java/java-impl/src/com/intellij/codeInsight/completion/PreferExpectedTypeWeigher.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.codeInsight.completion;
  17
  18 import com.intellij.codeInsight.ExpectedTypeInfo;
  19 import com.intellij.codeInsight.lookup.LookupElement;
  20 import com.intellij.psi.PsiClass;
  21 import com.intellij.psi.PsiType;
  22 import org.jetbrains.annotations.NotNull;
  23
  24 /**
  25  * @author peter
  26 */
  27 public class PreferExpectedTypeWeigher extends CompletionWeigher {
  28
  29   private enum MyResult {
  30     normal,
  31     expected,
  32     ofDefaultType,
  33   }
  34
  35   public MyResult weigh(@NotNull final LookupElement item, final CompletionLocation location) {
  36     if (location.getCompletionType() != CompletionType.BASIC) return MyResult.normal;
  37     if (item.getObject() instanceof PsiClass) return MyResult.normal;
  38
  39     ExpectedTypeInfo[] expectedInfos = JavaCompletionUtil.EXPECTED_TYPES.getValue(location);
  40     if (expectedInfos == null) return MyResult.normal;
  41
  42     PsiType itemType = JavaCompletionUtil.getLookupElementType(item);
  43     if (itemType == null || !itemType.isValid()) return MyResult.normal;
  44
  45     for (final ExpectedTypeInfo expectedInfo : expectedInfos) {
  46       final PsiType defaultType = expectedInfo.getDefaultType();
  47       final PsiType expectedType = expectedInfo.getType();
  48       if (!expectedType.isValid()) {
  49         return MyResult.normal;
  50       }
  51
  52       if (defaultType != expectedType && defaultType.isAssignableFrom(itemType)) {
  53         return MyResult.ofDefaultType;
  54       }
  55       if (expectedType.isAssignableFrom(itemType)) {
  56         return MyResult.expected;
  57       }
  58     }
  59
  60     return MyResult.normal;
  61   }
  62 }