content: /*
   * Copyright 1999-2017 Alibaba Group.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.alibaba.p3c.pmd.lang.java.rule.oop;
  
  import java.util.List;
  
  import com.alibaba.p3c.pmd.lang.java.rule.AbstractAliRule;
  import com.alibaba.p3c.pmd.lang.java.rule.util.NodeUtils;
  import com.alibaba.p3c.pmd.lang.java.util.NumberConstants;
  
  import net.sourceforge.pmd.lang.java.ast.ASTEqualityExpression;
  import net.sourceforge.pmd.lang.java.ast.ASTPrimaryExpression;
  
  /**
   * [Mandatory] The wrapper classes should be compared by equals method rather than by symbol of '==' directly.
   *
   * @author zenghou.fw
   * @date 2016/11/22
   */
  public class WrapperTypeEqualityRule extends AbstractAliRule {
  
      @Override
      public Object visit(ASTEqualityExpression node, Object data) {
          final String literalPrefix = "PrimaryExpression/PrimaryPrefix/Literal";
          final String unaryExpression = "UnaryExpression";
          // null presents in either side of "==" or "!=" means no violation
          if (node.hasDescendantMatchingXPath(literalPrefix)
              || node.hasDescendantMatchingXPath(unaryExpression)) {
              return super.visit(node, data);
          }
  
          // possible elements around "==" are PrimaryExpression or UnaryExpression(e.g. a == -2)
          List<ASTPrimaryExpression> expressions = node.findChildrenOfType(ASTPrimaryExpression.class);
          if (expressions.size() == NumberConstants.INTEGER_SIZE_OR_LENGTH_2) {
              // PMD can not resolve array length type, but only the
              ASTPrimaryExpression left = expressions.get(0);
              ASTPrimaryExpression right = expressions.get(1);
              // if left is complex expression, skip
              if (left.jjtGetNumChildren() > 1) {
                  return super.visit(node, data);
              }
              boolean bothArrayLength = isArrayLength(left) && isArrayLength(right);
              boolean bothWrapperType = NodeUtils.isWrapperType(left) && NodeUtils.isWrapperType(right);
  
              if (!bothArrayLength && bothWrapperType) {
                  addViolationWithMessage(data, node, "java.oop.WrapperTypeEqualityRule.violation.msg");
              }
          }
  
          return super.visit(node, data);
      }
  
      private boolean isArrayLength(ASTPrimaryExpression expression) {
          // assume expression like "x.length" is the length of array, field with name "length" may result in
          // misrecognition
          return "length".equals(expression.jjtGetLastToken().getImage())
              && ".".equals(expression.jjtGetFirstToken().getNext().getImage());
      }
  
  }
  