1 /*

     2  * Copyright 1999-2007 Sun Microsystems, Inc.  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.  Sun designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    22  * CA 95054 USA or visit www.sun.com if you need additional information or

    23  * have any questions.

    24  */

    25 

    26 package com.sun.media.sound;

    27 

    28 import java.util.Collections;

    29 import java.util.HashMap;

    30 import java.util.List;

    31 import java.util.Map;

    32 import java.util.Properties;

    33 

    34 import javax.sound.sampled.spi.AudioFileReader;

    35 import javax.sound.sampled.spi.AudioFileWriter;

    36 import javax.sound.sampled.spi.FormatConversionProvider;

    37 import javax.sound.sampled.spi.MixerProvider;

    38 

    39 import javax.sound.midi.spi.MidiFileReader;

    40 import javax.sound.midi.spi.MidiFileWriter;

    41 import javax.sound.midi.spi.SoundbankReader;

    42 import javax.sound.midi.spi.MidiDeviceProvider;

    43 

    44 

    45 /**

    46  * JDK13Services uses the Service class in JDK 1.3

    47  * to discover a list of service providers installed

    48  * in the system.

    49  *

    50  * This class is public because it is called from javax.sound.midi.MidiSystem

    51  * and javax.sound.sampled.AudioSystem. The alternative would be to make

    52  * JSSecurityManager public, which is considered worse.

    53  *

    54  * @author Matthias Pfisterer

    55  */

    56 public class JDK13Services {

    57 

    58     /** The default for the length of the period to hold the cache.

    59         This value is given in milliseconds. It is equivalent to

    60         1 minute.

    61     */

    62     private static final long DEFAULT_CACHING_PERIOD = 60000;

    63 

    64     /** Filename of the properties file for default provider properties.

    65         This file is searched in the subdirectory "lib" of the JRE directory

    66         (this behaviour is hardcoded).

    67     */

    68     private static final String PROPERTIES_FILENAME = "sound.properties";

    69 

    70     /** Cache for the providers.

    71         Class objects of the provider type (MixerProvider, MidiDeviceProvider

    72         ...) are used as keys. The values are instances of ProviderCache.

    73     */

    74     private static Map providersCacheMap = new HashMap();

    75 

    76 

    77     /** The length of the period to hold the cache.

    78         This value is given in milliseconds.

    79     */

    80     private static long cachingPeriod = DEFAULT_CACHING_PERIOD;

    81 

    82     /** Properties loaded from the properties file for default provider

    83         properties.

    84     */

    85     private static Properties properties;

    86 

    87 

    88     /** Private, no-args constructor to ensure against instantiation.

    89      */

    90     private JDK13Services() {

    91     }

    92 

    93 

    94     /** Set the period provider lists are cached.

    95         This method is only intended for testing.

    96      */

    97     public static void setCachingPeriod(int seconds) {

    98         cachingPeriod = seconds * 1000L;

    99     }

   100 

   101 

   102     /** Obtains a List containing installed instances of the

   103         providers for the requested service.

   104         The List of providers is cached for the period of time given by

   105         {@link #cachingPeriod cachingPeriod}. During this period, the same

   106         List instance is returned for the same type of provider. After this

   107         period, a new instance is constructed and returned. The returned

   108         List is immutable.

   109         @param serviceClass The type of providers requested. This should be one

   110         of AudioFileReader.class, AudioFileWriter.class,

   111         FormatConversionProvider.class, MixerProvider.class,

   112         MidiDeviceProvider.class, MidiFileReader.class, MidiFileWriter.class or

   113         SoundbankReader.class.

   114         @return A List of providers of the requested type. This List is

   115         immutable.

