[extensionservice] Add more null annotations (openhab#7348)

* [extensionservice] Add more null annotations * Use cachedNodes array again for easy atomic assignments * Prevent code from messing with cachedNodes Signed-off-by: Wouter Born <github@maindrain.net>
LoungeFlyZ · Jun 8, 2020 · eb5c603 · eb5c603
1 parent 55f247b
commit eb5c603
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Showing 7 changed files with 37 additions and 29 deletions.
diff --git a/...ketplace/src/main/java/org/openhab/extensionservice/marketplace/MarketplaceExtension.java b/...ketplace/src/main/java/org/openhab/extensionservice/marketplace/MarketplaceExtension.java
@@ -12,6 +12,8 @@
  */
 package org.openhab.extensionservice.marketplace;
 
+import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
 import org.eclipse.smarthome.core.extension.Extension;
 
 /**
@@ -20,6 +22,7 @@
  * @author Kai Kreuzer - Initial contribution and API
  *
  */
+@NonNullByDefault
 public class MarketplaceExtension extends Extension {
 
     // constants used to construct extension IDs
@@ -39,7 +42,8 @@ public class MarketplaceExtension extends Extension {
     private transient String packageFormat;
 
     public MarketplaceExtension(String id, String type, String label, String version, String link, boolean installed,
-            String description, String backgroundColor, String imageLink, String downloadUrl, String packageFormat) {
+            String description, @Nullable String backgroundColor, String imageLink, String downloadUrl,
+            String packageFormat) {
         super(id, type, label, version, link, installed, description, backgroundColor, imageLink);
         this.downloadUrl = downloadUrl;
         this.packageFormat = packageFormat;

diff --git a/...e/src/main/java/org/openhab/extensionservice/marketplace/MarketplaceExtensionHandler.java b/...e/src/main/java/org/openhab/extensionservice/marketplace/MarketplaceExtensionHandler.java
@@ -12,8 +12,7 @@
  */
 package org.openhab.extensionservice.marketplace;
 
-import org.openhab.extensionservice.marketplace.MarketplaceExtension;
-import org.openhab.extensionservice.marketplace.MarketplaceHandlerException;
+import org.eclipse.jdt.annotation.NonNullByDefault;
 
 /**
  * This interface can be implemented by services that want to register as handlers for specific marketplace extension
@@ -27,6 +26,7 @@
  * @author Kai Kreuzer - Initial contribution and API
  *
  */
+@NonNullByDefault
 public interface MarketplaceExtensionHandler {
 
     /**

diff --git a/...e/src/main/java/org/openhab/extensionservice/marketplace/MarketplaceHandlerException.java b/...e/src/main/java/org/openhab/extensionservice/marketplace/MarketplaceHandlerException.java
@@ -12,14 +12,15 @@
  */
 package org.openhab.extensionservice.marketplace;
 
-import org.openhab.extensionservice.marketplace.MarketplaceExtensionHandler;
+import org.eclipse.jdt.annotation.NonNullByDefault;
 
 /**
  * This is an exception that can be thrown by {@link MarketplaceExtensionHandler}s if some operation fails.
  *
  * @author Kai Kreuzer - Initial contribution and API
  *
  */
+@NonNullByDefault
 public class MarketplaceHandlerException extends Exception {
 
     private static final long serialVersionUID = -5652014141471618161L;

diff --git a/...ace/src/main/java/org/openhab/extensionservice/marketplace/internal/MarketplaceProxy.java b/...ace/src/main/java/org/openhab/extensionservice/marketplace/internal/MarketplaceProxy.java
@@ -22,9 +22,9 @@
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
 
+import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
 import org.eclipse.smarthome.config.xml.util.XmlDocumentReader;
-import org.openhab.extensionservice.marketplace.internal.MarketplaceProxy;
-import org.openhab.extensionservice.marketplace.internal.MarketplaceXMLReader;
 import org.openhab.extensionservice.marketplace.internal.model.Marketplace;
 import org.openhab.extensionservice.marketplace.internal.model.Node;
 import org.slf4j.Logger;
@@ -40,27 +40,27 @@
  * @author Kai Kreuzer - Initial contribution and API
  *
  */
+@NonNullByDefault
 public class MarketplaceProxy {
 
+    private static final String MP_URL = "https://marketplace.eclipse.org/taxonomy/term/4988%2C4396/api/p?client=org.eclipse.smarthome";
+    private static final long REFRESH_INTERVAL = 3600;
+    private static final long RETRY_DELAY = 60;
+
     private final Logger logger = LoggerFactory.getLogger(MarketplaceProxy.class);
 
-    private static final String MP_URL = "https://marketplace.eclipse.org/taxonomy/term/4988%2C4396/api/p?client=org.eclipse.smarthome";
+    private Node[] cachedNodes = new Node[0];
+    private final ScheduledExecutorService executorService = Executors.newSingleThreadScheduledExecutor();
+    private final ScheduledFuture<?> refreshJob;
     private final URL url;
-    private Node[] cachedNodes = null;
-    private long refresh_interval = 3600;
-    private long retry_delay = 60;
-    private ScheduledExecutorService executorService;
-    private ScheduledFuture<?> refreshJob;
 
