1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
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  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
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  23  * questions.
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  25 
  26 package javax.sound.midi;
  27 
  28 import java.util.List;
  29 
  30  /**
  31  * <code>MidiDevice</code> is the base interface for all MIDI devices.
  32  * Common devices include synthesizers, sequencers, MIDI input ports, and MIDI
  33  * output ports.
  34  *
  35  * <p>A <code>MidiDevice</code> can be a transmitter or a receiver of
  36  * MIDI events, or both. Therefore, it can provide {@link Transmitter}
  37  * or {@link Receiver} instances (or both). Typically, MIDI IN ports
  38  * provide transmitters, MIDI OUT ports and synthesizers provide
  39  * receivers. A Sequencer typically provides transmitters for playback
  40  * and receivers for recording.
  41  *
  42  * <p>A <code>MidiDevice</code> can be opened and closed explicitly as
  43  * well as implicitly. Explicit opening is accomplished by calling
  44  * {@link #open}, explicit closing is done by calling {@link
  45  * #close} on the <code>MidiDevice</code> instance.
  46  * If an application opens a <code>MidiDevice</code>
  47  * explicitly, it has to close it explicitly to free system resources
  48  * and enable the application to exit cleanly. Implicit opening is
  49  * done by calling {@link javax.sound.midi.MidiSystem#getReceiver
  50  * MidiSystem.getReceiver} and {@link
  51  * javax.sound.midi.MidiSystem#getTransmitter
  52  * MidiSystem.getTransmitter}. The <code>MidiDevice</code> used by
  53  * <code>MidiSystem.getReceiver</code> and
  54  * <code>MidiSystem.getTransmitter</code> is implementation-dependant
  55  * unless the properties <code>javax.sound.midi.Receiver</code>
  56  * and <code>javax.sound.midi.Transmitter</code> are used (see the
  57  * description of properties to select default providers in
  58  * {@link javax.sound.midi.MidiSystem}). A <code>MidiDevice</code>
  59  * that was opened implicitly, is closed implicitly by closing the
  60  * <code>Receiver</code> or <code>Transmitter</code> that resulted in
  61  * opening it. If more than one implicitly opening
  62  * <code>Receiver</code> or <code>Transmitter</code> were obtained by
  63  * the application, the decive is closed after the last
  64  * <code>Receiver</code> or <code>Transmitter</code> has been
  65  * closed. On the other hand, calling <code>getReceiver</code> or
  66  * <code>getTransmitter</code> on the device instance directly does
  67  * not open the device implicitly. Closing these
  68  * <code>Transmitter</code>s and <code>Receiver</code>s does not close
  69  * the device implicitly. To use a device with <code>Receiver</code>s
  70  * or <code>Transmitter</code>s obtained this way, the device has to
  71  * be opened and closed explicitly.
  72  *
  73  * <p>If implicit and explicit opening and closing are mixed on the
  74  * same <code>MidiDevice</code> instance, the following rules apply:
  75  *
  76  * <ul>
  77  * <li>After an explicit open (either before or after implicit
  78  * opens), the device will not be closed by implicit closing. The only
  79  * way to close an explicitly opened device is an explicit close.</li>
  80  *
  81  * <li>An explicit close always closes the device, even if it also has
  82  * been opened implicitly. A subsequent implicit close has no further
  83  * effect.</li>
  84  * </ul>
  85  *
  86  * To detect if a MidiDevice represents a hardware MIDI port, the
  87  * following programming technique can be used:
  88  *
  89  * <pre>
  90  * MidiDevice device = ...;
  91  * if ( ! (device instanceof Sequencer) && ! (device instanceof Synthesizer)) {
  92  *   // we're now sure that device represents a MIDI port
  93  *   // ...
  94  * }
  95  * </pre>
  96  *
  97  * <p>
  98  * A <code>MidiDevice</code> includes a <code>{@link MidiDevice.Info}</code> object
  99  * to provide manufacturer information and so on.
 100  *
 101  * @see Synthesizer
 102  * @see Sequencer
 103  * @see Receiver
 104  * @see Transmitter
 105  *
 106  * @author Kara Kytle
 107  * @author Florian Bomers
 108  */
 109 
 110 public interface MidiDevice extends AutoCloseable {
 111 
 112 
 113     /**
 114      * Obtains information about the device, including its Java class and
 115      * <code>Strings</code> containing its name, vendor, and description.
