Observable.from: refactor varargs to overloads

#359 Varargs cause compiler warnings

Author: benjchristensen

language-adaptors/rxjava-scala/src/test/scala/rx/lang/scala/RxImplicitsTests.scala

@@ -75,7 +75,7 @@ class UnitTestSuite extends JUnitSuite {
     }
 
     @Test def testSingleOrDefault {
-        assertEquals(0, Observable.from[Int]().toBlockingObservable.singleOrDefault(0))
+        assertEquals(0, Observable.empty[Int]().toBlockingObservable.singleOrDefault(0))
         assertEquals(1, Observable.from(1).toBlockingObservable.singleOrDefault(0))
         try {
             Observable.from(1, 2, 3).toBlockingObservable.singleOrDefault(0)
@@ -232,13 +232,13 @@ class UnitTestSuite extends JUnitSuite {
     @Test def testLastOrDefault {
         val observable = Observable.from(1, 2, 3, 4)
         assertEquals(4, observable.toBlockingObservable.lastOrDefault(5))
-        assertEquals(5, Observable.from[Int]().toBlockingObservable.lastOrDefault(5))
+        assertEquals(5, Observable.empty[Int]().toBlockingObservable.lastOrDefault(5))
     }
 
     @Test def testLastOrDefaultPredicate {
         val observable = Observable.from(1, 2, 3, 4)
         assertEquals(3, observable.toBlockingObservable.lastOrDefault(5, isOdd))
-        assertEquals(5, Observable.from[Int]().toBlockingObservable.lastOrDefault(5, isOdd))
+        assertEquals(5, Observable.empty[Int]().toBlockingObservable.lastOrDefault(5, isOdd))
     }
 
