Support reading of empty interfaces

3 files changed, 47 insertions, 8 deletions

diff --git a/src/main/java/org/zwobble/couscous/frontends/java/JavaReader.java b/src/main/java/org/zwobble/couscous/frontends/java/JavaReader.java
index 6e7f3fc..4eb7c7d 100644
--- a/src/main/java/org/zwobble/couscous/frontends/java/JavaReader.java
+++ b/src/main/java/org/zwobble/couscous/frontends/java/JavaReader.java
@@ -17,6 +17,7 @@ import java.nio.file.Path;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
+import java.util.Set;
 import java.util.function.Function;
 
 import static com.google.common.collect.Iterables.concat;
@@ -65,18 +66,24 @@ public class JavaReader {
         classes = ImmutableList.builder();
     }
 
-    private ClassNode readCompilationUnit(CompilationUnit ast) {
+    private TypeNode readCompilationUnit(CompilationUnit ast) {
         TypeName name = generateClassName(ast);
         Scope scope = Scope.create().enterClass(name);
         TypeDeclaration type = (TypeDeclaration)ast.types().get(0);
         TypeDeclarationBody body = readTypeDeclarationBody(scope, name, type.bodyDeclarations());
-        return ClassNode.declareClass(
-            name,
-            superTypes(type),
-            body.getFields(),
-            body.getStaticConstructor(),
-            body.getConstructor(),
-            body.getMethods());
+        Set<TypeName> superTypes = superTypes(type);
+        if (type.isInterface()) {
+            // TODO: throw exception if other parts of body are declared
+            return InterfaceNode.declareInterface(name, superTypes, body.getMethods());
+        } else {
+            return ClassNode.declareClass(
+                name,
+                superTypes,
+                body.getFields(),
+                body.getStaticConstructor(),
+                body.getConstructor(),
+                body.getMethods());
+        }
     }
 
     GeneratedClosure readExpressionMethodReference(Scope outerScope, ExpressionMethodReference expression) {
diff --git a/src/main/java/org/zwobble/couscous/util/ExtraSets.java b/src/main/java/org/zwobble/couscous/util/ExtraSets.java
new file mode 100644
index 0000000..ab3dd16
--- /dev/null
+++ b/src/main/java/org/zwobble/couscous/util/ExtraSets.java
@@ -0,0 +1,17 @@
+package org.zwobble.couscous.util;
+
+import com.google.common.collect.ImmutableSet;
+
+import java.util.Set;
+
+public class ExtraSets {
+    private ExtraSets() {}
+
+    public static <T> Set<T> set() {
+        return ImmutableSet.of();
+    }
+
+    public static <T> Set<T> set(T value1) {
+        return ImmutableSet.of(value1);
+    }
+}
diff --git a/src/test/java/org/zwobble/couscous/tests/frontends/java/JavaReaderTests.java b/src/test/java/org/zwobble/couscous/tests/frontends/java/JavaReaderTests.java
index dc5965a..e6a7a3e 100644
--- a/src/test/java/org/zwobble/couscous/tests/frontends/java/JavaReaderTests.java
+++ b/src/test/java/org/zwobble/couscous/tests/frontends/java/JavaReaderTests.java
@@ -8,7 +8,9 @@ import org.zwobble.couscous.values.StringValue;
 
 import java.util.List;
 
+import static org.hamcrest.Matchers.hasSize;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThat;
 import static org.zwobble.couscous.ast.AnnotationNode.annotation;
 import static org.zwobble.couscous.ast.AssignmentNode.assign;
 import static org.zwobble.couscous.ast.AssignmentNode.assignStatement;
@@ -27,6 +29,7 @@ import static org.zwobble.couscous.ast.VariableReferenceNode.reference;
 import static org.zwobble.couscous.ast.WhileNode.whileLoop;
 import static org.zwobble.couscous.tests.frontends.java.JavaReading.*;
 import static org.zwobble.couscous.util.ExtraLists.list;
+import static org.zwobble.couscous.util.ExtraSets.set;
 
 public class JavaReaderTests {
     @Test
@@ -296,4 +299,16 @@ public class JavaReaderTests {
             list(returns(boxInt(literal(1)))),
             method.getBody());
     }
+
+    @Test
+    public void canReadEmptyInterface() {
+        String source = "package com.example;" +
+            "public interface Example {}";
+        List<TypeNode> classes = readSource("com/example/Example.java", source);
+        assertThat(classes, hasSize(1));
+        InterfaceNode classNode = (InterfaceNode) classes.get(0);
+        assertEquals(TypeName.of("com.example.Example"), classNode.getName());
+        assertEquals(list(), classNode.getMethods());
+        assertEquals(set(ObjectValues.OBJECT), classNode.getSuperTypes());
+    }
 }