 116      *
 117      * @return device info
 118      */
 119     public Info getDeviceInfo();
 120 
 121 
 122     /**
 123      * Opens the device, indicating that it should now acquire any
 124      * system resources it requires and become operational.
 125      *
 126      * <p>An application opening a device explicitly with this call
 127      * has to close the device by calling {@link #close}. This is
 128      * necessary to release system resources and allow applications to
 129      * exit cleanly.
 130      *
 131      * <p>
 132      * Note that some devices, once closed, cannot be reopened.  Attempts
 133      * to reopen such a device will always result in a MidiUnavailableException.
 134      *
 135      * @throws MidiUnavailableException thrown if the device cannot be
 136      * opened due to resource restrictions.
 137      * @throws SecurityException thrown if the device cannot be
 138      * opened due to security restrictions.
 139      *
 140      * @see #close
 141      * @see #isOpen
 142      */
 143     public void open() throws MidiUnavailableException;
 144 
 145 
 146     /**
 147      * Closes the device, indicating that the device should now release
 148      * any system resources it is using.
 149      *
 150      * <p>All <code>Receiver</code> and <code>Transmitter</code> instances
 151      * open from this device are closed. This includes instances retrieved
 152      * via <code>MidiSystem</code>.
 153      *
 154      * @see #open
 155      * @see #isOpen
 156      */
 157     public void close();
 158 
 159 
 160     /**
 161      * Reports whether the device is open.
 162      *
 163      * @return <code>true</code> if the device is open, otherwise
 164      * <code>false</code>
 165      * @see #open
 166      * @see #close
 167      */
 168     public boolean isOpen();
 169 
 170 
 171     /**
 172      * Obtains the current time-stamp of the device, in microseconds.
 173      * If a device supports time-stamps, it should start counting at
 174      * 0 when the device is opened and continue incrementing its
 175      * time-stamp in microseconds until the device is closed.
 176      * If it does not support time-stamps, it should always return
 177      * -1.
 178      * @return the current time-stamp of the device in microseconds,
 179      * or -1 if time-stamping is not supported by the device.
 180      */
 181     public long getMicrosecondPosition();
 182 
 183 
 184     /**
 185      * Obtains the maximum number of MIDI IN connections available on this
 186      * MIDI device for receiving MIDI data.
 187      * @return maximum number of MIDI IN connections,
 188      * or -1 if an unlimited number of connections is available.
 189      */
 190     public int getMaxReceivers();
 191 
 192 
 193     /**
 194      * Obtains the maximum number of MIDI OUT connections available on this
 195      * MIDI device for transmitting MIDI data.
 196      * @return maximum number of MIDI OUT connections,
 197      * or -1 if an unlimited number of connections is available.
 198      */
 199     public int getMaxTransmitters();
 200 
 201 
 202     /**
 203      * Obtains a MIDI IN receiver through which the MIDI device may receive
 204      * MIDI data.  The returned receiver must be closed when the application
 205      * has finished using it.
 206      *
 207      * <p>Usually the returned receiver implements
 208      * the {@code MidiDeviceReceiver} interface.
 209      *
 210      * <p>Obtaining a <code>Receiver</code> with this method does not
 211      * open the device. To be able to use the device, it has to be
 212      * opened explicitly by calling {@link #open}. Also, closing the
 213      * <code>Receiver</code> does not close the device. It has to be
 214      * closed explicitly by calling {@link #close}.
 215      *
 216      * @return a receiver for the device.
 217      * @throws MidiUnavailableException thrown if a receiver is not available
 218      * due to resource restrictions
 219      * @see Receiver#close()
 220      */
 221     public Receiver getReceiver() throws MidiUnavailableException;
 222 
 223 
 224     /**
 225      * Returns all currently active, non-closed receivers
 226      * connected with this MidiDevice.
 227      * A receiver can be removed
 228      * from the device by closing it.
 229      *
 230      * <p>Usually the returned receivers implement
 231      * the {@code MidiDeviceReceiver} interface.
