| /* |
| * Copyright (c) 1999, 2019, 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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| * questions. |
| */ |
| |
| package javax.sound.sampled; |
| |
| /** |
| * The {@code Line} interface represents a mono or multi-channel audio feed. A |
| * line is an element of the digital audio "pipeline," such as a mixer, an input |
| * or output port, or a data path into or out of a mixer. |
| * <p> |
| * A line can have controls, such as gain, pan, and reverb. The controls |
| * themselves are instances of classes that extend the base {@link Control} |
| * class. The {@code Line} interface provides two accessor methods for obtaining |
| * the line's controls: {@link #getControls getControls} returns the entire set, |
| * and {@link #getControl getControl} returns a single control of specified |
| * type. |
| * <p> |
| * Lines exist in various states at different times. When a line opens, it |
| * reserves system resources for itself, and when it closes, these resources are |
| * freed for other objects or applications. The {@link #isOpen()} method lets |
| * you discover whether a line is open or closed. An open line need not be |
| * processing data, however. Such processing is typically initiated by |
| * subinterface methods such as |
| * {@link SourceDataLine#write SourceDataLine.write} and |
| * {@link TargetDataLine#read TargetDataLine.read}. |
| * <p> |
| * You can register an object to receive notifications whenever the line's state |
| * changes. The object must implement the {@link LineListener} interface, which |
| * consists of the single method {@link LineListener#update update}. This method |
| * will be invoked when a line opens and closes (and, if it's a {@link DataLine} |
| * , when it starts and stops). |
| * <p> |
| * An object can be registered to listen to multiple lines. The event it |
| * receives in its {@code update} method will specify which line created the |
| * event, what type of event it was ({@code OPEN}, {@code CLOSE}, {@code START}, |
| * or {@code STOP}), and how many sample frames the line had processed at the |
| * time the event occurred. |
| * <p> |
| * Certain line operations, such as open and close, can generate security |
| * exceptions if invoked by unprivileged code when the line is a shared audio |
| * resource. |
| * |
| * @author Kara Kytle |
| * @see LineEvent |
| * @since 1.3 |
| */ |
| public interface Line extends AutoCloseable { |
| |
| /** |
| * Obtains the {@code Line.Info} object describing this line. |
| * |
| * @return description of the line |
| */ |
| Line.Info getLineInfo(); |
| |
| /** |
| * Opens the line, indicating that it should acquire any required system |
| * resources and become operational. If this operation succeeds, the line is |
| * marked as open, and an {@code OPEN} event is dispatched to the line's |
| * listeners. |
| * <p> |
| * Note that some lines, once closed, cannot be reopened. Attempts to reopen |
| * such a line will always result in an {@code LineUnavailableException}. |
| * <p> |
| * Some types of lines have configurable properties that may affect resource |
| * allocation. For example, a {@code DataLine} must be opened with a |
| * particular format and buffer size. Such lines should provide a mechanism |
| * for configuring these properties, such as an additional {@code open} |
| * method or methods which allow an application to specify the desired |
| * settings. |
| * <p> |
| * This method takes no arguments, and opens the line with the current |
| * settings. For {@link SourceDataLine} and {@link TargetDataLine} objects, |
| * this means that the line is opened with default settings. For a |
| * {@link Clip}, however, the buffer size is determined when data is loaded. |
| * Since this method does not allow the application to specify any data to |
| * load, an {@code IllegalArgumentException} is thrown. Therefore, you |
| * should instead use one of the {@code open} methods provided in the |
| * {@code Clip} interface to load data into the {@code Clip}. |
| * <p> |
| * For {@code DataLine}'s, if the {@code DataLine.Info} object which was |
| * used to retrieve the line, specifies at least one fully qualified audio |
| * format, the last one will be used as the default format. |
| * |
| * @throws IllegalArgumentException if this method is called on a Clip |
| * instance |
| * @throws LineUnavailableException if the line cannot be opened due to |
| * resource restrictions |
| * @throws SecurityException if the line cannot be opened due to security |
| * restrictions |
| * @see #close |
| * @see #isOpen |
| * @see LineEvent |
| * @see DataLine |
| * @see Clip#open(AudioFormat, byte[], int, int) |
| * @see Clip#open(AudioInputStream) |
| */ |
| void open() throws LineUnavailableException; |
| |
| /** |
| * Closes the line, indicating that any system resources in use by the line |
| * can be released. If this operation succeeds, the line is marked closed |
| * and a {@code CLOSE} event is dispatched to the line's listeners. |
| * |
| * @throws SecurityException if the line cannot be closed due to security |
| * restrictions |
| * @see #open |
| * @see #isOpen |
| * @see LineEvent |
| */ |
| @Override |
| void close(); |
| |
| /** |
| * Indicates whether the line is open, meaning that it has reserved system |
| * resources and is operational, although it might not currently be playing |
| * or capturing sound. |
| * |
| * @return {@code true} if the line is open, otherwise {@code false} |
| * @see #open() |
| * @see #close() |
| */ |
| boolean isOpen(); |
| |
| /** |
| * Obtains the set of controls associated with this line. Some controls may |
| * only be available when the line is open. If there are no controls, this |
| * method returns an array of length 0. |
| * |
| * @return the array of controls |
| * @see #getControl |
| */ |
| Control[] getControls(); |
| |
| /** |
| * Indicates whether the line supports a control of the specified type. Some |
| * controls may only be available when the line is open. |
| * |
| * @param control the type of the control for which support is queried |
| * @return {@code true} if at least one control of the specified type is |
