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1   /*
2    * Copyright 2021 TiKV Project Authors.
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   */
17  
18  package org.tikv.common.expression;
19  
20  import java.io.Serializable;
21  import java.util.List;
22  import org.tikv.common.types.DataType;
23  
24  public abstract class Expression implements Serializable {
25    protected DataType dataType;
26    protected boolean resolved;
27  
28    public Expression(DataType dataType) {
29      this.dataType = dataType;
30      this.resolved = true;
31    }
32  
33    public Expression() {
34      this.resolved = false;
35    }
36  
37    public abstract List<Expression> getChildren();
38  
39    public abstract <R, C> R accept(Visitor<R, C> visitor, C context);
40  
41    public boolean isResolved() {
42      return getChildren().stream().allMatch(Expression::isResolved);
43    }
44  
45    public DataType getDataType() {
46      return dataType;
47    }
48  
49    public void setDataType(DataType dataType) {
50      this.dataType = dataType;
51    }
52  }