Extract interface out of JavaPackage

compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/JavaClassFinderImpl.java

@@ -22,6 +22,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.lang.resolve.java.structure.JavaClass;
 import org.jetbrains.jet.lang.resolve.java.structure.JavaPackage;
+import org.jetbrains.jet.lang.resolve.java.structure.JavaPackageImpl;
 import org.jetbrains.jet.lang.resolve.name.FqName;
 
 import javax.inject.Inject;
@@ -45,6 +46,6 @@ public class JavaClassFinderImpl implements JavaClassFinder {
     @Override
     public JavaPackage findPackage(@NotNull FqName fqName) {
         PsiPackage psiPackage = psiClassFinder.findPsiPackage(fqName);
-        return psiPackage == null ? null : new JavaPackage(psiPackage);
+        return psiPackage == null ? null : new JavaPackageImpl(psiPackage);
     }
 }

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

@@ -44,7 +44,7 @@ public class JavaElementCollectionFromPsiArrayUtil {
         if (packages.length == 0) return Collections.emptyList();
         List<JavaPackage> result = new ArrayList<JavaPackage>(packages.length);
         for (PsiPackage psiPackage : packages) {
-            result.add(new JavaPackage(psiPackage));
+            result.add(new JavaPackageImpl(psiPackage));
         }
         return result;
     }

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

@@ -22,32 +22,17 @@ import org.jetbrains.jet.lang.resolve.name.FqName;
 
 import java.util.Collection;
 
-import static org.jetbrains.jet.lang.resolve.java.structure.JavaElementCollectionFromPsiArrayUtil.classes;
-import static org.jetbrains.jet.lang.resolve.java.structure.JavaElementCollectionFromPsiArrayUtil.packages;
-
-public class JavaPackage extends JavaElementImpl {
-    public JavaPackage(@NotNull PsiPackage psiPackage) {
-        super(psiPackage);
-    }
-
+public interface JavaPackage extends JavaElement {
     @NotNull
     @Override
-    public PsiPackage getPsi() {
-        return (PsiPackage) super.getPsi();
-    }
+    PsiPackage getPsi();
 
     @NotNull
-    public Collection<JavaClass> getClasses() {
-        return classes(getPsi().getClasses());
-    }
+    Collection<JavaClass> getClasses();
 
     @NotNull
-    public Collection<JavaPackage> getSubPackages() {
-        return packages(getPsi().getSubPackages());
-    }
+    Collection<JavaPackage> getSubPackages();
 
     @NotNull
-    public FqName getFqName() {
-        return new FqName(getPsi().getQualifiedName());
-    }
+    FqName getFqName();
 }

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

@@ -0,0 +1,56 @@
+/*
+ * 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.PsiPackage;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.jet.lang.resolve.name.FqName;
+
+import java.util.Collection;
+
+import static org.jetbrains.jet.lang.resolve.java.structure.JavaElementCollectionFromPsiArrayUtil.classes;
+import static org.jetbrains.jet.lang.resolve.java.structure.JavaElementCollectionFromPsiArrayUtil.packages;
+
+public class JavaPackageImpl extends JavaElementImpl implements JavaPackage {
+    public JavaPackageImpl(@NotNull PsiPackage psiPackage) {
+        super(psiPackage);
+    }
+
+    @NotNull
+    @Override
+    public PsiPackage getPsi() {
+        return (PsiPackage) super.getPsi();
+    }
+
+    @Override
+    @NotNull
+    public Collection<JavaClass> getClasses() {
+        return classes(getPsi().getClasses());
+    }
+
+    @Override
+    @NotNull
+    public Collection<JavaPackage> getSubPackages() {
+        return packages(getPsi().getSubPackages());
+    }
+
+    @Override
+    @NotNull
+    public FqName getFqName() {
+        return new FqName(getPsi().getQualifiedName());
+    }
+}