Add Inspector annotations

Add the @InspectableChildren, @InspectableNodeName, and
@InspectableProperty annotations, and a host library containing them for
use in the annotation processor.

Bug: 118893821
Test: m
Change-Id: I11dcec09c2c69db951fc87d37463b6f8ca28d8fe
diff --git a/Android.bp b/Android.bp
index 8163ff8..a63e090 100644
--- a/Android.bp
+++ b/Android.bp
@@ -764,6 +764,16 @@
     ],
 }
 
+// A host library containing the inspector annotations for inspector-annotation-processor.
+java_library_host {
+    name: "inspector-annotation",
+    srcs: [
+        "core/java/android/view/inspector/InspectableChildren.java",
+        "core/java/android/view/inspector/InspectableNodeName.java",
+        "core/java/android/view/inspector/InspectableProperty.java",
+    ],
+}
+
 // A host library including just UnsupportedAppUsage.java so that the annotation
 // processor can also use this annotation.
 java_library_host {
diff --git a/core/java/android/view/inspector/InspectableChildren.java b/core/java/android/view/inspector/InspectableChildren.java
new file mode 100644
index 0000000..de8fa29
--- /dev/null
+++ b/core/java/android/view/inspector/InspectableChildren.java
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.view.inspector;
+
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.RetentionPolicy.SOURCE;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+/**
+ * Marks a getter for an inspectable node's inspectable children.
+ *
+ * This annotation can be applied to any getter that returns a collection of objects, either an
+ * array, an {@link Iterable} or a {@link java.util.Iterator}. The getter may return null, which
+ * will be treated as an empty collection. Additionally, the inspector will discard any null
+ * entries in the collection.
+ *
+ * By default, this annotation is inherited. At runtime, the inspector introspects on the class
+ * hierachy and uses the annotated getter from the bottommost class, if different from any
+ * annoated getters of the parent class. If a class inherits from a parent class with an annotated
+ * getter, but does not include this annotation, the child class will be traversed using the
+ * getter annotated on the parent. This holds true even if the child class overrides the getter.
+ *
+ * @see InspectionHelper#traverseChildren(Object, ChildTraverser)
+ * @see InspectionHelper#hasChildTraversal()
+ * @hide
+ */
+@Target({METHOD})
+@Retention(SOURCE)
+public @interface InspectableChildren {
+}
diff --git a/core/java/android/view/inspector/InspectableNodeName.java b/core/java/android/view/inspector/InspectableNodeName.java
new file mode 100644
index 0000000..716409c
--- /dev/null
+++ b/core/java/android/view/inspector/InspectableNodeName.java
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.view.inspector;
+
+import static java.lang.annotation.ElementType.TYPE;
+import static java.lang.annotation.RetentionPolicy.SOURCE;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+/**
+ * Marks the node name to display to a developer in the inspection tree.
+ *
+ * This annotation is optional to marking a class as inspectable. If it is omitted, the node name
+ * will be inferred using the semantics of {@link Class#getSimpleName()}. The fully qualified class
+ * name is always available in the tree, this is for display purposes only. If a class is inflated
+ * from XML and the tag it inflates from does not match its simple name, this annotation should be
+ * used to inform the inspector to display the XML tag name in the inspection tree view.
+ *
+ * This annotation does not inherit. If a class extends an annotated parent class, but does not
+ * annotate itself, its node name will be inferred from its Java name.
+ *
+ * @see InspectionHelper#getNodeName()
+ * @hide
+ */
+@Target({TYPE})
+@Retention(SOURCE)
+public @interface InspectableNodeName {
+    /**
+     * The display name for nodes of this type.
+     *
+     * @return The name for nodes of this type
+     */
+    String value();
+}
diff --git a/core/java/android/view/inspector/InspectableProperty.java b/core/java/android/view/inspector/InspectableProperty.java
new file mode 100644
index 0000000..b0fd503
--- /dev/null
+++ b/core/java/android/view/inspector/InspectableProperty.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.view.inspector;
+
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.RetentionPolicy.SOURCE;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+/**
+ * Marks a getter of a property on an inspectable node.
+ *
+ * This annotation is inherited by default. If a child class doesn't add it to a getter, but a
+ * parent class does, the property will be inspected, even if the child overrides the definition
+ * of the getter. If a child class defines a property of the same name of a property on the parent
+ * but on a different getter, the inspector will use the child's getter when inspecting instances
+ * of the child, and the parent's otherwise.
+ *
+ * @see InspectionHelper#mapProperties(PropertyMapper)
+ * @see InspectionHelper#readProperties(Object, PropertyReader)
+ * @hide
+ */
+@Target({METHOD})
+@Retention(SOURCE)
+public @interface InspectableProperty {
+    /**
+     * The name of the property.
+     *
+     * If left empty (the default), the property name will be inferred from the name of the getter
+     * method.
+     *
+     * @return The name of the property.
+     */
+    String value() default "";
+}