content: /*
   * Copyright 1999-2017 Alibaba Group Holding Ltd.
   *
   * 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.druid.sql.ast.expr;
  
  import com.alibaba.druid.sql.ast.*;
  import com.alibaba.druid.sql.visitor.SQLASTVisitor;
  
  import java.io.Serializable;
  import java.util.Collections;
  import java.util.List;
  
  public class SQLUnaryExpr extends SQLExprImpl implements Serializable, SQLReplaceable {
      private static final long serialVersionUID = 1L;
      private SQLExpr expr;
      private SQLUnaryOperator operator;
  
      public SQLUnaryExpr() {
      }
  
      public SQLUnaryExpr(SQLUnaryOperator operator, SQLExpr expr) {
          this.operator = operator;
          this.setExpr(expr);
      }
  
      public SQLUnaryExpr clone() {
          SQLUnaryExpr x = new SQLUnaryExpr();
          if (expr != null) {
              x.setExpr(expr.clone());
          }
          x.operator = operator;
          x.parenthesized = parenthesized;
          return x;
      }
  
      public SQLUnaryOperator getOperator() {
          return operator;
      }
  
      public void setOperator(SQLUnaryOperator operator) {
          this.operator = operator;
      }
  
      public SQLExpr getExpr() {
          return this.expr;
      }
  
      public void setExpr(SQLExpr expr) {
          if (expr != null) {
              expr.setParent(this);
          }
          this.expr = expr;
      }
  
      protected void accept0(SQLASTVisitor visitor) {
          if (visitor.visit(this)) {
              if (this.expr != null) {
                  this.expr.accept(visitor);
              }
          }
  
          visitor.endVisit(this);
      }
  
      @Override
      public List<SQLObject> getChildren() {
          return Collections.<SQLObject>singletonList(this.expr);
      }
  
      @Override
      public int hashCode() {
          final int prime = 31;
          int result = 1;
          result = prime * result + ((expr == null) ? 0 : expr.hashCode());
          result = prime * result + ((operator == null) ? 0 : operator.hashCode());
          return result;
      }
  
      @Override
      public boolean equals(Object obj) {
          if (this == obj) {
              return true;
          }
          if (obj == null) {
              return false;
          }
          if (getClass() != obj.getClass()) {
              return false;
          }
          SQLUnaryExpr other = (SQLUnaryExpr) obj;
          if (expr == null) {
              if (other.expr != null) {
                  return false;
              }
          } else if (!expr.equals(other.expr)) {
              return false;
          }
          if (operator != other.operator) {
              return false;
          }
          return true;
      }
  
      @Override
      public boolean replace(SQLExpr expr, SQLExpr target) {
          if (this.expr == expr) {
              setExpr(target);
              return true;
          }
          return false;
      }
  
      public SQLDataType computeDataType() {
          switch (operator) {
              case Plus:
              case Negative:
              case Compl:
              case Not:
                  return expr.computeDataType();
              default:
                  return null;
          }
      }
  }
  