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.set;
  
  import java.util.List;
  
  import com.alibaba.p3c.pmd.lang.java.rule.AbstractAliRule;
  
  import net.sourceforge.pmd.lang.ast.Node;
  import net.sourceforge.pmd.lang.java.ast.ASTBlock;
  import net.sourceforge.pmd.lang.java.ast.ASTClassOrInterfaceDeclaration;
  import net.sourceforge.pmd.lang.java.ast.ASTName;
  import net.sourceforge.pmd.lang.java.ast.ASTVariableDeclarator;
  import net.sourceforge.pmd.lang.java.ast.ASTVariableDeclaratorId;
  import org.jaxen.JaxenException;
  
  /**
   * [Mandatory] Do not use methods which will modify the list after using Arrays.asList to convert array to list,
   * otherwise methods like add/remove/clear will throw UnsupportedOperationException.
   *
   * @author shengfang.gsf
   * @date 2016/12/13
   */
  public class UnsupportedExceptionWithModifyAsListRule extends AbstractAliRule {
  
      private final static String ADD = ".add";
      private final static String REMOVE = ".remove";
      private final static String CLEAR = ".clear";
      private final static String XPATH
          = "//VariableDeclarator[../Type/ReferenceType/ClassOrInterfaceType[@Image='List']]/VariableInitializer"
          + "/Expression/PrimaryExpression/PrimaryPrefix/Name[@Image='Arrays.asList']";
      private final static String CHILD_XPATH
          = "BlockStatement/Statement/StatementExpression/PrimaryExpression/PrimaryPrefix/Name";
  
      @Override
      public Object visit(ASTClassOrInterfaceDeclaration node, Object data) {
          if (node.isInterface()) {
              return data;
          }
          try {
              // find Array.asList variable
              List<Node> nodes = node.findChildNodesWithXPath(XPATH);
              for (Node item : nodes) {
                  if (!(item instanceof ASTName)) {
                      continue;
                  }
                  List<ASTVariableDeclarator> parents =
                      item.getParentsOfType(ASTVariableDeclarator.class);
                  if (parents == null || parents.size() == 0 || parents.size() > 1) {
                      continue;
                  }
                  ASTVariableDeclarator declarator = parents.get(0);
                  ASTVariableDeclaratorId variableName =
                      declarator.getFirstChildOfType(ASTVariableDeclaratorId.class);
  
                  String valName = variableName.getImage();
                  // find Variable scope code block
                  ASTBlock blockNode = variableName.getFirstParentOfType(ASTBlock.class);
                  if (blockNode == null || valName == null) {
                      continue;
                  }
                  List<Node> blockNodes = blockNode.findChildNodesWithXPath(CHILD_XPATH);
                  // variable.add .removed is forbbiden.
                  for (Node blockItem : blockNodes) {
                      if (blockItem.getBeginLine() < item.getBeginLine()) {
                          continue;
                      }
                      if (checkBlockNodesValid(valName, blockItem)) {
                          addViolationWithMessage(data, blockItem,
                              "java.set.UnsupportedExceptionWithModifyAsListRule.violation.msg",
                              new Object[] {blockItem.getImage()});
                      }
                  }
  
              }
          } catch (JaxenException e) {
              e.printStackTrace();
          }
          return super.visit(node, data);
      }
  
      /**
       * Only to find out whether there is any violation within the scope of the corresponding method
       *
       * @param variableName
       * @param item
       * @return
       * @throws JaxenException
       */
      private boolean checkBlockNodesValid(String variableName, Node item) {
          if (item instanceof ASTName) {
              String name = item.getImage();
              if (judgeName(name, variableName)) {
                  return true;
              }
          }
          return false;
      }
  
      /**
       * judge name equels t.add t.remove t.clear
       *
       * @param name
       * @param variableName
       * @return
       */
      private boolean judgeName(String name, String variableName) {
          return name.equals(variableName + ADD) || name.equals(variableName + REMOVE)
              || name.equals(variableName + CLEAR);
      }
  
  }
  