Merge branch '38-network-state-provider' into 'sync'

#38 Add NetworkStateProvider API.

See merge request objectbox/objectbox-java!47

Author: greenrobot-team

objectbox-java/src/main/java/io/objectbox/sync/ConnectivityMonitor.java

@@ -0,0 +1,52 @@
+package io.objectbox.sync;
+
+import javax.annotation.Nullable;
+
+/**
+ * Used by {@link SyncClient} to observe connectivity changes.
+ * <p>
+ * Implementations are provided by a {@link io.objectbox.sync.internal.Platform platform}.
+ */
+public abstract class ConnectivityMonitor {
+
+    @Nullable
+    private SyncClient syncClient;
+
+    void setObserver(SyncClient syncClient) {
+        //noinspection ConstantConditions Annotations do not enforce non-null.
+        if (syncClient == null) {
+            throw new IllegalArgumentException("Sync client must not be null");
+        }
+        this.syncClient = syncClient;
+        onObserverSet();
+    }
+
+    void removeObserver() {
+        this.syncClient = null;
+        onObserverRemoved();
+    }
+
+    /**
+     * Called right after the observer was set.
+     */
+    public void onObserverSet() {
+    }
+
+    /**
+     * Called right after the observer was removed.
+     */
+    public void onObserverRemoved() {
+    }
+
+    /**
+     * Notifies the observer that a connection is available.
+     * Implementers should call this once a working network connection is available.
+     */
+    public final void notifyConnectionAvailable() {
+        SyncClient syncClient = this.syncClient;
+        if (syncClient != null) {
+            syncClient.notifyConnectionAvailable();
+        }
+    }
+
+}

objectbox-java/src/main/java/io/objectbox/sync/SyncBuilder.java

@@ -2,6 +2,7 @@
 
 import io.objectbox.BoxStore;
 import io.objectbox.annotation.apihint.Experimental;
+import io.objectbox.sync.internal.Platform;
 
 import javax.annotation.Nullable;
 
@@ -13,6 +14,7 @@
 @SuppressWarnings({"unused", "WeakerAccess"})
 public class SyncBuilder {
 
+    final Platform platform;
     final BoxStore boxStore;
     final String url;
     final SyncCredentials credentials;
@@ -64,6 +66,7 @@ public SyncBuilder(BoxStore boxStore, String url, SyncCredentials credentials) {
             throw new IllegalStateException(
                     "This ObjectBox library (JNI) does not include sync. Please update your dependencies.");
         }
+        this.platform = Platform.findPlatform();
         this.boxStore = boxStore;
         this.url = url;
         this.credentials = credentials;

objectbox-java/src/main/java/io/objectbox/sync/SyncClient.java

@@ -123,4 +123,12 @@ public interface SyncClient extends Closeable {
     @Experimental
     void requestFullSync();
 
+    /**
+     * Lets the sync client know that a working network connection
+     * is available.
+     * <p>
+     * This can help speed up reconnecting to the sync server.
+     */
+    void notifyConnectionAvailable();
+
 }

objectbox-java/src/main/java/io/objectbox/sync/SyncClientImpl.java

@@ -18,6 +18,8 @@ public class SyncClientImpl implements SyncClient {
 
     private final String serverUrl;
     private final InternalListener internalListener;
+    @Nullable
+    private final ConnectivityMonitor connectivityMonitor;
 
     private volatile long handle;
     @Nullable
@@ -27,6 +29,7 @@ public class SyncClientImpl implements SyncClient {
 
     SyncClientImpl(SyncBuilder builder) {
         this.serverUrl = builder.url;
+        this.connectivityMonitor = builder.platform.getConnectivityMonitor();
 
         long boxStoreHandle = InternalAccess.getHandle(builder.boxStore);
         this.handle = nativeCreate(boxStoreHandle, serverUrl, builder.certificatePath);
@@ -123,6 +126,9 @@ public boolean awaitFirstLogin(long millisToWait) {
     public synchronized void start() {
         nativeStart(handle);
         started = true;
+        if (connectivityMonitor != null) {
+            connectivityMonitor.setObserver(this);
+        }
     }
 
