Add RxJava2 support

DaoCore/build.gradle

@@ -20,6 +20,7 @@ dependencies {
     compileOnly 'com.google.android:support-v4:r7'
 
     compileOnly 'io.reactivex:rxjava:1.1.8'
+    compile 'io.reactivex.rxjava2:rxjava:2.0.9'
 
     compileOnly files('libs/sqlcipher.jar')
 }

DaoCore/src/main/java/org/greenrobot/greendao/AbstractDao.java

@@ -33,6 +33,7 @@
 import org.greenrobot.greendao.query.Query;
 import org.greenrobot.greendao.query.QueryBuilder;
 import org.greenrobot.greendao.rx.RxDao;
+import org.greenrobot.greendao.rx2.Rx2Dao;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -73,6 +74,9 @@ public abstract class AbstractDao<T, K> {
     private volatile RxDao<T, K> rxDao;
     private volatile RxDao<T, K> rxDaoPlain;
 
+    private volatile Rx2Dao<T, K> rx2Dao;
+    private volatile Rx2Dao<T, K> rx2DaoPlain;
+
     public AbstractDao(DaoConfig config) {
         this(config, null);
     }
@@ -964,6 +968,34 @@ public RxDao<T, K> rx() {
         return rxDao;
     }
 
+    /**
+     * The returned Rx2Dao is a special DAO that let's you interact with Rx Observables without any Scheduler set
+     * for subscribeOn.
+     *
+     * @see #rx2()
+     */
+    @Experimental
+    public Rx2Dao<T, K> rx2Plain() {
+        if (rx2DaoPlain == null) {
+            rx2DaoPlain = new Rx2Dao<>(this);
+        }
+        return rx2DaoPlain;
+    }
+
+    /**
+     * The returned Rx2Dao is a special DAO that let's you interact with Rx Observables using RX's IO scheduler for
+     * subscribeOn.
+     *
+     * @see #rx2Plain()
+     */
+    @Experimental
+    public Rx2Dao<T, K> rx2() {
+        if (rx2Dao == null) {
+            rx2Dao = new Rx2Dao<>(this, io.reactivex.schedulers.Schedulers.io());
+        }
+        return rx2Dao;
+    }
+
     /** Gets the SQLiteDatabase for custom database access. Not needed for greenDAO entities. */
     public Database getDatabase() {
         return db;

DaoCore/src/main/java/org/greenrobot/greendao/rx2/Rx2Base.java

@@ -0,0 +1,57 @@
+package org.greenrobot.greendao.rx2;
+
+import org.greenrobot.greendao.annotation.apihint.Experimental;
+import org.greenrobot.greendao.annotation.apihint.Internal;
+
+import java.util.concurrent.Callable;
+
+import io.reactivex.Observable;
+import io.reactivex.Scheduler;
+
+/**
+ * Created by Zhang Tingkuo.
+ * Date: 2017-04-28
+ * Time: 14:14
+ */
+@Internal
+class Rx2Base {
+
+    protected final Scheduler mScheduler;
+
+    /**
+     * No default scheduler.
+     */
+    public Rx2Base() {
+        mScheduler = null;
+    }
+
+    /**
+     * Sets the default scheduler, which is used to configure returned observables with
+     * {@link Observable#subscribeOn(Scheduler)}.
+     */
+    @Experimental
+    Rx2Base(Scheduler scheduler) {
+        mScheduler = scheduler;
+    }
+
+    /**
+     * The default scheduler (or null) used for wrapping.
+     */
+    @Experimental
+    public Scheduler getScheduler() {
+        return mScheduler;
+    }
+
+    protected <R> Observable<R> wrap(Callable<R> callable) {
+        return wrap(Rx2Utils.fromCallable(callable));
+    }
+
+    protected <R> Observable<R> wrap(Observable<R> observable) {
+        if (mScheduler != null) {
+            return observable.subscribeOn(mScheduler);
+        } else {
+            return observable;
+        }
+    }
+
+}