Extract interface out of JavaField

compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/structure/JavaElementCollectionFromPsiArrayUtil.java

@@ -64,7 +64,7 @@ public class JavaElementCollectionFromPsiArrayUtil {
         if (fields.length == 0) return Collections.emptyList();
         List<JavaField> result = new ArrayList<JavaField>(fields.length);
         for (PsiField psiField : fields) {
-            result.add(new JavaField(psiField));
+            result.add(new JavaFieldImpl(psiField));
         }
         return result;
     }

compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/structure/JavaField.java

@@ -16,27 +16,16 @@
 
 package org.jetbrains.jet.lang.resolve.java.structure;
 
-import com.intellij.psi.PsiEnumConstant;
 import com.intellij.psi.PsiField;
 import org.jetbrains.annotations.NotNull;
 
-public class JavaField extends JavaMemberImpl {
-    public JavaField(@NotNull PsiField psiField) {
-        super(psiField);
-    }
-
+public interface JavaField extends JavaMember {
     @NotNull
     @Override
-    public PsiField getPsi() {
-        return (PsiField) super.getPsi();
-    }
+    PsiField getPsi();
 
-    public boolean isEnumEntry() {
-        return getPsi() instanceof PsiEnumConstant;
-    }
+    boolean isEnumEntry();
 
     @NotNull
-    public JavaType getType() {
-        return JavaType.create(getPsi().getType());
-    }
+    JavaType getType();
 }

compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/structure/JavaFieldImpl.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2010-2013 JetBrains s.r.o.
+ *
+ * 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 org.jetbrains.jet.lang.resolve.java.structure;
+
+import com.intellij.psi.PsiEnumConstant;
+import com.intellij.psi.PsiField;
+import org.jetbrains.annotations.NotNull;
+
+public class JavaFieldImpl extends JavaMemberImpl implements JavaField {
+    public JavaFieldImpl(@NotNull PsiField psiField) {
+        super(psiField);
+    }
+
+    @NotNull
+    @Override
+    public PsiField getPsi() {
+        return (PsiField) super.getPsi();
+    }
+
+    @Override
+    public boolean isEnumEntry() {
+        return getPsi() instanceof PsiEnumConstant;
+    }
+
+    @Override
+    @NotNull
+    public JavaType getType() {
+        return JavaType.create(getPsi().getType());
+    }
+}

compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/structure/JavaReferenceAnnotationArgument.java

@@ -40,7 +40,7 @@ public class JavaReferenceAnnotationArgument extends JavaAnnotationArgument {
         PsiReferenceExpression expression = getPsi();
         PsiElement element = expression.resolve();
         if (element instanceof PsiEnumConstant) {
-            return new JavaField((PsiField) element);
+            return new JavaFieldImpl((PsiField) element);
         }
         // TODO: other types of references
         return null;