 * {@code LineEvent} object will fail.

 *

 * @author Kara Kytle

 * @see Line

 * @see LineListener#update

 * @since 1.3

 *

 * @serial exclude

 */

public class LineEvent extends EventObject {

    /**

     * Use serialVersionUID from JDK 1.3 for interoperability.

     */

    private static final long serialVersionUID = -1274246333383880410L;

    /**

     * The kind of line event ({@code OPEN}, {@code CLOSE}, {@code START}, or

     * {@code STOP}).

     *

     * @see #getType

     * @serial

     */

    private final Type type;

    /**

     * The media position when the event occurred, expressed in sample frames.

     * Note that this field is only relevant to certain events generated by data

     * lines, such as {@code START} and {@code STOP}. For events generated by

     * lines that do not count sample frames, and for any other events for which

     * this value is not known, the position value should be

     * {@link AudioSystem#NOT_SPECIFIED}.

     *

     * @see #getFramePosition

     * @serial

     */

    private final long position;

    /**

     * Constructs a new event of the specified type, originating from the

     * specified line.

     *

     * @param  line the source of this event

     * @param  type the event type ({@code OPEN}, {@code CLOSE}, {@code START},

     *         or {@code STOP})

     * @param  position the number of sample frames that the line had already

     *         processed when the event occurred, or

     *         {@link AudioSystem#NOT_SPECIFIED}

     * @throws IllegalArgumentException if {@code line} is {@code null}

     */

    public LineEvent(Line line, Type type, long position) {

        super(line);

        this.type = type;

        this.position = position;

    }

    /**

     * Obtains the audio line that is the source of this event.

     *

     * @return the line responsible for this event

     */

    public final Line getLine() {

        return (Line)getSource();

    }

    /**

     * Obtains the event's type.

     *

     * @return this event's type ({@link Type#OPEN}, {@link Type#CLOSE},

     *         {@link Type#START}, or {@link Type#STOP})

     */

    public final Type getType() {

        return type;

    }

    /**

     * Obtains the position in the line's audio data when the event occurred,

     * expressed in sample frames. For example, if a source line had already

     * played back 14 sample frames at the time it was paused, the pause event

     * would report the line's position as 14. The next frame to be processed

     * would be frame number 14 using zero-based numbering, or 15 using

     * one-based numbering.

     * <p>

     * Note that this field is relevant only to certain events generated by data

     * lines, such as {@code START} and {@code STOP}. For events generated by

     * lines that do not count sample frames, and for any other events for which

     * this value is not known, the position value should be

     * {@link AudioSystem#NOT_SPECIFIED}.

     *

     * @return the line's position as a sample frame number

     */

    /*

     * $$kk: 04.20.99: note to myself: should make sure our implementation is

     * consistent with this.

     * which is a reasonable definition....

     */

    public final long getFramePosition() {

        return position;

    }

    /**

     * Obtains a string representation of the event. The contents of the string

     * may vary between implementations of Java Sound.

     *

     * @return a string describing the event

     */

    @Override

    public String toString() {

        String sType = "";

        if (type != null) sType = type.toString()+" ";

        String sLine;

        if (getLine() == null) {

            sLine = "null";

        } else {

            sLine = getLine().toString();

        }

        return new String(sType + "event from line " + sLine);

    }

    /**

     * The LineEvent.Type inner class identifies what kind of event occurred on

     * a line. Static instances are provided for the common types (OPEN, CLOSE,

     * START, and STOP).

     *

     * @see LineEvent#getType()

     */

    public static class Type {

        /**

         * Type name.

         */

        private final String name;

        /**

         * Constructs a new event type.

         *

         * @param  name name of the type

         */

        protected Type(String name) {

            this.name = name;

        }

        //$$fb 2002-11-26: fix for 4695001: SPEC: description of equals() method contains typo

        /**

         * Indicates whether the specified object is equal to this event type,

         * returning {@code true} if the objects are the same.

         *

         * @param  obj the reference object with which to compare

         * @return {@code true} if the specified object is equal to this event

         *         type; {@code false} otherwise

         */

        @Override

        public final boolean equals(Object obj) {

            return super.equals(obj);

        }

        /**

         * Returns a hash code value for this event type.

         *

         * @return a hash code value for this event type

         */

        @Override

        public final int hashCode() {

            return super.hashCode();

        }

        /**

         * Returns the type name as the string representation.

         *

         * @return the type name as the string representation

         */

        @Override

        public String toString() {

            return name;

        }

        // LINE EVENT TYPE DEFINES

        /**

         * A type of event that is sent when a line opens, reserving system

         * resources for itself.

         *

         * @see #CLOSE

         * @see Line#open

         */

        public static final Type OPEN = new Type("Open");

        /**

         * A type of event that is sent when a line closes, freeing the system

         * resources it had obtained when it was opened.

         *

         * @see #OPEN

         * @see Line#close

         */

        public static final Type CLOSE = new Type("Close");

        /**

         * A type of event that is sent when a line begins to engage in active

         * input or output of audio data in response to a

         * {@link DataLine#start start} request.

         *

         * @see #STOP

         * @see DataLine#start

         */

        public static final Type START = new Type("Start");

        /**

         * A type of event that is sent when a line ceases active input or

         * output of audio data in response to a {@link DataLine#stop stop}

         * request, or because the end of media has been reached.

         *

         * @see #START

         * @see DataLine#stop

         */

        public static final Type STOP = new Type("Stop");

        /**

         * A type of event that is sent when a line ceases to engage in active

         * input or output of audio data because the end of media has been

         * reached.

         */

        /*

         * ISSUE: we may want to get rid of this. Is JavaSound responsible for

         * reporting this??

         *

         * [If it's decided to keep this API, the docs will need to be updated

         * to include mention of EOM events elsewhere.]

         */

        //public static final Type EOM  = new Type("EOM");

        /**

         * A type of event that is sent when a line begins to engage in active

         * input or output of audio data. Examples of when this happens are when

         * a source line begins or resumes writing data to its mixer, and when a

         * target line begins or resumes reading data from its mixer.

         *

         * @see #STOP

         * @see SourceDataLine#write

         * @see TargetDataLine#read

         * @see DataLine#start

         */

        //public static final Type ACTIVE       = new Type("ACTIVE");

        /**

         * A type of event that is sent when a line ceases active input or

         * output of audio data.

         *

         * @see #START

         * @see DataLine#stop

         */

        //public static final Type INACTIVE     = new Type("INACTIVE");

    }

}