1 /* 2 * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 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). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 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 }