 232      *
 233      * @return an unmodifiable list of the open receivers
 234      * @since 1.5
 235      */
 236     List<Receiver> getReceivers();
 237 
 238 
 239     /**
 240      * Obtains a MIDI OUT connection from which the MIDI device will transmit
 241      * MIDI data  The returned transmitter must be closed when the application
 242      * has finished using it.
 243      *
 244      * <p>Usually the returned transmitter implements
 245      * the {@code MidiDeviceTransmitter} interface.
 246      *
 247      * <p>Obtaining a <code>Transmitter</code> with this method does not
 248      * open the device. To be able to use the device, it has to be
 249      * opened explicitly by calling {@link #open}. Also, closing the
 250      * <code>Transmitter</code> does not close the device. It has to be
 251      * closed explicitly by calling {@link #close}.
 252      *
 253      * @return a MIDI OUT transmitter for the device.
 254      * @throws MidiUnavailableException thrown if a transmitter is not available
 255      * due to resource restrictions
 256      * @see Transmitter#close()
 257      */
 258     public Transmitter getTransmitter() throws MidiUnavailableException;
 259 
 260 
 261     /**
 262      * Returns all currently active, non-closed transmitters
 263      * connected with this MidiDevice.
 264      * A transmitter can be removed
 265      * from the device by closing it.
 266      *
 267      * <p>Usually the returned transmitters implement
 268      * the {@code MidiDeviceTransmitter} interface.
 269      *
 270      * @return an unmodifiable list of the open transmitters
 271      * @since 1.5
 272      */
 273     List<Transmitter> getTransmitters();
 274 
 275 
 276 
 277     /**
 278      * A <code>MidiDevice.Info</code> object contains assorted
 279      * data about a <code>{@link MidiDevice}</code>, including its
 280      * name, the company who created it, and descriptive text.
 281      *
 282      * @see MidiDevice#getDeviceInfo
 283      */
 284     public static class Info {
 285 
 286         /**
 287          * The device's name.
 288          */
 289         private String name;
 290 
 291         /**
 292          * The name of the company who provides the device.
 293          */
 294         private String vendor;
 295 
 296         /**
 297          * A description of the device.
 298          */
 299         private String description;
 300 
 301         /**
 302          * Device version.
 303          */
 304         private String version;
 305 
 306 
 307         /**
 308          * Constructs a device info object.
 309          *
 310          * @param name the name of the device
 311          * @param vendor the name of the company who provides the device
 312          * @param description a description of the device
 313          * @param version version information for the device
 314          */
 315         protected Info(String name, String vendor, String description, String version) {
 316 
 317             this.name = name;
 318             this.vendor = vendor;
 319             this.description = description;
 320             this.version = version;
 321         }
 322 
 323 
 324         /**
 325          * Reports whether two objects are equal.
 326          * Returns <code>true</code> if the objects are identical.
 327          * @param obj the reference object with which to compare this
 328          * object
 329          * @return <code>true</code> if this object is the same as the
 330          * <code>obj</code> argument; <code>false</code> otherwise
 331          */
 332         public final boolean equals(Object obj) {
 333             return super.equals(obj);
 334         }
 335 
 336 
 337         /**
 338          * Finalizes the hashcode method.
 339          */
 340         public final int hashCode() {
 341             return super.hashCode();
 342         }
 343 
 344 
 345         /**
 346          * Obtains the name of the device.
 347          *
 348          * @return a string containing the device's name
 349          */
 350         public final String getName() {
 351             return name;
 352         }
 353 
 354 
 355         /**
 356          * Obtains the name of the company who supplies the device.
 357          * @return device the vendor's name
 358          */
 359         public final String getVendor() {
 360             return vendor;
 361         }
 362 
 363 
 364         /**
 365          * Obtains the description of the device.
 366          * @return a description of the device
 367          */
 368         public final String getDescription() {
 369             return description;
 370         }
 371 
 372 
 373         /**
 374          * Obtains the version of the device.
 375          * @return textual version information for the device.
 376          */
 377         public final String getVersion() {
 378             return version;
 379         }
 380 
 381 
 382         /**
 383          * Provides a string representation of the device information.
 384 
 385          * @return a description of the info object
 386          */
 387         public final String toString() {
 388             return name;
 389         }
 390     } // class Info
 391 
 392 
 393 }