Look for default layout in parents if not specified

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

@@ -15,6 +15,7 @@
 
 import java.io.IOException;
 import java.lang.annotation.Annotation;
+import java.lang.annotation.AnnotationTypeMismatchException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashSet;
@@ -493,7 +494,7 @@ private void addDefaultLayoutMethodIfNeeded(TypeElement originalClassElement,
       return;
     }
 
-    EpoxyModelClass annotation = originalClassElement.getAnnotation(EpoxyModelClass.class);
+    EpoxyModelClass annotation = findClassAnnotationWithLayout(originalClassElement);
     if (annotation == null) {
       throwError("Model must use %s annotation if it does not implement %s. (class: %s)",
           EpoxyModelClass.class,
@@ -516,6 +517,41 @@ private void addDefaultLayoutMethodIfNeeded(TypeElement originalClassElement,
     methods.add(getDefaultLayoutMethod);
   }
 
+  /**
+   * Looks for {@link EpoxyModelClass} annotation in the original class and his parents.
+   */
+  private EpoxyModelClass findClassAnnotationWithLayout(TypeElement classElement)
+      throws EpoxyProcessorException {
+    if (!isEpoxyModel(classElement)) {
+      return null;
+    }
+
+    EpoxyModelClass annotation = classElement.getAnnotation(EpoxyModelClass.class);
+    if (annotation == null) {
+      return null;
+    }
+
+    try {
+      int layoutRes = annotation.layout();
+      if (layoutRes != 0) {
+        return annotation;
+      }
+    } catch (AnnotationTypeMismatchException e) {
+      throwError("Invalid layout value in %s annotation. (class: %s). %s: %s",
+          EpoxyModelClass.class,
+          classElement.getSimpleName(),
+          e.getClass().getSimpleName(),
+          e.getMessage());
+      return null;
+    }
+
+    TypeElement superclassElement = (TypeElement) typeUtils.asElement(classElement.getSuperclass());
+    EpoxyModelClass annotationOnSuperClass = findClassAnnotationWithLayout(superclassElement);
+
+    // Return the last annotation value we have so the proper error can be thrown if needed
+    return annotationOnSuperClass != null ? annotationOnSuperClass : annotation;
+  }
+
   private void generateParams(StringBuilder statementBuilder, List<ParameterSpec> params) {
     boolean first = true;
     for (ParameterSpec param : params) {

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

@@ -27,6 +27,10 @@ static boolean isEpoxyModel(TypeMirror type) {
     return isSubtypeOfType(type, EPOXY_MODEL_TYPE);
   }
 
+  static boolean isEpoxyModel(TypeElement type) {
+    return isEpoxyModel(type.asType());
+  }
+
   static boolean isEpoxyModelWithHolder(TypeElement type) {
     return isSubtypeOfType(type.asType(), EPOXY_MODEL_HOLDER_TYPE);
   }