| * supported, otherwise {@code false} |
| */ |
| boolean isControlSupported(Control.Type control); |
| |
| /** |
| * Obtains a control of the specified type, if there is any. Some controls |
| * may only be available when the line is open. |
| * |
| * @param control the type of the requested control |
| * @return a control of the specified type |
| * @throws IllegalArgumentException if a control of the specified type is |
| * not supported |
| * @see #getControls |
| * @see #isControlSupported(Control.Type control) |
| */ |
| Control getControl(Control.Type control); |
| |
| /** |
| * Adds a listener to this line. Whenever the line's status changes, the |
| * listener's {@code update()} method is called with a {@code LineEvent} |
| * object that describes the change. |
| * |
| * @param listener the object to add as a listener to this line |
| * @see #removeLineListener |
| * @see LineListener#update |
| * @see LineEvent |
| */ |
| void addLineListener(LineListener listener); |
| |
| /** |
| * Removes the specified listener from this line's list of listeners. |
| * |
| * @param listener listener to remove |
| * @see #addLineListener |
| */ |
| void removeLineListener(LineListener listener); |
| |
| /** |
| * A {@code Line.Info} object contains information about a line. The only |
| * information provided by {@code Line.Info} itself is the Java class of the |
| * line. A subclass of {@code Line.Info} adds other kinds of information |
| * about the line. This additional information depends on which {@code Line} |
| * subinterface is implemented by the kind of line that the |
| * {@code Line.Info} subclass describes. |
| * <p> |
| * A {@code Line.Info} can be retrieved using various methods of the |
| * {@code Line}, {@code Mixer}, and {@code AudioSystem} interfaces. Other |
| * such methods let you pass a {@code Line.Info} as an argument, to learn |
| * whether lines matching the specified configuration are available and to |
| * obtain them. |
| * |
| * @author Kara Kytle |
| * @see Line#getLineInfo() |
| * @see Mixer#getSourceLineInfo() |
| * @see Mixer#getTargetLineInfo() |
| * @see Mixer#getLine(Line.Info) |
| * @see Mixer#getSourceLineInfo(Line.Info) |
| * @see Mixer#getTargetLineInfo(Line.Info) |
| * @see Mixer#isLineSupported(Line.Info) |
| * @see AudioSystem#getLine(Line.Info) |
| * @see AudioSystem#getSourceLineInfo(Line.Info) |
| * @see AudioSystem#getTargetLineInfo(Line.Info) |
| * @see AudioSystem#isLineSupported(Line.Info) |
| * @since 1.3 |
| */ |
| class Info { |
| |
| /** |
| * The class of the line described by the info object. |
| */ |
| private final Class<?> lineClass; |
| |
| /** |
| * Constructs an info object that describes a line of the specified |
| * class. This constructor is typically used by an application to |
| * describe a desired line. |
| * |
| * @param lineClass the class of the line that the new |
| * {@code Line.Info} object describes |
| */ |
| public Info(Class<?> lineClass) { |
| |
| if (lineClass == null) { |
| this.lineClass = Line.class; |
| } else { |
| this.lineClass = lineClass; |
| } |
| } |
| |
| /** |
| * Obtains the class of the line that this {@code Line.Info} object |
| * describes. |
| * |
| * @return the described line's class |
| */ |
| public Class<?> getLineClass() { |
| return lineClass; |
| } |
| |
| /** |
| * Indicates whether the specified info object matches this one. To |
| * match, the specified object must be identical to or a special case of |
| * this one. The specified info object must be either an instance of the |
| * same class as this one, or an instance of a sub-type of this one. In |
| * addition, the attributes of the specified object must be compatible |
| * with the capabilities of this one. Specifically, the routing |
| * configuration for the specified info object must be compatible with |
| * that of this one. Subclasses may add other criteria to determine |
| * whether the two objects match. |
| * |
| * @param info the info object which is being compared to this one |
| * @return {@code true} if the specified object matches this one, |
| * {@code false} otherwise |
| */ |
| public boolean matches(Info info) { |
| |
| // $$kk: 08.30.99: is this backwards? |
| // dataLine.matches(targetDataLine) == true: targetDataLine is always dataLine |
| // targetDataLine.matches(dataLine) == false |
| // so if i want to make sure i get a targetDataLine, i need: |
| // targetDataLine.matches(prospective_match) == true |
| // => prospective_match may be other things as well, but it is at least a targetDataLine |
| // targetDataLine defines the requirements which prospective_match must meet. |
| |
| |
| // "if this Class object represents a declared class, this method returns |
| // true if the specified Object argument is an instance of the represented |
| // class (or of any of its subclasses)" |
| // GainControlClass.isInstance(MyGainObj) => true |
| // GainControlClass.isInstance(MySpecialGainInterfaceObj) => true |
| |
| // this_class.isInstance(that_object) => that object can by cast to this class |
| // => that_object's class may be a subtype of this_class |
| // => that may be more specific (subtype) of this |
| |
| // "If this Class object represents an interface, this method returns true |
| // if the class or any superclass of the specified Object argument implements |
| // this interface" |
| // GainControlClass.isInstance(MyGainObj) => true |
| // GainControlClass.isInstance(GenericControlObj) => may be false |
| // => that may be more specific |
| |
| if (! (this.getClass().isInstance(info)) ) { |
| return false; |
| } |
| |
| // this.isAssignableFrom(that) => this is same or super to that |
| // => this is at least as general as that |
| // => that may be subtype of this |
| |
| if (! (getLineClass().isAssignableFrom(info.getLineClass())) ) { |
| return false; |
| } |
| |
| return true; |
| } |
| |
| /** |
| * Obtains a textual description of the line info. |
| * |
| * @return a string description |
| */ |
| @Override |
| public String toString() { |
| final String str = getLineClass().toString(); |
| if (getLineClass().getPackage() == Line.class.getPackage()) { |
| return str.replace("javax.sound.sampled.", ""); |
| } |
| return str; |
| } |
| } |
| } |
