1 /* 2 * Copyright (c) 1999, 2014, 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.sampled; 27 28 import java.util.EventObject; 29 30 /** 31 * The {@code LineEvent} class encapsulates information that a line sends its 32 * listeners whenever the line opens, closes, starts, or stops. Each of these 33 * four state changes is represented by a corresponding type of event. A 34 * listener receives the event as a parameter to its 35 * {@link LineListener#update update} method. By querying the event, the 36 * listener can learn the type of event, the line responsible for the event, and 37 * how much data the line had processed when the event occurred. 38 * <p> 39 * Although this class implements Serializable, attempts to serialize a 40 * {@code LineEvent} object will fail. 41 * 42 * @author Kara Kytle 43 * @see Line 44 * @see LineListener#update 45 * @since 1.3 46 * 47 * @serial exclude 48 */ 49 public class LineEvent extends EventObject { 50 51 /** 52 * Use serialVersionUID from JDK 1.3 for interoperability. 53 */ 54 private static final long serialVersionUID = -1274246333383880410L; 55 56 /** 57 * The kind of line event ({@code OPEN}, {@code CLOSE}, {@code START}, or 58 * {@code STOP}). 59 * 60 * @see #getType 61 * @serial 62 */ 63 private final Type type; 64 65 /** 66 * The media position when the event occurred, expressed in sample frames. 67 * Note that this field is only relevant to certain events generated by data 68 * lines, such as {@code START} and {@code STOP}. For events generated by 69 * lines that do not count sample frames, and for any other events for which 70 * this value is not known, the position value should be 71 * {@link AudioSystem#NOT_SPECIFIED}. 72 * 73 * @see #getFramePosition 74 * @serial 75 */ 76 private final long position; 77 78 /** 79 * Constructs a new event of the specified type, originating from the 80 * specified line. 81 * 82 * @param line the source of this event 83 * @param type the event type ({@code OPEN}, {@code CLOSE}, {@code START}, 84 * or {@code STOP}) 85 * @param position the number of sample frames that the line had already 86 * processed when the event occurred, or 87 * {@link AudioSystem#NOT_SPECIFIED} 88 * @throws IllegalArgumentException if {@code line} is {@code null} 89 */ 90 public LineEvent(Line line, Type type, long position) { 91 92 super(line); 93 this.type = type; 94 this.position = position; 95 } 96 97 /** 98 * Obtains the audio line that is the source of this event. 99 * 100 * @return the line responsible for this event 101 */ 102 public final Line getLine() { 103 104 return (Line)getSource(); 105 } 106 107 /** 108 * Obtains the event's type. 109 * 110 * @return this event's type ({@link Type#OPEN}, {@link Type#CLOSE}, 111 * {@link Type#START}, or {@link Type#STOP}) 112 */ 113 public final Type getType() { 114 115 return type; 116 } 117 118 /** 119 * Obtains the position in the line's audio data when the event occurred, 120 * expressed in sample frames. For example, if a source line had already 121 * played back 14 sample frames at the time it was paused, the pause event 122 * would report the line's position as 14. The next frame to be processed 123 * would be frame number 14 using zero-based numbering, or 15 using 124 * one-based numbering. 125 * <p> 126 * Note that this field is relevant only to certain events generated by data 127 * lines, such as {@code START} and {@code STOP}. For events generated by 128 * lines that do not count sample frames, and for any other events for which 129 * this value is not known, the position value should be 130 * {@link AudioSystem#NOT_SPECIFIED}. 131 * 132 * @return the line's position as a sample frame number 133 */ 134 /* 135 * $$kk: 04.20.99: note to myself: should make sure our implementation is 136 * consistent with this. 137 * which is a reasonable definition.... 138 */ 139 public final long getFramePosition() { 140 141 return position; 142 } 143 144 /** 145 * Obtains a string representation of the event. The contents of the string 146 * may vary between implementations of Java Sound. 