epoxy-processortest/src/test/java/com/airbnb/epoxy/EpoxyProcessorTest.java

@@ -404,4 +404,68 @@ public void testGenerateDefaultLayoutMethod() {
         .and()
         .generatesSources(generatedModel);
   }
+
+  @Test
+  public void testGenerateDefaultLayoutMethodFailsIfLayoutNotSpecified() {
+    JavaFileObject model = JavaFileObjects
+        .forResource("GenerateDefaultLayoutMethodNoLayout.java");
+
+    assert_().about(javaSource())
+        .that(model)
+        .processedWith(new EpoxyProcessor())
+        .failsToCompile()
+        .withErrorContaining("Model must specify a valid layout resource");
+  }
+
+  @Test
+  public void testGeneratedDefaultMethodWithLayoutSpecifiedInParent() {
+    JavaFileObject model = JavaFileObjects
+        .forResource("GenerateDefaultLayoutMethodParentLayout.java");
+
+    JavaFileObject generatedNoLayoutModel = JavaFileObjects
+        .forResource("GenerateDefaultLayoutMethodParentLayout$NoLayout_.java");
+    JavaFileObject generatedWithLayoutModel =
+        JavaFileObjects.forResource("GenerateDefaultLayoutMethodParentLayout$WithLayout_.java");
+
+    assert_().about(javaSource())
+        .that(model)
+        .processedWith(new EpoxyProcessor())
+        .compilesWithoutError()
+        .and()
+        .generatesSources(generatedNoLayoutModel, generatedWithLayoutModel);
+
+  }
+
+  @Test
+  public void testGeneratedDefaultMethodWithLayoutSpecifiedInNextParent() {
+    JavaFileObject model = JavaFileObjects
+        .forResource("GenerateDefaultLayoutMethodNextParentLayout.java");
+
+    JavaFileObject generatedNoLayoutModel = JavaFileObjects
+        .forResource("GenerateDefaultLayoutMethodNextParentLayout$NoLayout.java");
+    JavaFileObject generatedStillNoLayoutModel = JavaFileObjects
+        .forResource("GenerateDefaultLayoutMethodNextParentLayout$StillNoLayout.java");
+    JavaFileObject generatedWithLayoutModel =
+        JavaFileObjects.forResource("GenerateDefaultLayoutMethodNextParentLayout$WithLayout.java");
+
+    assert_().about(javaSource())
+        .that(model)
+        .processedWith(new EpoxyProcessor())
+        .compilesWithoutError()
+        .and()
+        .generatesSources(generatedNoLayoutModel, generatedStillNoLayoutModel,
+            generatedWithLayoutModel);
+  }
+
+  @Test
+  public void testGeneratedDefaultMethodWithLayoutFailsIfNotSpecifiedInParent() {
+    JavaFileObject model = JavaFileObjects
+        .forResource("GenerateDefaultLayoutMethodParentStillNoLayout.java");
+
+    assert_().about(javaSource())
+        .that(model)
+        .processedWith(new EpoxyProcessor())
+        .failsToCompile()
+        .withErrorContaining("Model must specify a valid layout resource");
+  }
 }

epoxy-processortest/src/test/resources/GenerateDefaultLayoutMethodNextParentLayout$NoLayout.java

@@ -0,0 +1,111 @@
+package com.airbnb.epoxy;
+
+import android.support.annotation.LayoutRes;
+import java.lang.CharSequence;
+import java.lang.Object;
+import java.lang.Override;
+import java.lang.String;
+
+/**
+ * Generated file. Do not modify! */
+public class GenerateDefaultLayoutMethodNextParentLayout$NoLayout_ extends GenerateDefaultLayoutMethodNextParentLayout.NoLayout {
+  public GenerateDefaultLayoutMethodNextParentLayout$NoLayout_() {
+    super();
+  }
+
+  public GenerateDefaultLayoutMethodNextParentLayout$NoLayout_ value(int value) {
+    this.value = value;
+    return this;
+  }
+
+  public int value() {
+    return value;
+  }
+
+  @Override
+  public GenerateDefaultLayoutMethodNextParentLayout$NoLayout_ id(long id) {
+    super.id(id);
+    return this;
+  }
+
+  @Override
+  public GenerateDefaultLayoutMethodNextParentLayout$NoLayout_ id(CharSequence key) {
+    super.id(key);
+    return this;
+  }
+
+  @Override
+  public GenerateDefaultLayoutMethodNextParentLayout$NoLayout_ id(CharSequence key, long id) {
+    super.id(key, id);
+    return this;
+  }
+
+  @Override
+  public GenerateDefaultLayoutMethodNextParentLayout$NoLayout_ layout(@LayoutRes int arg0) {
+    super.layout(arg0);
+    return this;
+  }
+
+  @Override
+  public GenerateDefaultLayoutMethodNextParentLayout$NoLayout_ show() {
+    super.show();
+    return this;
+  }
+
+  @Override
+  public GenerateDefaultLayoutMethodNextParentLayout$NoLayout_ show(boolean show) {
+    super.show(show);
+    return this;
+  }
+
+  @Override
+  public GenerateDefaultLayoutMethodNextParentLayout$NoLayout_ hide() {
+    super.hide();
+    return this;
+  }
+
+  @Override
+  @LayoutRes
+  protected int getDefaultLayout() {
+    return 1;
+  }
+
+  @Override
+  public GenerateDefaultLayoutMethodNextParentLayout$NoLayout_ reset() {
+    this.value = 0;
+    super.reset();
+    return this;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof GenerateDefaultLayoutMethodNextParentLayout$NoLayout_)) {
+      return false;
+    }
+    if (!super.equals(o)) {
+      return false;
+    }
+    GenerateDefaultLayoutMethodNextParentLayout$NoLayout_ that = (GenerateDefaultLayoutMethodNextParentLayout$NoLayout_) o;
+    if (value != that.value) {
+      return false;
+    }
+    return true;
+  }
+
+  @Override
+  public int hashCode() {
+    int result = super.hashCode();
+    result = 31 * result + value;
+    return result;
+  }
+
+  @Override
+  public String toString() {
+    return "GenerateDefaultLayoutMethodNextParentLayout$NoLayout_{" +
+        "value=" + value +
+        "}" + super.toString();
+  }
+}

