Databinding naming pattern support (#319)

* Easier way to add databinding layouts

* Layout pattern option

epoxy-annotations/src/main/java/com/airbnb/epoxy/EpoxyDataBindingLayouts.java

@@ -14,6 +14,9 @@
  * <p>
  * The layouts must not specify a custom databinding class name or package via the
  * class="com.example.CustomClassName" override in the layout xml.
+ * <p>
+ * Alternatively you can use {@link EpoxyDataBindingPattern} to avoid explicitly declaring each
+ * layout.
  */
 @Target(ElementType.PACKAGE)
 @Retention(RetentionPolicy.CLASS)

epoxy-annotations/src/main/java/com/airbnb/epoxy/EpoxyDataBindingPattern.java

@@ -0,0 +1,32 @@
+package com.airbnb.epoxy;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Used to specify a naming pattern for the databinding layouts that you want models generated for.
+ * Use this instead of {@link EpoxyDataBindingLayouts} to avoid having to explicitly list every
+ * databinding layout.
+ * <p>
+ * The layouts must not specify a custom databinding class name or package via the
+ * class="com.example.CustomClassName" override in the layout xml.
+ */
+@Target(ElementType.PACKAGE)
+@Retention(RetentionPolicy.CLASS)
+public @interface EpoxyDataBindingPattern {
+  /**
+   * The R class used in this module (eg "com.example.app.R.class"). This is needed so Epoxy can
+   * look up layout files.
+   */
+  Class<?> rClass();
+  /**
+   * A string prefix that your databinding layouts start with. Epoxy will generate a model for each
+   * databinding layout whose name starts with this.
+   * <p>
+   * For example, if you set this prefix to "view_holder" and you have a "view_holder_header.xml"
+   * databinding layout, Epoxy will generate a HeaderBindingModel_ class for that layout.
+   */
+  String layoutPrefix();
+}

epoxy-integrationtest/src/main/java/com/airbnb/epoxy/integrationtest/package-info.java

@@ -1,4 +1,6 @@
+@EpoxyDataBindingPattern(rClass = R.class, layoutPrefix = "view_holder")
 @EpoxyDataBindingLayouts({R.layout.model_with_data_binding})
 package com.airbnb.epoxy.integrationtest;
 
 import com.airbnb.epoxy.EpoxyDataBindingLayouts;
+import com.airbnb.epoxy.EpoxyDataBindingPattern;

epoxy-integrationtest/src/main/res/layout/view_holder_databinding_test.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <data>
+
+        <variable
+            name="stringValue"
+            type="String" />
+
+        <variable
+            name="clickListener"
+            type="android.view.View.OnClickListener" />
+    </data>
+
+    <Button
+        android:id="@+id/button"
+        android:layout_width="match_parent"
+        android:layout_height="40dp"
+        android:text="@{stringValue}" />
+
+</layout>

epoxy-integrationtest/src/main/res/layout/view_holder_no_databinding.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <!-- This layout does nothing, but it tests that the databinding processor skips none databinding layouts that match the naming pattern. -->
+
+</LinearLayout>

epoxy-integrationtest/src/test/java/com/airbnb/epoxy/DataBindingModelIntegrationTest.java

@@ -7,14 +7,14 @@
 
 import com.airbnb.epoxy.DataBindingEpoxyModel.DataBindingHolder;
 import com.airbnb.epoxy.integrationtest.BuildConfig;
+import com.airbnb.epoxy.integrationtest.DatabindingTestBindingModel_;
 import com.airbnb.epoxy.integrationtest.ModelWithDataBindingBindingModel_;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.robolectric.RobolectricTestRunner;
 import org.robolectric.annotation.Config;
 
-
 import java.util.Collections;
 import java.util.List;
 
@@ -144,4 +144,10 @@ public void typesWithHashCodeAreDiffed() {
     verify(observerMock).onItemRangeChanged(eq(0), eq(1), any());
     verifyNoMoreInteractions(observerMock);
   }
+
+  @Test
+  public void generatesBindingModelFromNamingPattern() {
+    // Make sure that the model was generated from the annotation naming pattern
+    new DatabindingTestBindingModel_();
+  }
 }

epoxy-processor/src/main/java/com/airbnb/epoxy/ClassNames.java

@@ -41,6 +41,7 @@ private ClassNames() {
   static final ClassName EPOXY_STRING_ATTRIBUTE_DATA = get(PKG_EPOXY, "StringAttributeData");
   static final ClassName EPOXY_CONTROLLER = get(PKG_EPOXY, "EpoxyController");
   static final ClassName EPOXY_STYLE_BUILDER_CALLBACK = get(PKG_EPOXY, "StyleBuilderCallback");
+  static final ClassName EPOXY_CONTROLLER_HELPER = get(PKG_EPOXY, "ControllerHelper");
 
   static final ClassName PARIS_STYLE_UTILS = get(PKG_PARIS, "StyleApplierUtils", "Companion");
   static final ClassName PARIS_STYLE = get(PKG_PARIS, "Style");

epoxy-processor/src/main/java/com/airbnb/epoxy/ConfigManager.java

@@ -109,17 +109,16 @@ List<Exception> processConfigurations(RoundEnvironment roundEnv) {
         continue;
       }
 
