diff --git a/event-queue/README.md b/event-queue/README.md new file mode 100644 index 000000000..e69de29bb diff --git a/event-queue/etc/Bass-Drum-1.wav b/event-queue/etc/Bass-Drum-1.wav new file mode 100644 index 000000000..566181d94 Binary files /dev/null and b/event-queue/etc/Bass-Drum-1.wav differ diff --git a/event-queue/etc/Closed-Hi-Hat-1.wav b/event-queue/etc/Closed-Hi-Hat-1.wav new file mode 100644 index 000000000..2320db510 Binary files /dev/null and b/event-queue/etc/Closed-Hi-Hat-1.wav differ diff --git a/event-queue/pom.xml b/event-queue/pom.xml new file mode 100644 index 000000000..16ee381b3 --- /dev/null +++ b/event-queue/pom.xml @@ -0,0 +1,42 @@ + + + + 4.0.0 + + com.iluwatar + java-design-patterns + 1.16.0-SNAPSHOT + + event-queue + + + junit + junit + test + + + diff --git a/event-queue/src/main/java/com/iluwatar/event/queue/App.java b/event-queue/src/main/java/com/iluwatar/event/queue/App.java new file mode 100644 index 000000000..a84027ecb --- /dev/null +++ b/event-queue/src/main/java/com/iluwatar/event/queue/App.java @@ -0,0 +1,67 @@ +/** + * The MIT License + * Copyright (c) 2014-2016 Ilkka Seppälä + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +package com.iluwatar.event.queue; + +import java.io.BufferedReader; +import java.io.File; +import java.io.IOException; +import java.io.InputStreamReader; + +import javax.sound.sampled.AudioInputStream; +import javax.sound.sampled.AudioSystem; +import javax.sound.sampled.UnsupportedAudioFileException; + +/** + * Event or message queues provide an asynchronous communications protocol, meaning that the sender + * and receiver of the message do not need to interact with the message queue at the same time. + * Events or messages placed onto the queue are stored until the recipient retrieves them. Event + * or message queues have implicit or explicit limits on the size of data that may be transmitted + * in a single message and the number of messages that may remain outstanding on the queue. + * A queue stores a series of notifications or requests in first-in, first-out order. + * Sending a notification enqueues the request and returns. The request processor then processes + * items from the queue at a later time. + */ +public class App { + /** + * Program entry point. + * + * @param args command line args + * @throws IOException when there is a problem with the audio file loading + * @throws UnsupportedAudioFileException when the loaded audio file is unsupported + */ + public static void main(String[] args) throws UnsupportedAudioFileException, IOException { + Audio.playSound(getAudioStream("./etc/Bass-Drum-1.wav"), -10.0f); + Audio.playSound(getAudioStream("./etc/Closed-Hi-Hat-1.wav"), -8.0f); + + System.out.println("Press Enter key to stop the program..."); + BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); + br.read(); + Audio.stopService(); + } + + public static AudioInputStream getAudioStream(String filePath) + throws UnsupportedAudioFileException, IOException { + return AudioSystem.getAudioInputStream(new File(filePath).getAbsoluteFile()); + } +} diff --git a/event-queue/src/main/java/com/iluwatar/event/queue/Audio.java b/event-queue/src/main/java/com/iluwatar/event/queue/Audio.java new file mode 100644 index 000000000..a9f0c5a67 --- /dev/null +++ b/event-queue/src/main/java/com/iluwatar/event/queue/Audio.java @@ -0,0 +1,131 @@ +/** + * The MIT License + * Copyright (c) 2014-2016 Ilkka Seppälä + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +package com.iluwatar.event.queue; + +import java.io.IOException; + +import javax.sound.sampled.AudioInputStream; +import javax.sound.sampled.AudioSystem; +import javax.sound.sampled.Clip; +import javax.sound.sampled.LineUnavailableException; + +/** + * This class implements the Event Queue pattern. + * @author mkuprivecz + * + */ +public class Audio { + + private static final int MAX_PENDING = 16; + + private static int headIndex; + + private static int tailIndex; + + private static Thread updateThread = null; + + private static PlayMessage[] pendingAudio = new PlayMessage[MAX_PENDING]; + + public static boolean isServiceRunning() { + return updateThread.isAlive(); + } + + /** + * This method stops the Update Method's thread. + */ + public static void stopService() { + if (updateThread != null) { + updateThread.interrupt(); + } + } + + /** + * Starts the thread for the Update Method pattern if it was not started previously. + * Also when the thread is is ready initializes the indexes of the queue + */ + public static void init() { + if (updateThread == null) { + updateThread = new Thread(new Runnable() { + public void run() { + while (!Thread.currentThread().isInterrupted()) { + Audio.update(); + } + } + }); + } + if (!updateThread.isAlive()) { + updateThread.start(); + headIndex = 0; + tailIndex = 0; + } + } + + /** + * This method adds a new audio into the queue. + * @param stream is the AudioInputStream for the method + * @param volume is the level of the audio's volume + */ + public static void playSound(AudioInputStream stream, float volume) { + init(); + // Walk the pending requests. + for (int i = headIndex; i != tailIndex; i = (i + 1) % MAX_PENDING) { + if (pendingAudio[i].stream == stream) { + // Use the larger of the two volumes. + pendingAudio[i].volume = Math.max(volume, pendingAudio[i].volume); + + // Don't need to enqueue. + return; + } + } + pendingAudio[tailIndex] = new PlayMessage(); + pendingAudio[tailIndex].stream = stream; + pendingAudio[tailIndex].volume = volume; + tailIndex = (tailIndex + 1) % MAX_PENDING; + } + + /** + * This method uses the Update Method pattern. + * It takes the audio from the queue and plays it + */ + public static void update() { + // If there are no pending requests, do nothing. + if (headIndex == tailIndex) { + return; + } + Clip clip = null; + try { + clip = AudioSystem.getClip(); + clip.open(pendingAudio[headIndex].stream); + } catch (LineUnavailableException e) { + System.err.println("Error occoured while loading the audio: The line is unavailable"); + e.printStackTrace(); + } catch (IOException e) { + System.err.println("Input/Output error while loading the audio"); + e.printStackTrace(); + } + clip.start(); + + headIndex++; + } +} diff --git a/event-queue/src/main/java/com/iluwatar/event/queue/PlayMessage.java b/event-queue/src/main/java/com/iluwatar/event/queue/PlayMessage.java new file mode 100644 index 000000000..5d151e8d5 --- /dev/null +++ b/event-queue/src/main/java/com/iluwatar/event/queue/PlayMessage.java @@ -0,0 +1,36 @@ +/** + * The MIT License + * Copyright (c) 2014-2016 Ilkka Seppälä + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +package com.iluwatar.event.queue; + +import javax.sound.sampled.AudioInputStream; + +/** + * The Event Queue's queue will store the instances of this class. + * @author mkuprivecz + * + */ +public class PlayMessage { + AudioInputStream stream; + float volume; +} diff --git a/pom.xml b/pom.xml index 4b9740857..bca17e99a 100644 --- a/pom.xml +++ b/pom.xml @@ -133,6 +133,7 @@ promise page-object event-asynchronous + event-queue queue-load-leveling object-mother converter