Add support for JsonAlias annotation

Author: alicederyn

gradle.properties

@@ -4,7 +4,7 @@ guava=com.google.guava:guava:16.0
 guavaTestlib=com.google.guava:guava-testlib:17.0
 gwtUser=com.google.gwt:gwt-user:2.8.0
 hamcrest=org.hamcrest:hamcrest-all:1.3
-jacksonVersion=2.6.1
+jacksonVersion=2.9.3
 javassist=org.javassist:javassist:3.19.0-GA
 jsr305=com.google.code.findbugs:jsr305:3.0.0
 junit=junit:junit:4.12

src/main/java/org/inferred/freebuilder/processor/JacksonSupport.java

@@ -31,6 +31,8 @@ private enum GenerateAnnotation {
       QualifiedName.of("com.fasterxml.jackson.annotation", "JsonProperty");
   private static final String JACKSON_XML_ANNOTATION_PACKAGE =
       "com.fasterxml.jackson.dataformat.xml.annotation";
+  private static final String JSON_ALIAS =
+      "com.fasterxml.jackson.annotation.JsonAlias";
   private static final QualifiedName JSON_ANY_GETTER =
       QualifiedName.of("com.fasterxml.jackson.annotation", "JsonAnyGetter");
   private static final QualifiedName JSON_ANY_SETTER =
@@ -78,15 +80,18 @@ public void addJacksonAnnotations(
     getterMethod
         .getAnnotationMirrors()
         .stream()
-        .filter(this::isXmlAnnotation)
+        .filter(this::shouldCopyAnnotation)
         .forEach(annotation -> {
           resultBuilder.addAccessorAnnotations(Excerpts.add("%s%n", annotation));
         });
   }
 
-  private boolean isXmlAnnotation(AnnotationMirror mirror) {
-    Name pkg = elements.getPackageOf(mirror.getAnnotationType().asElement()).getQualifiedName();
-    return pkg.contentEquals(JACKSON_XML_ANNOTATION_PACKAGE);
+  private boolean shouldCopyAnnotation(AnnotationMirror mirror) {
+    TypeElement annotationTypeElement = (TypeElement) mirror.getAnnotationType().asElement();
+    Name qualifiedName = annotationTypeElement.getQualifiedName();
+    Name pkg = elements.getPackageOf(annotationTypeElement).getQualifiedName();
+    return pkg.contentEquals(JACKSON_XML_ANNOTATION_PACKAGE)
+        || qualifiedName.contentEquals(JSON_ALIAS);
   }
 
   private static GenerateAnnotation generateDefaultAnnotations(ExecutableElement getterMethod) {

src/test/java/org/inferred/freebuilder/processor/JacksonIntegrationTest.java

@@ -0,0 +1,54 @@
+package org.inferred.freebuilder.processor;
+
+import com.fasterxml.jackson.annotation.JsonAlias;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
+
+import org.inferred.freebuilder.FreeBuilder;
+import org.inferred.freebuilder.processor.source.SourceBuilder;
+import org.inferred.freebuilder.processor.source.feature.FeatureSet;
+import org.inferred.freebuilder.processor.source.feature.StaticFeatureSet;
+import org.inferred.freebuilder.processor.source.testing.BehaviorTester;
+import org.inferred.freebuilder.processor.source.testing.ParameterizedBehaviorTestFactory.Shared;
+import org.inferred.freebuilder.processor.source.testing.TestBuilder;
+import org.junit.Test;
+
+public class JacksonIntegrationTest {
+
+  @Shared public BehaviorTester behaviorTester;
+
+  @Test
+  public void testJsonAliasSupport() {
+    FeatureSet featureSet = new StaticFeatureSet();
+    BehaviorTester.create(featureSet)
+        .with(new Processor(featureSet))
+        .with(SourceBuilder.forTesting()
+            .addLine("package com.example;")
+            .addLine("@%s", FreeBuilder.class)
+            .addLine("@%s(builder = DataType.Builder.class)", JsonDeserialize.class)
+            .addLine("public abstract class DataType {")
+            .addLine("  @%s({\"a\", \"theagame\"})", JsonAlias.class)
+            .addLine("  public abstract int propertyA();")
+            .addLine("")
+            .addLine("  public static class Builder extends DataType_Builder {}")
+            .addLine("}"))
+        .with(testBuilder()
+            .addLine("DataType expected = new DataType.Builder().propertyA(13).build();")
+            .addLine("%1$s mapper = new %1$s();", ObjectMapper.class)
+            .addLine("String canonicalJson = \"{ \\\"propertyA\\\": 13 }\";")
+            .addLine("DataType canonical = mapper.readValue(canonicalJson, DataType.class);")
+            .addLine("assertEquals(expected, canonical);")
+            .addLine("String alternative1Json = \"{ \\\"a\\\": 13 }\";")
+            .addLine("DataType alternative1 = mapper.readValue(canonicalJson, DataType.class);")
+            .addLine("assertEquals(expected, alternative1);")
+            .addLine("String alternative2Json = \"{ \\\"theagame\\\": 13 }\";")
+            .addLine("DataType alternative2 = mapper.readValue(canonicalJson, DataType.class);")
+            .addLine("assertEquals(expected, alternative2);")
+            .build())
+        .runTest();
+  }
+
+  private static TestBuilder testBuilder() {
+    return new TestBuilder().addImport("com.example.DataType");
+  }
+}

src/test/java/org/inferred/freebuilder/processor/JacksonSupportTest.java

@@ -18,6 +18,7 @@
 import static com.google.common.collect.Iterables.getOnlyElement;
 import static com.google.common.truth.Truth.assertThat;
 
+import com.fasterxml.jackson.annotation.JsonAlias;
 import com.fasterxml.jackson.annotation.JsonAnyGetter;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
@@ -145,6 +146,21 @@ public void jsonAnyGetterAnnotationDisablesImplicitProperty() throws CannotGener
     assertThat(property.getAccessorAnnotations()).named("property accessor annotations").isEmpty();
   }
 
+  @Test
+  public void jsonAliasAnnotationCopied() throws CannotGenerateCodeException {
+    GeneratedBuilder builder = (GeneratedBuilder) analyser.analyse(model.newType(
+        "package com.example;",
+        "@" + JsonDeserialize.class.getName() + "(builder = DataType.Builder.class)",
+        "public interface DataType {",
+        "  @" + JsonAlias.class.getName() + "({\"foo\", \"bar\"}) int getFooBar();",
+        "  class Builder extends DataType_Builder {}",
+        "}"));
+
+    Property property = getOnlyElement(builder.getGeneratorsByProperty().keySet());
+    assertPropertyHasAnnotation(property, JsonProperty.class, "@JsonProperty(\"fooBar\")");
+    assertPropertyHasAnnotation(property, JsonAlias.class, "@JsonAlias({\"foo\", \"bar\"})");
+  }
+
   private static void assertPropertyHasAnnotation(
       Property property, Class<? extends Annotation> annotationClass, String annotationString) {
     Excerpt annotationExcerpt = property.getAccessorAnnotations()