-      TypeMirror rClassType =
-          getClassParamFromAnnotation(element, PackageModelViewConfig.class, "rClass");
-      if (rClassType == null) {
+      ClassName rClassName =
+          getClassParamFromAnnotation(element, PackageModelViewConfig.class, "rClass", typeUtils);
+
+      if (rClassName == null) {
         errors.add(buildEpoxyException(
             "Unable to get R class details from annotation %s (package: %s)",
             PackageModelViewConfig.class.getSimpleName(), packageName));
         continue;
       }
 
-      ClassName rClassName =
-          ClassName.get((TypeElement) typeUtils.asElement(rClassType));
 
       String rLayoutClassString = rClassName.reflectionName();
       if (!rLayoutClassString.endsWith(".R")

epoxy-processor/src/main/java/com/airbnb/epoxy/ControllerProcessor.java

@@ -1,6 +1,5 @@
 package com.airbnb.epoxy;
 
-import com.squareup.javapoet.ClassName;
 import com.squareup.javapoet.FieldSpec;
 import com.squareup.javapoet.JavaFile;
 import com.squareup.javapoet.MethodSpec;
@@ -39,7 +38,6 @@
 import static com.airbnb.epoxy.Utils.validateFieldAccessibleViaGeneratedCode;
 
 class ControllerProcessor {
-  private static final String CONTROLLER_HELPER_INTERFACE = "com.airbnb.epoxy.ControllerHelper";
   private Filer filer;
   private Elements elementUtils;
   private Types typeUtils;
@@ -237,9 +235,9 @@ private void generateJava(Map<TypeElement, ControllerClassInfo> controllerClassM
 
   private void generateHelperClassForController(ControllerClassInfo controllerInfo)
       throws IOException {
-    ClassName superclass = ClassName.get(elementUtils.getTypeElement(CONTROLLER_HELPER_INTERFACE));
     ParameterizedTypeName parameterizeSuperClass =
-        ParameterizedTypeName.get(superclass, controllerInfo.getControllerClassType());
+        ParameterizedTypeName
+            .get(ClassNames.EPOXY_CONTROLLER_HELPER, controllerInfo.getControllerClassType());
 
     TypeSpec.Builder builder = TypeSpec.classBuilder(controllerInfo.getGeneratedClassName())
         .addJavadoc("Generated file. Do not modify!")

epoxy-processor/src/main/java/com/airbnb/epoxy/DataBindingModelInfo.kt

@@ -0,0 +1,77 @@
+package com.airbnb.epoxy
+
+import com.airbnb.epoxy.ClassNames.*
+import com.airbnb.epoxy.Utils.*
+import com.squareup.javapoet.*
+import javax.lang.model.element.*
+import javax.lang.model.util.*
+
+internal class DataBindingModelInfo(
+        private val typeUtils: Types,
+        private val elementUtils: Elements,
+        val layoutResource: ResourceValue,
+        private val moduleName: String,
+        private val layoutPrefix: String = ""
+) : GeneratedModelInfo() {
+    private val dataBindingClassName: ClassName
+
+    val dataBindingClassElement: Element?
+        get() = getElementByName(dataBindingClassName, elementUtils, typeUtils)
+
+    init {
+
+        dataBindingClassName = getDataBindingClassNameForResource(layoutResource, moduleName)
+
+        superClassElement = Utils.getElementByName(EPOXY_DATA_BINDING_MODEL,
+                                                   elementUtils, typeUtils) as TypeElement
+        superClassName = EPOXY_DATA_BINDING_MODEL
+        generatedClassName = buildGeneratedModelName()
+        parametrizedClassName = generatedClassName
+        boundObjectTypeName = EPOXY_DATA_BINDING_HOLDER
+        shouldGenerateModel = true
+
+        collectMethodsReturningClassType(superClassElement, typeUtils)
+    }
+
+    /**
+     * Look up the DataBinding class generated for this model's layout file and parse the attributes
+     * for it.
+     */
+    fun parseDataBindingClass() {
+        // This databinding class won't exist until the second round of annotation processing since
+        // it is generated in the first round.
+
+        val hashCodeValidator = HashCodeValidator(typeUtils, elementUtils)
+        dataBindingClassElement!!.enclosedElements
+                .filter { Utils.isSetterMethod(it) }
+                .forEach {
+                    addAttribute(
+                            DataBindingAttributeInfo(this, it as ExecutableElement,
+                                                     hashCodeValidator))
+                }
+    }
+
+    private fun getDataBindingClassNameForResource(
+            layoutResource: ResourceValue,
+            moduleName: String
+    ): ClassName {
+        val modelName = layoutResource.resourceName!!.toUpperCamelCase().plus(BINDING_SUFFIX)
+
+        return ClassName.get(moduleName + ".databinding", modelName)
+    }
+
+    private fun buildGeneratedModelName(): ClassName {
+        val modelName = layoutResource.resourceName!!
+                .removePrefix(layoutPrefix)
+                .toUpperCamelCase()
+                .plus(BINDING_SUFFIX)
+                .plus(GeneratedModelInfo.GENERATED_MODEL_SUFFIX)
+
+        return ClassName.get(moduleName, modelName)
+    }
+
+    companion object {
+
+        val BINDING_SUFFIX = "Binding"
+    }
+}