     @Test def testMap {

rxjava-core/src/main/java/rx/Observable.java

@@ -18,6 +18,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
@@ -529,24 +530,322 @@ public static <T> Observable<T> error(Throwable exception) {
     public static <T> Observable<T> from(Iterable<? extends T> iterable) {
         return create(OperationToObservableIterable.toObservableIterable(iterable));
     }
-
+    
     /**
      * Converts an Array into an Observable.
      * <p>
      * <img width="640" src="https://github.com/Netflix/RxJava/wiki/images/rx-operators/from.png">
      * 
+     * <p>Implementation note: the entire iterable sequence will be immediately emitted each time an {@link Observer} subscribes. Since this occurs before the {@link Subscription} is returned,
+     * it in not possible to unsubscribe from the sequence before it completes.
+     * 
+     * @param array
+     *            the source sequence
+     * @param <T>
+     *            the type of items in the {@link Iterable} sequence and the type of items to be
+     *            emitted by the resulting Observable
+     * @return an Observable that emits each item in the source {@link Iterable} sequence
+     */
+    public static <T> Observable<T> from(T[] items) {
+        return create(OperationToObservableIterable.toObservableIterable(Arrays.asList(items)));
+    }
+
+    /**
+     * Converts a series of items into an Observable.
+     * <p>
+     * <img width="640" src="https://github.com/Netflix/RxJava/wiki/images/rx-operators/from.png">
+     * 
      * <p>Implementation note: the entire array will be immediately emitted each time an {@link Observer} subscribes. Since this occurs before the {@link Subscription} is returned,
      * it in not possible to unsubscribe from the sequence before it completes.
      * 
-     * @param items
-     *            the source Array
+     * @param t1
+     *            item
      * @param <T>
      *            the type of items in the Array, and the type of items to be emitted by the
      *            resulting Observable
      * @return an Observable that emits each item in the source Array
      */
-    public static <T> Observable<T> from(T... items) {
-        return create(OperationToObservableIterable.toObservableIterable(Arrays.asList(items)));
+    @SuppressWarnings("unchecked")
+    // suppress unchecked because we are using varargs inside the method
+    public static <T> Observable<T> from(T t1) {
+        return from(Arrays.asList(t1));
+    }
+
+    /**
+     * Converts a series of items into an Observable.
+     * <p>
+     * <img width="640" src="https://github.com/Netflix/RxJava/wiki/images/rx-operators/from.png">
+     * 
+     * <p>Implementation note: the entire array will be immediately emitted each time an {@link Observer} subscribes. Since this occurs before the {@link Subscription} is returned,
+     * it in not possible to unsubscribe from the sequence before it completes.
+     * 
+     * @param t1
+     *            item
+     * @param t2
+     *            item
+     * @param <T>
+     *            the type of items in the Array, and the type of items to be emitted by the
+     *            resulting Observable
+     * @return an Observable that emits each item in the source Array
+     */
+    @SuppressWarnings("unchecked")
+    // suppress unchecked because we are using varargs inside the method
+    public static <T> Observable<T> from(T t1, T t2) {
+        return from(Arrays.asList(t1, t2));
+    }
+
+    /**
+     * Converts a series of items into an Observable.
+     * <p>
+     * <img width="640" src="https://github.com/Netflix/RxJava/wiki/images/rx-operators/from.png">
+     * 
+     * <p>Implementation note: the entire array will be immediately emitted each time an {@link Observer} subscribes. Since this occurs before the {@link Subscription} is returned,
+     * it in not possible to unsubscribe from the sequence before it completes.
+     * 
+     * @param t1
+     *            item
+     * @param t2
+     *            item
+     * @param t3
+     *            item
+     * @param <T>
+     *            the type of items in the Array, and the type of items to be emitted by the
+     *            resulting Observable
+     * @return an Observable that emits each item in the source Array
+     */
+    @SuppressWarnings("unchecked")
+    // suppress unchecked because we are using varargs inside the method
+    public static <T> Observable<T> from(T t1, T t2, T t3) {
+        return from(Arrays.asList(t1, t2, t3));
+    }
+
+    /**
+     * Converts a series of items into an Observable.
+     * <p>
+     * <img width="640" src="https://github.com/Netflix/RxJava/wiki/images/rx-operators/from.png">
+     * 
+     * <p>Implementation note: the entire array will be immediately emitted each time an {@link Observer} subscribes. Since this occurs before the {@link Subscription} is returned,
+     * it in not possible to unsubscribe from the sequence before it completes.
+     * 
+     * @param t1
+     *            item
+     * @param t2
+     *            item
+     * @param t3
+     *            item
+     * @param t4
+     *            item
+     * @param <T>
+     *            the type of items in the Array, and the type of items to be emitted by the
+     *            resulting Observable
+     * @return an Observable that emits each item in the source Array
+     */
+    @SuppressWarnings("unchecked")
+    // suppress unchecked because we are using varargs inside the method
+    public static <T> Observable<T> from(T t1, T t2, T t3, T t4) {
+        return from(Arrays.asList(t1, t2, t3, t4));
+    }
+
+    /**
+     * Converts a series of items into an Observable.
+     * <p>
+     * <img width="640" src="https://github.com/Netflix/RxJava/wiki/images/rx-operators/from.png">
+     * 
+     * <p>Implementation note: the entire array will be immediately emitted each time an {@link Observer} subscribes. Since this occurs before the {@link Subscription} is returned,
+     * it in not possible to unsubscribe from the sequence before it completes.
+     * 
+     * @param t1
+     *            item
+     * @param t2
+     *            item
+     * @param t3
+     *            item
+     * @param t4
+     *            item
+     * @param t5
+     *            item
+     * @param <T>
+     *            the type of items in the Array, and the type of items to be emitted by the
+     *            resulting Observable
+     * @return an Observable that emits each item in the source Array
+     */
+    @SuppressWarnings("unchecked")
+    // suppress unchecked because we are using varargs inside the method
+    public static <T> Observable<T> from(T t1, T t2, T t3, T t4, T t5) {
+        return from(Arrays.asList(t1, t2, t3, t4, t5));
+    }
+
+    /**
+     * Converts a series of items into an Observable.
+     * <p>
+     * <img width="640" src="https://github.com/Netflix/RxJava/wiki/images/rx-operators/from.png">
+     * 
+     * <p>Implementation note: the entire array will be immediately emitted each time an {@link Observer} subscribes. Since this occurs before the {@link Subscription} is returned,
+     * it in not possible to unsubscribe from the sequence before it completes.
+     * 
