plugins/InspectionGadgets/src/com/siyeh/ig/bugs/CovariantCompareToInspection.java

   1 /*
   2  * Copyright 2003-2007 Dave Griffith, Bas Leijdekkers
   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.siyeh.ig.bugs;
  17
  18 import com.intellij.openapi.project.Project;
  19 import com.intellij.psi.*;
  20 import com.intellij.psi.search.GlobalSearchScope;
  21 import com.intellij.psi.util.TypeConversionUtil;
  22 import com.siyeh.HardcodedMethodConstants;
  23 import com.siyeh.InspectionGadgetsBundle;
  24 import com.siyeh.ig.BaseInspection;
  25 import com.siyeh.ig.BaseInspectionVisitor;
  26 import com.siyeh.ig.psiutils.MethodUtils;
  27 import com.siyeh.ig.psiutils.TypeUtils;
  28 import org.jetbrains.annotations.NotNull;
  29
  30 public class CovariantCompareToInspection extends BaseInspection {
  31
  32   @NotNull
  33   public String getDisplayName() {
  34         return InspectionGadgetsBundle.message(
  35                 "covariant.compareto.display.name");
  36     }
  37
  38     @NotNull
  39     public String buildErrorString(Object... infos) {
  40         return InspectionGadgetsBundle.message(
  41                 "covariant.compareto.problem.descriptor");
  42     }
  43
  44     public BaseInspectionVisitor buildVisitor() {
  45         return new CovariantCompareToVisitor();
  46     }
  47
  48     private static class CovariantCompareToVisitor
  49             extends BaseInspectionVisitor {
  50
  51         @Override public void visitMethod(@NotNull PsiMethod method) {
  52             // note: no call to super
  53             final String name = method.getName();
  54             if (!HardcodedMethodConstants.COMPARE_TO.equals(name)) {
  55                 return;
  56             }
  57             if (!method.hasModifierProperty(PsiModifier.PUBLIC)) {
  58                 return;
  59             }
  60             final PsiParameterList parameterList = method.getParameterList();
  61             if (parameterList.getParametersCount() != 1) {
  62                 return;
  63             }
  64             final PsiParameter[] parameters = parameterList.getParameters();
  65             final PsiType paramType = parameters[0].getType();
  66             if (TypeUtils.isJavaLangObject(paramType)) {
  67                 return;
  68             }
  69             final PsiClass aClass = method.getContainingClass();
  70             if (aClass == null) {
  71                 return;
  72             }
  73             final PsiMethod[] methods = aClass.findMethodsByName(
  74                     HardcodedMethodConstants.COMPARE_TO, false);
  75             for(PsiMethod compareToMethod : methods){
  76                 if(isNonVariantCompareTo(compareToMethod)){
  77                     return;
  78                 }
  79             }
  80             final PsiManager manager = method.getManager();
  81           final PsiClass comparableClass =
  82             JavaPsiFacade.getInstance(manager.getProject()).findClass("java.lang.Comparable", method.getResolveScope());
  83             if (comparableClass != null &&
  84                     comparableClass.getTypeParameters().length == 1) {
  85                 final PsiSubstitutor superSubstitutor =
  86                         TypeConversionUtil.getClassSubstitutor(comparableClass,
  87                                 aClass, PsiSubstitutor.EMPTY);
  88                 //null iff aClass is not inheritor of comparableClass
  89                 if (superSubstitutor != null) {
  90                     final PsiType substituted =
  91                             superSubstitutor.substitute(
  92                                     comparableClass.getTypeParameters()[0]);
  93                     if (paramType.equals(substituted)) {
  94                         return;
  95                     }
  96                 }
  97             }
  98             registerMethodError(method);
  99         }
 100
 101         private static boolean isNonVariantCompareTo(PsiMethod method) {
 102             final PsiManager manager = method.getManager();
 103             final Project project = method.getProject();
 104             final PsiClassType objectType = PsiType.getJavaLangObject(
 105                     manager, GlobalSearchScope.allScope(project));
 106             return MethodUtils.methodMatches(method, null, PsiType.INT,
 107                     HardcodedMethodConstants.COMPARE_TO, objectType);
 108         }
 109     }
 110 }