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

   1 /*
   2  * Copyright 2000-2009 JetBrains s.r.o.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 package com.intellij.psi.util.proximity;
  17
  18 import com.intellij.psi.*;
  19 import com.intellij.psi.util.ProximityLocation;
  20 import com.intellij.psi.util.PsiTreeUtil;
  21 import org.jetbrains.annotations.NotNull;
  22 import org.jetbrains.annotations.NonNls;
  23 import org.jetbrains.annotations.Nullable;
  24
  25 /**
  26  * @author peter
  27 */
  28 public class JavaInheritanceWeigher extends ProximityWeigher {
  29
  30   public Comparable weigh(@NotNull final PsiElement element, final ProximityLocation location) {
  31     final PsiElement position = location.getPosition();
  32     PsiClass placeClass = PsiTreeUtil.getContextOfType(element, PsiClass.class, false);
  33     if (position.getParent() instanceof PsiReferenceExpression) {
  34       final PsiExpression qualifierExpression = ((PsiReferenceExpression)position.getParent()).getQualifierExpression();
  35       if (qualifierExpression != null) {
  36         final PsiType type = qualifierExpression.getType();
  37         if (type instanceof PsiClassType) {
  38           final PsiClass psiClass = ((PsiClassType)type).resolve();
  39           if (psiClass != null) {
  40             placeClass = psiClass;
  41           }
  42         }
  43       }
  44     }
  45
  46     if (element instanceof PsiClass && isTooGeneral((PsiClass)element)) return false;
  47     if (element instanceof PsiMethod && isTooGeneral(((PsiMethod)element).getContainingClass())) return false;
  48
  49     PsiClass contextClass = PsiTreeUtil.getContextOfType(position, PsiClass.class, false);
  50     while (contextClass != null) {
  51       PsiClass elementClass = placeClass;
  52       while (elementClass != null) {
  53         if (contextClass.isInheritor(elementClass, true)) return true;
  54         elementClass = elementClass.getContainingClass();
  55       }
  56       contextClass = contextClass.getContainingClass();
  57     }
  58     return false;
  59   }
  60
  61   private static boolean isTooGeneral(@Nullable final PsiClass element) {
  62     if (element == null) return true;
  63
  64     @NonNls final String qname = element.getQualifiedName();
  65     return qname == null || qname.startsWith("java.lang.");
  66   }
  67 }