after instanceof, prefer interfaces and abstract classes

java/java-impl/src/com/intellij/codeInsight/completion/PreferAbstractWeigher.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2000-2010 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 com.intellij.codeInsight.completion;
+
+import com.intellij.codeInsight.lookup.LookupElement;
+import com.intellij.psi.*;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * @author peter
+*/
+public class PreferAbstractWeigher extends CompletionWeigher {
+
+  public Comparable weigh(@NotNull final LookupElement item, @Nullable final CompletionLocation location) {
+    if (location == null || location.getCompletionType() != CompletionType.SMART) {
+      return null;
+    }
+
+    final PsiElement position = location.getCompletionParameters().getPosition();
+    final PsiElement parent = position.getParent();
+    if (!(parent instanceof PsiJavaCodeReferenceElement) ||
+        !(parent.getParent() instanceof PsiTypeElement) ||
+        !(parent.getParent().getParent() instanceof PsiInstanceOfExpression)) {
+      return null;
+    }
+
+    final Object object = item.getObject();
+    if (object instanceof PsiClass) {
+      final PsiClass aClass = (PsiClass)object;
+      if (aClass.isInterface()) {
+        return 2;
+      }
+      if (aClass.hasModifierProperty(PsiModifier.ABSTRACT)) {
+        return 1;
+      }
+    }
+
+    return 0;
+  }
+}

java/java-impl/src/com/intellij/psi/util/proximity/ExplicitlyImportedWeigher.java

@@ -38,7 +38,9 @@ public class ExplicitlyImportedWeigher extends ProximityWeigher {
           final PsiImportList importList = psiJavaFile.getImportList();
           if (importList != null) {
             for (final PsiImportStatement importStatement : importList.getImportStatements()) {
-              if (!importStatement.isOnDemand() && qname.equals(importStatement.getQualifiedName())) {
+              final boolean onDemand = importStatement.isOnDemand();
+              final String imported = importStatement.getQualifiedName();
+              if (onDemand && qname.startsWith(imported + ".") || !onDemand && qname.equals(imported)) {
                 return true;
               }
             }

java/java-tests/testData/codeInsight/completion/smartTypeSorting/PreferInterfaces.java

@@ -0,0 +1,14 @@
+package zzzzz;
+
+public class Holder {
+  {
+    Foo foo = null;
+    if (foo instanceof <caret>)
+  }
+
+}
+
+interface Foo {}
+interface IFoo extends Foo {}
+abstract class Goo implements IFoo {}
+class Bar extends Goo {}

java/java-tests/testSrc/com/intellij/codeInsight/completion/SmartTypeCompletionOrderingTest.java

@@ -203,6 +203,10 @@ public class SmartTypeCompletionOrderingTest extends CompletionSortingTestCase {
     checkPreferredItems(0, "Goo", "InnerGoo", "Bar", "AGoo");
   }
 
+  public void testPreferInterfaces() throws Throwable {
+    checkPreferredItems(0, "IFoo", "Goo", "Bar");
+  }
+
   public void testLocalVariablesOutweighStats() throws Throwable {
     final LookupImpl lookup = invokeCompletion(BASE_PATH + "/" + getTestName(false) + ".java");
     assertPreferredItems(0, "foo", "param", "this", "bar", "goo");

resources/src/META-INF/IdeaPlugin.xml

@@ -803,8 +803,10 @@
     <weigher key="completion" implementationClass="com.intellij.codeInsight.completion.NameEndMatchingDegreeWeigher" id="nameEnd"
              order="after expectedType, before stats"/>
 
-    <weigher key="completion" implementationClass="com.intellij.codeInsight.completion.PreferNonGenericWeigher" id="nonGeneric"
+    <weigher key="completion" implementationClass="com.intellij.codeInsight.completion.PreferAbstractWeigher" id="abstract"
              order="after prefix"/>
+    <weigher key="completion" implementationClass="com.intellij.codeInsight.completion.PreferNonGenericWeigher" id="nonGeneric"
+             order="after abstract"/>
     <weigher key="completion" implementationClass="com.intellij.codeInsight.completion.PreferAccessibleWeigher" id="accessible"
              order="after nonGeneric"/>
     <weigher key="completion" implementationClass="com.intellij.codeInsight.completion.PreferSimpleWeigher" id="simple"