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

   1 /*
   2  * Copyright 2003-2008 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.intellij.psi.util.PsiTreeUtil;
  20 import com.siyeh.HardcodedMethodConstants;
  21 import org.jetbrains.annotations.NotNull;
  22
  23 class ParameterClassCheckVisitor extends JavaRecursiveElementVisitor{
  24
  25     private final PsiParameter parameter;
  26
  27     private boolean checked = false;
  28
  29     ParameterClassCheckVisitor(PsiParameter parameter){
  30         super();
  31         this.parameter = parameter;
  32     }
  33
  34     @Override public void visitElement(@NotNull PsiElement element){
  35         if(!checked){
  36             super.visitElement(element);
  37         }
  38     }
  39
  40     @Override public void visitMethodCallExpression(
  41             @NotNull PsiMethodCallExpression expression){
  42         if(checked){
  43             return;
  44         }
  45         super.visitMethodCallExpression(expression);
  46         final PsiReferenceExpression methodExpression =
  47                 expression.getMethodExpression();
  48         final String methodName = methodExpression.getReferenceName();
  49         if(!HardcodedMethodConstants.GET_CLASS.equals(methodName)){
  50             return;
  51         }
  52         final PsiExpressionList argumentList = expression.getArgumentList();
  53         final PsiExpression[] arguments = argumentList.getExpressions();
  54         if(arguments.length != 0){
  55             return;
  56         }
  57         final PsiExpression qualifier =
  58                 methodExpression.getQualifierExpression();
  59         if(isParameterReference(qualifier)){
  60             checked = true;
  61         }
  62     }
  63
  64     @Override public void visitInstanceOfExpression(
  65             @NotNull PsiInstanceOfExpression expression){
  66         if(checked){
  67             return;
  68         }
  69         super.visitInstanceOfExpression(expression);
  70         final PsiExpression operand = expression.getOperand();
  71         if(isParameterReference(operand)){
  72             checked = true;
  73         }
  74     }
  75
  76     @Override public void visitTypeCastExpression(
  77             PsiTypeCastExpression expression) {
  78         if(checked){
  79             return;
  80         }
  81         super.visitTypeCastExpression(expression);
  82         final PsiExpression operand = expression.getOperand();
  83         if(!isParameterReference(operand)){
  84             return;
  85         }
  86         final PsiTryStatement statement =
  87                 PsiTreeUtil.getParentOfType(expression, PsiTryStatement.class);
  88         if(statement == null){
  89             return;
  90         }
  91         final PsiParameter[] parameters = statement.getCatchBlockParameters();
  92         if(parameters.length < 2){
  93             return;
  94         }
  95         boolean nullPointerExceptionFound = false;
  96         boolean classCastExceptionFound = false;
  97         for(PsiParameter parameter : parameters){
  98             final PsiType type = parameter.getType();
  99             if(type.equalsToText("java.lang.NullPointerException")){
 100                 nullPointerExceptionFound = true;
 101                 if(classCastExceptionFound){
 102                     break;
 103                 }
 104             } else if(type.equalsToText("java.lang.ClassCastException")){
 105                 classCastExceptionFound = true;
 106                 if(nullPointerExceptionFound){
 107                     break;
 108                 }
 109             }
 110         }
 111         if(classCastExceptionFound && nullPointerExceptionFound){
 112             checked = true;
 113         }
 114     }
 115
 116     private boolean isParameterReference(PsiExpression operand){
 117         if(operand == null){
 118             return false;
 119         }
 120         if(!(operand instanceof PsiReferenceExpression)){
 121             return false;
 122         }
 123         final PsiReferenceExpression expression =
 124                 (PsiReferenceExpression)operand;
 125         final PsiElement referent = expression.resolve();
 126         return referent != null && referent.equals(parameter);
 127     }
 128
 129     public boolean isChecked(){
 130         return checked;
 131     }
 132 }