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.dialect.db2.ast.stmt;
  
  import com.alibaba.druid.DbType;
  import com.alibaba.druid.sql.ast.SQLExpr;
  import com.alibaba.druid.sql.ast.expr.SQLIntegerExpr;
  import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
  import com.alibaba.druid.sql.dialect.db2.ast.DB2Object;
  import com.alibaba.druid.sql.dialect.db2.visitor.DB2ASTVisitor;
  import com.alibaba.druid.sql.dialect.db2.visitor.DB2OutputVisitor;
  import com.alibaba.druid.sql.visitor.SQLASTVisitor;
  
  public class DB2SelectQueryBlock extends SQLSelectQueryBlock implements DB2Object {
      private Isolation isolation;
  
      private LockRequest lockRequest;
  
      private boolean forReadOnly;
  
      private SQLExpr optimizeFor;
  
      @Override
      protected void accept0(SQLASTVisitor visitor) {
          if (visitor instanceof DB2ASTVisitor) {
              accept0((DB2ASTVisitor) visitor);
              return;
          }
  
          super.accept0(visitor);
      }
  
      @Override
      public void accept0(DB2ASTVisitor visitor) {
          if (visitor.visit(this)) {
              acceptChild(visitor, this.selectList);
              acceptChild(visitor, this.from);
              acceptChild(visitor, this.where);
              acceptChild(visitor, this.groupBy);
              acceptChild(visitor, this.getFirst());
          }
          visitor.endVisit(this);
      }
  
      public DB2SelectQueryBlock() {
          dbType = DbType.db2;
      }
  
      public Isolation getIsolation() {
          return isolation;
      }
  
      public void setIsolation(Isolation isolation) {
          this.isolation = isolation;
      }
  
      public LockRequest getLockRequest() {
          return lockRequest;
      }
  
      public void setLockRequest(LockRequest lockRequest) {
          this.lockRequest = lockRequest;
      }
  
      public boolean isForReadOnly() {
          return forReadOnly;
      }
  
      public void setForReadOnly(boolean forReadOnly) {
          this.forReadOnly = forReadOnly;
      }
  
      public SQLExpr getOptimizeFor() {
          return optimizeFor;
      }
  
      public void setOptimizeFor(SQLExpr optimizeFor) {
          this.optimizeFor = optimizeFor;
      }
  
      public static enum Isolation {
          RR, RS, CS, UR
      }
  
      public static enum LockRequest {
          SHARE, UPDATE, EXCLUSIVE;
      }
  
      public void limit(int rowCount, int offset) {
          if (offset <= 0) {
              setFirst(new SQLIntegerExpr(rowCount));
          } else {
              throw new UnsupportedOperationException("not support offset");
          }
      }
  
      public void output(StringBuilder buf) {
          this.accept(
                  new DB2OutputVisitor(buf)
          );
      }
  }
  