+     * @param t1
+     *            item
+     * @param t2
+     *            item
+     * @param t3
+     *            item
+     * @param t4
+     *            item
+     * @param t5
+     *            item
+     * @param t6
+     *            item
+     * @param <T>
+     *            the type of items in the Array, and the type of items to be emitted by the
+     *            resulting Observable
+     * @return an Observable that emits each item in the source Array
+     */
+    @SuppressWarnings("unchecked")
+    // suppress unchecked because we are using varargs inside the method
+    public static <T> Observable<T> from(T t1, T t2, T t3, T t4, T t5, T t6) {
+        return from(Arrays.asList(t1, t2, t3, t4, t5, t6));
+    }
+
+    /**
+     * Converts a series of items into an Observable.
+     * <p>
+     * <img width="640" src="https://github.com/Netflix/RxJava/wiki/images/rx-operators/from.png">
+     * 
+     * <p>Implementation note: the entire array will be immediately emitted each time an {@link Observer} subscribes. Since this occurs before the {@link Subscription} is returned,
+     * it in not possible to unsubscribe from the sequence before it completes.
+     * 
+     * @param t1
+     *            item
+     * @param t2
+     *            item
+     * @param t3
+     *            item
+     * @param t4
+     *            item
+     * @param t5
+     *            item
+     * @param t6
+     *            item
+     * @param t7
+     *            item
+     * @param <T>
+     *            the type of items in the Array, and the type of items to be emitted by the
+     *            resulting Observable
+     * @return an Observable that emits each item in the source Array
+     */
+    @SuppressWarnings("unchecked")
+    // suppress unchecked because we are using varargs inside the method
+    public static <T> Observable<T> from(T t1, T t2, T t3, T t4, T t5, T t6, T t7) {
+        return from(Arrays.asList(t1, t2, t3, t4, t5, t6, t7));
+    }
+
+    /**
+     * Converts a series of items into an Observable.
+     * <p>
+     * <img width="640" src="https://github.com/Netflix/RxJava/wiki/images/rx-operators/from.png">
+     * 
+     * <p>Implementation note: the entire array will be immediately emitted each time an {@link Observer} subscribes. Since this occurs before the {@link Subscription} is returned,
+     * it in not possible to unsubscribe from the sequence before it completes.
+     * 
+     * @param t1
+     *            item
+     * @param t2
+     *            item
+     * @param t3
+     *            item
+     * @param t4
+     *            item
+     * @param t5
+     *            item
+     * @param t6
+     *            item
+     * @param t7
+     *            item
+     * @param t8
+     *            item
+     * @param <T>
+     *            the type of items in the Array, and the type of items to be emitted by the
+     *            resulting Observable
+     * @return an Observable that emits each item in the source Array
+     */
+    @SuppressWarnings("unchecked")
+    // suppress unchecked because we are using varargs inside the method
+    public static <T> Observable<T> from(T t1, T t2, T t3, T t4, T t5, T t6, T t7, T t8) {
+        return from(Arrays.asList(t1, t2, t3, t4, t5, t6, t7, t8));
+    }
+
+    /**
+     * Converts a series of items into an Observable.
+     * <p>
+     * <img width="640" src="https://github.com/Netflix/RxJava/wiki/images/rx-operators/from.png">
+     * 
+     * <p>Implementation note: the entire array will be immediately emitted each time an {@link Observer} subscribes. Since this occurs before the {@link Subscription} is returned,
+     * it in not possible to unsubscribe from the sequence before it completes.
+     * 
+     * @param t1
+     *            item
+     * @param t2
+     *            item
+     * @param t3
+     *            item
+     * @param t4
+     *            item
+     * @param t5
+     *            item
+     * @param t6
+     *            item
+     * @param t7
+     *            item
+     * @param t8
+     *            item
+     * @param t9
+     *            item
+     * @param <T>
+     *            the type of items in the Array, and the type of items to be emitted by the
+     *            resulting Observable
+     * @return an Observable that emits each item in the source Array
+     */
+    @SuppressWarnings("unchecked")
+    // suppress unchecked because we are using varargs inside the method
+    public static <T> Observable<T> from(T t1, T t2, T t3, T t4, T t5, T t6, T t7, T t8, T t9) {
+        return from(Arrays.asList(t1, t2, t3, t4, t5, t6, t7, t8, t9));
+    }
+    
+    /**
+     * Converts a series of items into an Observable.
+     * <p>
+     * <img width="640" src="https://github.com/Netflix/RxJava/wiki/images/rx-operators/from.png">
+     * 
+     * <p>Implementation note: the entire array will be immediately emitted each time an {@link Observer} subscribes. Since this occurs before the {@link Subscription} is returned,
+     * it in not possible to unsubscribe from the sequence before it completes.
+     * 
+     * @param t1
+     *            item
+     * @param t2
+     *            item
+     * @param t3
+     *            item
+     * @param t4
+     *            item
+     * @param t5
+     *            item
+     * @param t6
+     *            item
+     * @param t7
+     *            item
+     * @param t8
+     *            item
+     * @param t10
+     *            item
+     * @param <T>
+     *            the type of items in the Array, and the type of items to be emitted by the
+     *            resulting Observable
+     * @return an Observable that emits each item in the source Array
+     */
+    @SuppressWarnings("unchecked")
+    // suppress unchecked because we are using varargs inside the method
+    public static <T> Observable<T> from(T t1, T t2, T t3, T t4, T t5, T t6, T t7, T t8, T t9, T t10) {
+        return from(Arrays.asList(t1, t2, t3, t4, t5, t6, t7, t8, t9, t10));
     }
 
     /**

rxjava-core/src/main/java/rx/observables/BlockingObservable.java

@@ -387,7 +387,7 @@ public void testLast() {
 
         @Test
         public void testLastEmptyObservable() {
-            BlockingObservable<Object> obs = BlockingObservable.from(Observable.from());
+            BlockingObservable<Object> obs = BlockingObservable.from(Observable.empty());
 
             assertNull(obs.last());
         }
@@ -412,7 +412,7 @@ public void testLastOrDefault1() {
 
         @Test
         public void testLastOrDefault2() {
-            BlockingObservable<Object> observable = BlockingObservable.from(Observable.from());
+            BlockingObservable<Object> observable = BlockingObservable.from(Observable.empty());
             assertEquals("default", observable.lastOrDefault("default"));
         }
 
@@ -460,7 +460,7 @@ public void testSingle() {
 
         @Test
         public void testSingleDefault() {
-            BlockingObservable<Object> observable = BlockingObservable.from(Observable.from());
+            BlockingObservable<Object> observable = BlockingObservable.from(Observable.empty());
             assertEquals("default", observable.singleOrDefault("default"));
         }