   116      */

   117     public static synchronized List getProviders(Class serviceClass) {

   118         ProviderCache cache = (ProviderCache) providersCacheMap.get(serviceClass);

   119         if (cache == null) {

   120             cache = new ProviderCache();

   121             providersCacheMap.put(serviceClass, cache);

   122         }

   123         if (cache.providers == null ||

   124             System.currentTimeMillis() > cache.lastUpdate + cachingPeriod) {

   125             cache.providers = Collections.unmodifiableList(JSSecurityManager.getProviders(serviceClass));

   126             cache.lastUpdate = System.currentTimeMillis();

   127         }

   128         return cache.providers;

   129     }

   130 

   131 

   132     /** Obtain the provider class name part of a default provider property.

   133         @param typeClass The type of the default provider property. This

   134         should be one of Receiver.class, Transmitter.class, Sequencer.class,

   135         Synthesizer.class, SourceDataLine.class, TargetDataLine.class,

   136         Clip.class or Port.class.

   137         @return The value of the provider class name part of the property

   138         (the part before the hash sign), if available. If the property is

   139         not set or the value has no provider class name part, null is returned.

   140      */

   141     public static synchronized String getDefaultProviderClassName(Class typeClass) {

   142         String value = null;

   143         String defaultProviderSpec = getDefaultProvider(typeClass);

   144         if (defaultProviderSpec != null) {

   145             int hashpos = defaultProviderSpec.indexOf('#');

   146             if (hashpos == 0) {

   147                 // instance name only; leave value as null

   148             } else if (hashpos > 0) {

   149                 value = defaultProviderSpec.substring(0, hashpos);

   150             } else {

   151                 value = defaultProviderSpec;

   152             }

   153         }

   154         return value;

   155     }

   156 

   157 

   158     /** Obtain the instance name part of a default provider property.

   159         @param typeClass The type of the default provider property. This

   160         should be one of Receiver.class, Transmitter.class, Sequencer.class,

   161         Synthesizer.class, SourceDataLine.class, TargetDataLine.class,

   162         Clip.class or Port.class.

   163         @return The value of the instance name part of the property (the

   164         part after the hash sign), if available. If the property is not set

   165         or the value has no instance name part, null is returned.

   166      */

   167     public static synchronized String getDefaultInstanceName(Class typeClass) {

   168         String value = null;

   169         String defaultProviderSpec = getDefaultProvider(typeClass);

   170         if (defaultProviderSpec != null) {

   171             int hashpos = defaultProviderSpec.indexOf('#');

   172             if (hashpos >= 0 && hashpos < defaultProviderSpec.length() - 1) {

   173                 value = defaultProviderSpec.substring(hashpos + 1);

   174             }

   175         }

   176         return value;

   177     }

   178 

   179 

   180     /** Obtain the value of a default provider property.

   181         @param typeClass The type of the default provider property. This

   182         should be one of Receiver.class, Transmitter.class, Sequencer.class,

   183         Synthesizer.class, SourceDataLine.class, TargetDataLine.class,

   184         Clip.class or Port.class.

   185         @return The complete value of the property, if available.

   186         If the property is not set, null is returned.

   187      */

   188     private static synchronized String getDefaultProvider(Class typeClass) {

   189         String value;

   190         String propertyName = typeClass.getName();

   191         value = JSSecurityManager.getProperty(propertyName);

   192         if (value == null) {

   193             value = getProperties().getProperty(propertyName);

   194         }

   195         if ("".equals(value)) {

   196             value = null;

   197         }

   198         return value;

   199     }

   200 

   201 

   202     /** Obtain a properties bundle containing property values from the

   203         properties file. If the properties file could not be loaded,

   204         the properties bundle is empty.

   205     */

   206     private static synchronized Properties getProperties() {

   207         if (properties == null) {

   208             properties = new Properties();

   209             JSSecurityManager.loadProperties(properties, PROPERTIES_FILENAME);

   210         }

   211         return properties;

   212     }

   213 

   214     // INNER CLASSES

   215 

   216     private static class ProviderCache {

   217         // System time of the last update in milliseconds.

   218         public long lastUpdate;

   219 

   220         // The providers.

   221         public List providers;

   222     }

   223 }