Loaders for single model queries

dbflow/src/main/java/com/raizlabs/android/dbflow/single/FlowModelLoader.java

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+package com.raizlabs.android.dbflow.single;
+
+import android.annotation.TargetApi;
+import android.content.Context;
+
+import com.raizlabs.android.dbflow.config.FlowManager;
+import com.raizlabs.android.dbflow.sql.queriable.Queriable;
+import com.raizlabs.android.dbflow.structure.Model;
+
+/**
+ * Load a single model from the database.
+ *
+ * @param <TModel>
+ */
+@TargetApi(11)
+public class FlowModelLoader <TModel extends Model>
+    extends FlowSingleModelLoader<TModel, TModel>
+{
+  public FlowModelLoader (Context context, Class<TModel> model, Queriable queriable)
+  {
+    super (context, model, FlowManager.getModelAdapter (model), queriable);
+  }
+}

dbflow/src/main/java/com/raizlabs/android/dbflow/single/FlowModelViewLoader.java

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+package com.raizlabs.android.dbflow.single;
+
+import android.annotation.TargetApi;
+import android.content.Context;
+
+import com.raizlabs.android.dbflow.config.FlowManager;
+import com.raizlabs.android.dbflow.sql.queriable.Queriable;
+import com.raizlabs.android.dbflow.structure.BaseModelView;
+import com.raizlabs.android.dbflow.structure.InstanceAdapter;
+import com.raizlabs.android.dbflow.structure.Model;
+
+/**
+ * Utility class to be added to DBFlow.
+ *
+ * @param <TModel>
+ */
+@TargetApi(11)
+public class FlowModelViewLoader <TModel extends Model, TModelView extends BaseModelView<TModel>>
+  extends FlowSingleModelLoader<TModel, TModelView>
+{
+  public FlowModelViewLoader (Context context,
+                              Class <TModel> model,
+                              Class <TModelView> modelView,
+                              Queriable queriable)
+  {
+    super (context, model, (InstanceAdapter<TModel, TModelView>) FlowManager.getModelViewAdapter (modelView), queriable);
+  }
+}

dbflow/src/main/java/com/raizlabs/android/dbflow/single/FlowQueryModelLoader.java

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+package com.raizlabs.android.dbflow.single;
+
+import android.annotation.TargetApi;
+import android.content.Context;
+
+import com.raizlabs.android.dbflow.config.FlowManager;
+import com.raizlabs.android.dbflow.sql.queriable.Queriable;
+import com.raizlabs.android.dbflow.structure.BaseQueryModel;
+
+/**
+ * Utility class to be added to DBFlow.
+ *
+ * @param <TQueryModel>
+ */
+@TargetApi(11)
+public class FlowQueryModelLoader <TQueryModel extends BaseQueryModel>
+  extends FlowSingleModelLoader<TQueryModel, TQueryModel>
+{
+  public FlowQueryModelLoader (Context context,
+                               Class <TQueryModel> model,
+                               Queriable queriable)
+  {
+    super (context, model, FlowManager.getQueryModelAdapter (model), queriable);
+    this.setObserveModel (false);
+  }
+}

dbflow/src/main/java/com/raizlabs/android/dbflow/single/FlowSingleModelLoader.java

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+package com.raizlabs.android.dbflow.single;
+
+import android.annotation.TargetApi;
+import android.content.Context;
+import android.database.Cursor;
+import android.net.Uri;
+import android.support.v4.content.AsyncTaskLoader;
+
+import com.raizlabs.android.dbflow.runtime.FlowContentObserver;
+import com.raizlabs.android.dbflow.sql.queriable.Queriable;
+import com.raizlabs.android.dbflow.structure.InstanceAdapter;
+import com.raizlabs.android.dbflow.structure.Model;
+
+import java.util.HashSet;
+
+/**
+ * Utility class to be added to DBFlow.
+ *
+ * @param <TModel>
+ */
+@TargetApi(11)
+public abstract class FlowSingleModelLoader <TModel extends Model, TTable extends Model>
+    extends AsyncTaskLoader<TModel>
+{
+  /// Models to be observed for changes.
+  private final Class<TModel> mModel;
+  private final InstanceAdapter<TModel, TTable> mAdapter;
+
+  /// Queriable operation that the loader executes.
+  private Queriable mQueriable;
+
+  /// Cursor for the loader.
+  private TModel mResult;
+
+  private boolean mObserveModel = true;
+
+  private static final String TAG = "FlowSingleModelLoader";
+
+  protected HashSet<? extends Model> mModels = new HashSet<> ();
+
+  private class ForceLoadContentObserver extends FlowContentObserver
+  {
+    @Override
+    public boolean deliverSelfNotifications ()
+    {
+      return true;
+    }
+
+    @Override
+    public void onChange (boolean selfChange)
+    {
+      super.onChange (selfChange);
+
+      onContentChanged ();
+    }
+
+    @Override
+    public void onChange (boolean selfChange, Uri uri)
+    {
+      super.onChange (selfChange, uri);
+
+      onContentChanged ();
+    }
+  }
+
+  protected final FlowContentObserver mObserver = new ForceLoadContentObserver ();
+
+  protected FlowSingleModelLoader (Context context,
+                                   Class<TModel> model,
+                                   InstanceAdapter<TModel, TTable> adapter,
+                                   Queriable queriable)
+  {
+    super (context);
+
+    this.mQueriable = queriable;
+    this.mModel = model;
+    this.mAdapter = adapter;
+  }
+
+  /* Runs on a worker thread */
+  @Override
+  public TModel loadInBackground ()
+  {
+    Cursor cursor = this.mQueriable.query ();
+
+    if (cursor == null || !cursor.moveToFirst ())
+      return null;
+
+    TModel model = this.mAdapter.newInstance ();
+    this.mAdapter.loadFromCursor (cursor, model);
+
+    return model;
+  }
+
+  /* Runs on the UI thread */
+  @Override
+  public void deliverResult (TModel result)
+  {
+    this.mResult = result;
+
+    if (this.isStarted ())
+      super.deliverResult (result);
+  }
+
+  /**
+   * Starts an asynchronous load of the contacts list data. When the result is ready the callbacks
+   * will be called on the UI thread. If a previous load has been completed and is still valid the
+   * result may be passed to the callbacks immediately.
+   * <p>
+   * Must be called from the UI thread
+   */
+  @Override
+  protected void onStartLoading ()
+  {
+    if (mResult != null)
+      this.deliverResult (mResult);
+
+    // Start watching for changes to the model.
+    if (this.mObserveModel)
+      this.registerForContentChanges (this.mModel);
+
+    if (this.takeContentChanged () || this.mResult == null)
+      this.forceLoad ();
+  }
+
+  /**
+   * Must be called from the UI thread
+   */
+  @Override
+  protected void onStopLoading ()
+  {
+    this.cancelLoad ();
+  }
+
+  @Override
+  protected void onReset ()
+  {
+    super.onReset ();
+
+    // Ensure the loader is stopped
+    this.onStopLoading ();
+
+    if (this.mResult != null)
+      this.mResult = null;
+
+    // Unregister the loader for content changes.
+    this.mObserver.unregisterForContentChanges (this.getContext ());
+  }
+
+  public Class<TModel> getModel ()
+  {
+    return this.mModel;
+  }
+
+  public void setObserveModel (boolean observeModel)
+  {
+    this.mObserveModel = observeModel;
+  }
+
+  public void registerForContentChanges (Class<? extends Model> model)
+  {
+    if (this.mModels.contains (model))
+      return;
+
+    this.mObserver.registerForContentChanges (this.getContext (), model);
+  }
+}