BtPromise: Adding a distinction between successful and failure.1.0

o Chain can now call fail() instead of stop() to signal failure.
o The finally handlers can be changed to get this info later.
o Should probably make all callbacks take the BtDevice as a callback instead of BluetoothGatt and make the gatt instance available through the device. This way state can be kept in the device's tag.
BtPromise: always discover services when operating inside a connection.

1 files changed, 45 insertions, 0 deletions

diff --git a/app/src/main/java/io/trygvis/android/Optional.java b/app/src/main/java/io/trygvis/android/Optional.java
new file mode 100644
index 0000000..616f9a7
--- /dev/null
+++ b/app/src/main/java/io/trygvis/android/Optional.java
@@ -0,0 +1,45 @@
+package io.trygvis.android;
+
+public final class Optional<T> {
+    private final T value;
+
+    public Optional(T value) {
+        this.value = value;
+    }
+
+    public T get() {
+        if (value == null) {
+            throw new IllegalStateException("get() on empty");
+        }
+
+        return value;
+    }
+
+    public boolean isPresent() {
+        return value != null;
+    }
+
+    public void ifPresent(Consumer<T> consumer) {
+        if (value == null) {
+            return;
+        }
+
+        consumer.accept(value);
+    }
+
+    public static <T> Optional<T> of(T t) {
+        if (t == null) {
+            throw new IllegalArgumentException("t can't be null");
+        }
+
+        return new Optional<>(t);
+    }
+
+    public static <T> Optional<T> empty() {
+        return new Optional<>(null);
+    }
+
+    public static <T> Optional<T> ofNullable(T t) {
+        return t != null ? of(t) : empty();
+    }
+}