     @Override
@@ -132,6 +138,10 @@ public boolean isStarted() {
 
     @Override
     public synchronized void stop() {
+        if (connectivityMonitor != null) {
+            connectivityMonitor.removeObserver();
+        }
+
         long handleToStop = this.handle;
         if (handleToStop != 0) {
             nativeStop(handleToStop);
@@ -141,6 +151,10 @@ public synchronized void stop() {
 
     @Override
     public void close() {
+        if (connectivityMonitor != null) {
+            connectivityMonitor.removeObserver();
+        }
+
         long handleToDelete;
         synchronized (this) {
             handleToDelete = this.handle;
@@ -188,6 +202,11 @@ public void cancelUpdates() {
         nativeCancelUpdates(handle);
     }
 
+    @Override
+    public void notifyConnectionAvailable() {
+        nativeTriggerReconnect(handle);
+    }
+
     private void checkNotNull(Object object, String message) {
         //noinspection ConstantConditions Non-null annotation does not enforce, so check for null.
         if (object == null) {
@@ -231,6 +250,9 @@ private void checkNotNull(Object object, String message) {
     /** (Optional) Pause sync updates. */
     private native void nativeCancelUpdates(long handle);
 
+    /** Hints to the native client that an active network connection is available. */
+    private native void nativeTriggerReconnect(long handle);
+
     private class InternalListener implements SyncClientListener {
         private final CountDownLatch firstLoginLatch = new CountDownLatch(1);
 

objectbox-java/src/main/java/io/objectbox/sync/internal/Platform.java

@@ -0,0 +1,52 @@
+package io.objectbox.sync.internal;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+import javax.annotation.Nullable;
+
+import io.objectbox.BoxStore;
+import io.objectbox.sync.ConnectivityMonitor;
+
+/**
+ * Provides access to platform-specific features.
+ */
+public class Platform {
+
+    public static Platform findPlatform() {
+        // Android
+        Object contextInstance = BoxStore.context;
+        if (contextInstance != null) {
+            Throwable throwable = null;
+
+            // Note: do not catch Exception as it will swallow exceptions useful for debugging.
+            // Also can't catch ReflectiveOperationException, is K+ (19+) on Android.
+            // noinspection TryWithIdenticalCatches Requires Android K+ (19+).
+            try {
+                Class<?> contextClass = Class.forName("android.content.Context");
+                Class<?> platformClass = Class.forName("io.objectbox.android.internal.AndroidPlatform");
+                Method create = platformClass.getMethod("create", contextClass);
+                return (Platform) create.invoke(null, contextInstance);
+            } catch (NoSuchMethodException e) {
+                throwable = e;
+            } catch (IllegalAccessException e) {
+                throwable = e;
+            } catch (InvocationTargetException e) {
+                throwable = e;
+            } catch (ClassNotFoundException ignored) {
+                // Android API or library not in classpath.
+            }
+
+            if (throwable != null) {
+                throw new RuntimeException("AndroidPlatform could not be created.", throwable);
+            }
+        }
+
+        return new Platform();
+    }
+
+    @Nullable
+    public ConnectivityMonitor getConnectivityMonitor() {
+        return null;
+    }
+}

tests/objectbox-java-test/src/test/java/io/objectbox/FunctionalTestSuite.java

@@ -27,6 +27,9 @@
 import io.objectbox.relation.ToManyStandaloneTest;
 import io.objectbox.relation.ToManyTest;
 import io.objectbox.relation.ToOneTest;
+import io.objectbox.sync.ConnectivityMonitorTest;
+import io.objectbox.sync.PlatformTest;
+
 import org.junit.runner.RunWith;
 import org.junit.runners.Suite;
 import org.junit.runners.Suite.SuiteClasses;
@@ -37,13 +40,15 @@
         BoxTest.class,
         BoxStoreTest.class,
         BoxStoreBuilderTest.class,
+        ConnectivityMonitorTest.class,
         CursorTest.class,
         CursorBytesTest.class,
         DebugCursorTest.class,
         LazyListTest.class,
         NonArgConstructorTest.class,
         IndexReaderRenewTest.class,
         ObjectClassObserverTest.class,
+        PlatformTest.class,
         PropertyQueryTest.class,
         QueryFilterComparatorTest.class,
         QueryObserverTest.class,