Add internet radio source cache

This helps us avoid loading and parsing the external playlists each time
we try to load an internet radio.

airsonic-main/src/main/java/org/airsonic/player/ajax/PlayQueueService.java

@@ -449,6 +449,7 @@ public class PlayQueueService {
     }
 
     private PlayQueueInfo doPlayInternetRadio(HttpServletRequest request, Player player, InternetRadio radio) throws Exception {
+        internetRadioService.clearInternetRadioSourceCache(radio.getId());
         player.getPlayQueue().clear();
         player.getPlayQueue().setRandomSearchCriteria(null);
         player.getPlayQueue().setInternetRadio(radio);
@@ -742,35 +743,31 @@ public class PlayQueueService {
         final String radioName = radio.getName();
 
         List<PlayQueueInfo.Entry> entries = new ArrayList<>();
-        for (String streamUrl : internetRadioService.getStreamUrls(radio)) {
-            // Fake stream title using the URL
-            String streamTitle = streamUrl;
-            String streamAlbum = radioName;
-            String streamGenre = "Internet Radio";
-            // Fake entry id so that the source can be selected
+        for (InternetRadioSource streamSource: internetRadioService.getInternetRadioSources(radio)) {
+            // Fake entry id so that the source can be selected in the UI
             Integer streamId = -(1+entries.size());
             Integer streamTrackNumber = entries.size();
-            Integer streamYear = 0;
+            String streamUrl = streamSource.getStreamUrl();
             entries.add(new PlayQueueInfo.Entry(
                     streamId,          // Entry id
                     streamTrackNumber, // Track number
-                    streamTitle,       // Use URL as stream title
-                    "",
-                    streamAlbum,       // Album name
-                    streamGenre,
-                    streamYear,
-                    "",
-                    0,
-                    "",
-                    "",
-                    "",
-                    "",
-                    false,
-                    radioHomepageUrl,  // Album URL
+                    streamUrl,         // Track title (use radio stream URL for now)
+                    "",                // Track artist
+                    radioName,         // Album name (use radio name)
+                    "Internet Radio",  // Genre
+                    0,                 // Year
+                    "",                // Bit rate
+                    0,                 // Duration
+                    "",                // Duration (as string)
+                    "",                // Format
+                    "",                // Content Type
+                    "",                // File size
+                    false,             // Starred
+                    radioHomepageUrl,  // Album URL (use radio home page URL)
                     streamUrl,         // Stream URL
                     streamUrl,         // Remote stream URL
-                    null,
-                    null
+                    null,              // Cover art URL
+                    null               // Remote cover art URL
             ));
         }
 

airsonic-main/src/main/java/org/airsonic/player/domain/InternetRadioSource.java

@@ -0,0 +1,11 @@
+package org.airsonic.player.domain;
+
+public class InternetRadioSource {
+    private String streamUrl;
+
+    public InternetRadioSource(String streamUrl) {
+        this.streamUrl = streamUrl;
+    }
+
+    public String getStreamUrl() { return streamUrl; }
+}

airsonic-main/src/main/java/org/airsonic/player/service/InternetRadioService.java

@@ -2,21 +2,41 @@ package org.airsonic.player.service;
 
 import chameleon.playlist.*;
 import org.airsonic.player.domain.InternetRadio;
+import org.airsonic.player.domain.InternetRadioSource;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.stereotype.Service;
 
 import java.net.URL;
-import java.util.ArrayList;
-import java.util.List;
+import java.util.*;
 
 @Service
 public class InternetRadioService {
 
     private static final Logger LOG = LoggerFactory.getLogger(InternetRadioService.class);
 
-    public List<String> getStreamUrls(InternetRadio radio) throws Exception {
+    private Map<Integer, List<InternetRadioSource>> cachedSources;
 
+    public InternetRadioService() {
+        this.cachedSources = new HashMap<>();
+    }
+
+    public void clearInternetRadioSourceCache() {
+        cachedSources.clear();
+    }
+
+    public List<InternetRadioSource> getInternetRadioSources(InternetRadio radio) throws Exception {
+        List<InternetRadioSource> sources;
+        if (cachedSources.containsKey(radio.getId())) {
+            sources = cachedSources.get(radio.getId());
+        } else {
+            sources = retrieveInternetRadioSources(radio);
+            cachedSources.put(radio.getId(), sources);
+        }
+        return sources;
+    }
+
+    private List<InternetRadioSource> retrieveInternetRadioSources(InternetRadio radio) throws Exception {
         // Retrieve radio playlist and parse it
         URL playlistUrl = new URL(radio.getStreamUrl());
         SpecificPlaylist inputPlaylist = null;
@@ -33,7 +53,7 @@ public class InternetRadioService {
         }
 
         // Retrieve stream URLs
-        List<String> entries = new ArrayList<>();
+        List<InternetRadioSource> entries = new ArrayList<>();
         inputPlaylist.toPlaylist().acceptDown(new PlaylistVisitor() {
             @Override
             public void beginVisitPlaylist(Playlist playlist) throws Exception {
@@ -69,7 +89,9 @@ public class InternetRadioService {
             public void beginVisitMedia(Media media) throws Exception {
                 String streamUrl = media.getSource().getURI().toString();
                 LOG.info("Got source media at {}...", streamUrl);
-                entries.add(streamUrl);
+                entries.add(new InternetRadioSource(
+                    streamUrl
+                ));
             }
 
             @Override