     /**
      * Creates a new instance, which immediately schedules a synchronization with the marketplace content.
      */
     public MarketplaceProxy() {
         try {
             url = new URL(MP_URL);
-            this.executorService = Executors.newSingleThreadScheduledExecutor();
-            this.refreshJob = this.executorService.scheduleWithFixedDelay(() -> refresh(), 0, refresh_interval,
-                    TimeUnit.SECONDS);
+            refreshJob = executorService.scheduleWithFixedDelay(this::refresh, 0, REFRESH_INTERVAL, TimeUnit.SECONDS);
         } catch (MalformedURLException e) {
             throw new IllegalArgumentException("Something is very wrong - cannot instantiate URL " + MP_URL);
         }
@@ -72,7 +72,7 @@ public MarketplaceProxy() {
      * @return list of marketplace nodes
      */
     public List<Node> getNodes() {
-        return cachedNodes != null ? Arrays.asList(cachedNodes) : Collections.emptyList();
+        return Collections.unmodifiableList(Arrays.asList(cachedNodes));
     }
 
     /**
@@ -81,24 +81,26 @@ public List<Node> getNodes() {
     public synchronized void refresh() {
         XmlDocumentReader<Marketplace> reader = new MarketplaceXMLReader();
         try {
+            @Nullable
             Marketplace result = reader.readFromXML(url);
-            cachedNodes = result.categories[0].nodes;
+            if (result != null) {
+                cachedNodes = result.categories[0].nodes;
+            }
         } catch (Exception e) {
-            if (cachedNodes == null) {
+            if (cachedNodes.length == 0) {
                 logger.warn("Failed downloading Marketplace entries: {}", e.getMessage());
                 logger.warn("Retrying again in a minute");
-                this.executorService.schedule(() -> refresh(), retry_delay, TimeUnit.SECONDS);
+                executorService.schedule(this::refresh, RETRY_DELAY, TimeUnit.SECONDS);
             } else {
                 logger.debug("Cannot access IoT Marketplace - will continue to use cached results: {}", e.getMessage());
             }
         }
     }
 
     public void dispose() {
-        if (this.refreshJob != null && !this.refreshJob.isCancelled()) {
-            this.refreshJob.cancel(true);
-            this.refreshJob = null;
+        if (!refreshJob.isCancelled()) {
+            refreshJob.cancel(true);
         }
-        this.executorService.shutdown();
+        executorService.shutdown();
     }
 }
diff --git a/...src/main/java/org/openhab/extensionservice/marketplace/internal/MarketplaceXMLReader.java b/...src/main/java/org/openhab/extensionservice/marketplace/internal/MarketplaceXMLReader.java
@@ -12,6 +12,7 @@
  */
 package org.openhab.extensionservice.marketplace.internal;
 
+import org.eclipse.jdt.annotation.NonNullByDefault;
 import org.eclipse.smarthome.config.xml.util.XmlDocumentReader;
 import org.openhab.extensionservice.marketplace.internal.model.Category;
 import org.openhab.extensionservice.marketplace.internal.model.Marketplace;
@@ -25,18 +26,19 @@
  * @author Kai Kreuzer - Initial contribution and API
  *
  */
+@NonNullByDefault
 public class MarketplaceXMLReader extends XmlDocumentReader<Marketplace> {
 
     public MarketplaceXMLReader() {
         super.setClassLoader(Marketplace.class.getClassLoader());
     }
 
     @Override
-    public void registerConverters(XStream xstream) {
+    public void registerConverters(@NonNullByDefault({}) XStream xstream) {
     }
 
     @Override
-    public void registerAliases(XStream xstream) {
+    public void registerAliases(@NonNullByDefault({}) XStream xstream) {
         xstream.alias("marketplace", Marketplace.class);
         xstream.addImplicitArray(Marketplace.class, "categories");
         xstream.alias("category", Category.class);

diff --git a/...place/src/main/java/org/openhab/extensionservice/marketplace/internal/model/Category.java b/...place/src/main/java/org/openhab/extensionservice/marketplace/internal/model/Category.java
@@ -12,8 +12,6 @@
  */
 package org.openhab.extensionservice.marketplace.internal.model;
 
-import org.openhab.extensionservice.marketplace.internal.model.Node;
-
 /**
  * This is a category that holds the nodes as individual entries of the marketplace.
  *

diff --git a/...ce/src/main/java/org/openhab/extensionservice/marketplace/internal/model/Marketplace.java b/...ce/src/main/java/org/openhab/extensionservice/marketplace/internal/model/Marketplace.java
@@ -12,17 +12,18 @@
  */
 package org.openhab.extensionservice.marketplace.internal.model;
 
-import org.openhab.extensionservice.marketplace.internal.model.Category;
+import org.eclipse.jdt.annotation.NonNullByDefault;
 
 /**
  * This is the parent object that holds the category of the market.
  *
  * @author Kai Kreuzer - Initial contribution and API
  */
+@NonNullByDefault
 public class Marketplace {
 
     /**
      * The category of the marketplace
      */
-    public Category[] categories;
+    public Category[] categories = new Category[0];
 }