diff --git a/easymvp-rx2-api/src/main/java/easymvp/usecase/FlowableUseCase.java b/easymvp-rx2-api/src/main/java/easymvp/usecase/FlowableUseCase.java
new file mode 100644
index 0000000..c1a05e4
--- /dev/null
+++ b/easymvp-rx2-api/src/main/java/easymvp/usecase/FlowableUseCase.java
@@ -0,0 +1,40 @@
+package easymvp.usecase;
+
+import javax.annotation.Nullable;
+
+import easymvp.executer.PostExecutionThread;
+import easymvp.executer.UseCaseExecutor;
+import io.reactivex.Flowable;
+import io.reactivex.FlowableTransformer;
+
+/**
+ * @author Saeed Masoumi (s-masoumi@live.com)
+ */
+
+public abstract class FlowableUseCase<R, Q> extends UseCase<Flowable, Q> {
+    private final FlowableTransformer<? super R, ? extends R> schedulersTransformer;
+
+    public FlowableUseCase(final UseCaseExecutor useCaseExecutor,
+                           final PostExecutionThread postExecutionThread) {
+        super(useCaseExecutor, postExecutionThread);
+        schedulersTransformer = new FlowableTransformer<R, R>() {
+            @Override
+            public Flowable<R> apply(Flowable<R> rObservable) {
+                return rObservable.subscribeOn(useCaseExecutor.getScheduler())
+                        .observeOn(postExecutionThread.getScheduler());
+            }
+        };
+    }
+
+    @Override
+    public Flowable<R> execute(@Nullable Q param) {
+        return interact(param).compose(getSchedulersTransformer());
+    }
+
+    @Override
+    protected abstract Flowable<R> interact(@Nullable Q param);
+
+    private FlowableTransformer<? super R, ? extends R> getSchedulersTransformer() {
+        return schedulersTransformer;
+    }
+}
diff --git a/easymvp-rx2-api/src/main/java/easymvp/usecase/MaybeUseCase.java b/easymvp-rx2-api/src/main/java/easymvp/usecase/MaybeUseCase.java
new file mode 100644
index 0000000..ff85266
--- /dev/null
+++ b/easymvp-rx2-api/src/main/java/easymvp/usecase/MaybeUseCase.java
@@ -0,0 +1,40 @@
+package easymvp.usecase;
+
+import javax.annotation.Nullable;
+
+import easymvp.executer.PostExecutionThread;
+import easymvp.executer.UseCaseExecutor;
+import io.reactivex.Maybe;
+import io.reactivex.MaybeTransformer;
+
+/**
+ * @author Saeed Masoumi (s-masoumi@live.com)
+ */
+
+public abstract class MaybeUseCase<R, Q> extends UseCase<Maybe, Q> {
+    private final MaybeTransformer<? super R, ? extends R> schedulersTransformer;
+
+    public MaybeUseCase(final UseCaseExecutor useCaseExecutor,
+                        final PostExecutionThread postExecutionThread) {
+        super(useCaseExecutor, postExecutionThread);
+        schedulersTransformer = new MaybeTransformer<R, R>() {
+            @Override
+            public Maybe<R> apply(Maybe<R> single) {
+                return single.subscribeOn(useCaseExecutor.getScheduler())
+                        .observeOn(postExecutionThread.getScheduler());
+            }
+        };
+    }
+
+    @Override
+    public Maybe execute(@Nullable Q param) {
+        return interact(param).compose(getSchedulersTransformer());
+    }
+
+    @Override
+    protected abstract Maybe<R> interact(@Nullable Q param);
+
+    private MaybeTransformer<? super R, ? extends R> getSchedulersTransformer() {
+        return schedulersTransformer;
+    }
+}
diff --git a/easymvp-rx2-api/src/main/java/easymvp/usecase/SingleUseCase.java b/easymvp-rx2-api/src/main/java/easymvp/usecase/SingleUseCase.java
new file mode 100644
index 0000000..96ff7dd
--- /dev/null
+++ b/easymvp-rx2-api/src/main/java/easymvp/usecase/SingleUseCase.java
@@ -0,0 +1,39 @@
+package easymvp.usecase;
+
+import easymvp.executer.PostExecutionThread;
+import easymvp.executer.UseCaseExecutor;
+import io.reactivex.Single;
+import io.reactivex.SingleTransformer;
+import io.reactivex.annotations.Nullable;
+
+/**
+ * @author Saeed Masoumi (s-masoumi@live.com)
+ */
+
+public abstract class SingleUseCase<R, Q> extends UseCase<Single, Q> {
+    private final SingleTransformer<? super R, ? extends R> schedulersTransformer;
+
+    public SingleUseCase(final UseCaseExecutor useCaseExecutor,
+                         final PostExecutionThread postExecutionThread) {
+        super(useCaseExecutor, postExecutionThread);
+        schedulersTransformer = new SingleTransformer<R, R>() {
+            @Override
+            public Single<R> apply(Single<R> single) {
+                return single.subscribeOn(useCaseExecutor.getScheduler())
+                        .observeOn(postExecutionThread.getScheduler());
+            }
+        };
+    }
+
+    @Override
+    public Single<R> execute(@Nullable Q param) {
+        return interact(param).compose(getSchedulersTransformer());
+    }
+
+    @Override
+    protected abstract Single<R> interact(@Nullable Q param);
+
+    private SingleTransformer<? super R, ? extends R> getSchedulersTransformer() {
+        return schedulersTransformer;
+    }
+}
diff --git a/easymvp-rx2-api/src/main/java/easymvp/usecase/UseCase.java b/easymvp-rx2-api/src/main/java/easymvp/usecase/UseCase.java
index 1ef7549..6d334d4 100644
--- a/easymvp-rx2-api/src/main/java/easymvp/usecase/UseCase.java
+++ b/easymvp-rx2-api/src/main/java/easymvp/usecase/UseCase.java
@@ -7,6 +7,14 @@
 import javax.annotation.Nullable;
 
 /**
+ * Each {@code UseCase} of the system orchestrate the flow of data to and from the entities.
+ * <p>
+ * Outer layers of system can execute use cases by calling {@link #execute(Object)}} method. Also
+ * you can use {@link #useCaseExecutor} to execute the job in a background thread and {@link
+ * #postExecutionThread} to post the result to another thread(usually UI thread).
+ *
+ * @param <P> The response type of a use case.
+ * @param <Q> The request type of a use case.
  * Created by megrez on 2017/3/12.
  */
 public abstract class UseCase<P,Q> {