plugins/InspectionGadgets/src/com/siyeh/ig/bugs/StringEqualityInspection.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.psi.*;
  19 import com.siyeh.InspectionGadgetsBundle;
  20 import com.siyeh.ig.BaseInspection;
  21 import com.siyeh.ig.BaseInspectionVisitor;
  22 import com.siyeh.ig.InspectionGadgetsFix;
  23 import com.siyeh.ig.fixes.EqualityToEqualsFix;
  24 import com.siyeh.ig.psiutils.ComparisonUtils;
  25 import com.siyeh.ig.psiutils.TypeUtils;
  26 import org.jetbrains.annotations.NotNull;
  27
  28 public class StringEqualityInspection extends BaseInspection {
  29
  30     @NotNull
  31     public String getDisplayName() {
  32         return InspectionGadgetsBundle.message(
  33                 "string.comparison.display.name");
  34     }
  35
  36     @NotNull
  37     public String buildErrorString(Object... infos) {
  38         return InspectionGadgetsBundle.message(
  39                 "string.comparison.problem.descriptor");
  40     }
  41
  42     public boolean isEnabledByDefault(){
  43         return true;
  44     }
  45
  46     public BaseInspectionVisitor buildVisitor() {
  47         return new ObjectEqualityVisitor();
  48     }
  49
  50     public InspectionGadgetsFix buildFix(Object... infos) {
  51         return new EqualityToEqualsFix();
  52     }
  53
  54     private static class ObjectEqualityVisitor extends BaseInspectionVisitor {
  55
  56         @Override public void visitBinaryExpression(
  57                 @NotNull PsiBinaryExpression expression) {
  58             super.visitBinaryExpression(expression);
  59             if(!(expression.getROperand() != null)){
  60                 return;
  61             }
  62             if (!ComparisonUtils.isEqualityComparison(expression)) {
  63                 return;
  64             }
  65             final PsiExpression lhs = expression.getLOperand();
  66             if (!isStringType(lhs)) {
  67                 return;
  68             }
  69             final PsiExpression rhs = expression.getROperand();
  70             if (!isStringType(rhs)) {
  71                 return;
  72             }
  73             final String lhsText = lhs.getText();
  74             if (PsiKeyword.NULL.equals(lhsText)) {
  75                 return;
  76             }
  77             if (rhs == null) {
  78                 return;
  79             }
  80             final String rhsText = rhs.getText();
  81             if (PsiKeyword.NULL.equals(rhsText)) {
  82                 return;
  83             }
  84             final PsiJavaToken sign = expression.getOperationSign();
  85             registerError(sign);
  86         }
  87
  88         private static boolean isStringType(PsiExpression lhs) {
  89             if (lhs == null) {
  90                 return false;
  91             }
  92             final PsiType lhsType = lhs.getType();
  93             if (lhsType == null) {
  94                 return false;
  95             }
  96             return TypeUtils.isJavaLangString(lhsType);
  97         }
  98     }
  99 }