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

   1 /*
   2  * Copyright (c) 2000-2005 by JetBrains s.r.o. All Rights Reserved.
   3  * Use is subject to license terms.
   4  */
   5 package com.intellij.codeInsight.completion;
   6
   7 import com.intellij.codeInsight.ExpectedTypeInfo;
   8 import com.intellij.codeInsight.lookup.LookupElement;
   9 import com.intellij.openapi.util.NullableLazyKey;
  10 import com.intellij.openapi.util.Pair;
  11 import com.intellij.psi.PsiClass;
  12 import com.intellij.psi.PsiType;
  13 import com.intellij.psi.PsiTypeParameter;
  14 import com.intellij.psi.util.PsiUtil;
  15 import com.intellij.psi.util.TypeConversionUtil;
  16 import com.intellij.util.NullableFunction;
  17 import org.jetbrains.annotations.NotNull;
  18 import org.jetbrains.annotations.Nullable;
  19
  20 /**
  21  * @author peter
  22 */
  23 public class PreferDefaultTypeWeigher extends CompletionWeigher {
  24   private static final NullableLazyKey<PsiTypeParameter, CompletionLocation> TYPE_PARAMETER = NullableLazyKey.create("expectedTypes", new NullableFunction<CompletionLocation, PsiTypeParameter>() {
  25     @Nullable
  26     public PsiTypeParameter fun(final CompletionLocation location) {
  27       final Pair<PsiClass,Integer> pair =
  28           JavaSmartCompletionContributor.getTypeParameterInfo(location.getCompletionParameters().getPosition());
  29       if (pair == null) return null;
  30       return pair.first.getTypeParameters()[pair.second.intValue()];
  31     }
  32   });
  33
  34
  35   private enum MyResult {
  36     normal,
  37     exactlyExpected,
  38     ofDefaultType,
  39     exactlyDefault,
  40     expectedNoSelect
  41   }
  42
  43   public MyResult weigh(@NotNull final LookupElement item, final CompletionLocation location) {
  44     final Object object = item.getObject();
  45     if (location.getCompletionType() != CompletionType.SMART) return MyResult.normal;
  46
  47     if (object instanceof PsiClass) {
  48       final PsiTypeParameter parameter = TYPE_PARAMETER.getValue(location);
  49       if (parameter != null && object.equals(PsiUtil.resolveClassInType(TypeConversionUtil.typeParameterErasure(parameter)))) {
  50         return MyResult.exactlyExpected;
  51       }
  52     }
  53
  54     ExpectedTypeInfo[] expectedInfos = JavaCompletionUtil.EXPECTED_TYPES.getValue(location);
  55     if (expectedInfos == null) return MyResult.normal;
  56
  57     PsiType itemType = JavaCompletionUtil.getLookupElementType(item);
  58     if (itemType == null || !itemType.isValid()) return MyResult.normal;
  59
  60     if (object instanceof PsiClass) {
  61       for (final ExpectedTypeInfo info : expectedInfos) {
  62         if (TypeConversionUtil.erasure(info.getType().getDeepComponentType()).equals(TypeConversionUtil.erasure(itemType))) {
  63           return AbstractExpectedTypeSkipper.skips(item, location) ? MyResult.expectedNoSelect : MyResult.exactlyExpected;
  64         }
  65       }
  66     }
  67
  68     for (final ExpectedTypeInfo expectedInfo : expectedInfos) {
  69       final PsiType defaultType = expectedInfo.getDefaultType();
  70       final PsiType expectedType = expectedInfo.getType();
  71       if (!expectedType.isValid()) {
  72         return MyResult.normal;
  73       }
  74
  75       if (defaultType != expectedType) {
  76         if (defaultType.equals(itemType)) {
  77           return MyResult.exactlyDefault;
  78         }
  79
  80         if (defaultType.isAssignableFrom(itemType)) {
  81           return MyResult.ofDefaultType;
  82         }
  83       }
  84       if (PsiType.VOID.equals(itemType) && PsiType.VOID.equals(expectedType)) {
  85         return MyResult.exactlyExpected;
  86       }
  87     }
  88
  89     return MyResult.normal;
  90   }
  91 }