epoxy-processortest/src/test/resources/GenerateDefaultLayoutMethodNextParentLayout$StillNoLayout.java

@@ -0,0 +1,96 @@
+package com.airbnb.epoxy;
+
+import android.support.annotation.LayoutRes;
+import java.lang.CharSequence;
+import java.lang.Object;
+import java.lang.Override;
+import java.lang.String;
+
+/**
+ * Generated file. Do not modify! */
+public class GenerateDefaultLayoutMethodNextParentLayout$StillNoLayout_ extends GenerateDefaultLayoutMethodNextParentLayout.StillNoLayout {
+  public GenerateDefaultLayoutMethodNextParentLayout$StillNoLayout_() {
+    super();
+  }
+
+  @Override
+  public GenerateDefaultLayoutMethodNextParentLayout$StillNoLayout_ id(long id) {
+    super.id(id);
+    return this;
+  }
+
+  @Override
+  public GenerateDefaultLayoutMethodNextParentLayout$StillNoLayout_ id(CharSequence key) {
+    super.id(key);
+    return this;
+  }
+
+  @Override
+  public GenerateDefaultLayoutMethodNextParentLayout$StillNoLayout_ id(CharSequence key, long id) {
+    super.id(key, id);
+    return this;
+  }
+
+  @Override
+  public GenerateDefaultLayoutMethodNextParentLayout$StillNoLayout_ layout(@LayoutRes int arg0) {
+    super.layout(arg0);
+    return this;
+  }
+
+  @Override
+  public GenerateDefaultLayoutMethodNextParentLayout$StillNoLayout_ show() {
+    super.show();
+    return this;
+  }
+
+  @Override
+  public GenerateDefaultLayoutMethodNextParentLayout$StillNoLayout_ show(boolean show) {
+    super.show(show);
+    return this;
+  }
+
+  @Override
+  public GenerateDefaultLayoutMethodNextParentLayout$StillNoLayout_ hide() {
+    super.hide();
+    return this;
+  }
+
+  @Override
+  @LayoutRes
+  protected int getDefaultLayout() {
+    return 1;
+  }
+
+  @Override
+  public GenerateDefaultLayoutMethodNextParentLayout$StillNoLayout_ reset() {
+    super.reset();
+    return this;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof GenerateDefaultLayoutMethodNextParentLayout$StillNoLayout_)) {
+      return false;
+    }
+    if (!super.equals(o)) {
+      return false;
+    }
+    GenerateDefaultLayoutMethodNextParentLayout$StillNoLayout_ that = (GenerateDefaultLayoutMethodNextParentLayout$StillNoLayout_) o;
+    return true;
+  }
+
+  @Override
+  public int hashCode() {
+    int result = super.hashCode();
+    return result;
+  }
+
+  @Override
+  public String toString() {
+    return "GenerateDefaultLayoutMethodNextParentLayout$StillNoLayout_{" +
+        "}" + super.toString();
+  }
+}