147 * 148 * @return a string describing the event 149 */ 150 @Override 151 public String toString() { 152 String sType = ""; 153 if (type != null) sType = type.toString()+" "; 154 String sLine; 155 if (getLine() == null) { 156 sLine = "null"; 157 } else { 158 sLine = getLine().toString(); 159 } 160 return new String(sType + "event from line " + sLine); 161 } 162 163 /** 164 * The LineEvent.Type inner class identifies what kind of event occurred on 165 * a line. Static instances are provided for the common types (OPEN, CLOSE, 166 * START, and STOP). 167 * 168 * @see LineEvent#getType() 169 */ 170 public static class Type { 171 172 /** 173 * Type name. 174 */ 175 private final String name; 176 177 /** 178 * Constructs a new event type. 179 * 180 * @param name name of the type 181 */ 182 protected Type(String name) { 183 this.name = name; 184 } 185 186 //$$fb 2002-11-26: fix for 4695001: SPEC: description of equals() method contains typo 187 188 /** 189 * Indicates whether the specified object is equal to this event type, 190 * returning {@code true} if the objects are identical. 191 * 192 * @param obj the reference object with which to compare 193 * @return {@code true} if this event type is the same as the 194 * {@code obj} argument; {@code false} otherwise 195 */ 196 @Override 197 public final boolean equals(Object obj) { 198 return super.equals(obj); 199 } 200 201 /** 202 * Returns a hash code value for this event type. 203 * 204 * @return a hash code value for this event type 205 */ 206 @Override 207 public final int hashCode() { 208 return super.hashCode(); 209 } 210 211 /** 212 * Returns the type name as the string representation. 213 * 214 * @return the type name as the string representation 215 */ 216 @Override 217 public String toString() { 218 return name; 219 } 220 221 // LINE EVENT TYPE DEFINES 222 223 /** 224 * A type of event that is sent when a line opens, reserving system 225 * resources for itself. 226 * 227 * @see #CLOSE 228 * @see Line#open 229 */ 230 public static final Type OPEN = new Type("Open"); 231 232 /** 233 * A type of event that is sent when a line closes, freeing the system 234 * resources it had obtained when it was opened. 235 * 236 * @see #OPEN 237 * @see Line#close 238 */ 239 public static final Type CLOSE = new Type("Close"); 240 241 /** 242 * A type of event that is sent when a line begins to engage in active 243 * input or output of audio data in response to a 244 * {@link DataLine#start start} request. 245 * 246 * @see #STOP 247 * @see DataLine#start 248 */ 249 public static final Type START = new Type("Start"); 250 251 /** 252 * A type of event that is sent when a line ceases active input or 253 * output of audio data in response to a {@link DataLine#stop stop} 254 * request, or because the end of media has been reached. 255 * 256 * @see #START 257 * @see DataLine#stop 258 */ 259 public static final Type STOP = new Type("Stop"); 260 261 /** 262 * A type of event that is sent when a line ceases to engage in active 263 * input or output of audio data because the end of media has been 264 * reached. 265 */ 266 /* 267 * ISSUE: we may want to get rid of this. Is JavaSound responsible for 268 * reporting this?? 269 * 270 * [If it's decided to keep this API, the docs will need to be updated 271 * to include mention of EOM events elsewhere.] 272 */ 273 //public static final Type EOM = new Type("EOM"); 274 275 /** 276 * A type of event that is sent when a line begins to engage in active 277 * input or output of audio data. Examples of when this happens are when 278 * a source line begins or resumes writing data to its mixer, and when a 279 * target line begins or resumes reading data from its mixer. 280 * 281 * @see #STOP 282 * @see SourceDataLine#write 283 * @see TargetDataLine#read 284 * @see DataLine#start 285 */ 286 //public static final Type ACTIVE = new Type("ACTIVE"); 287 288 /** 289 * A type of event that is sent when a line ceases active input or 290 * output of audio data. 291 * 292 * @see #START 293 * @see DataLine#stop 294 */ 295 //public static final Type INACTIVE = new Type("INACTIVE"); 296 } 297 }