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//
//   http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.doris.nereids.trees;

import org.apache.doris.nereids.memo.GroupExpression;
import org.apache.doris.nereids.operators.Operator;

import java.util.List;

/**
 * interface for all node in Nereids, include plan node and expression.
 *
 * @param <NODE_TYPE> either {@link org.apache.doris.nereids.trees.plans.Plan}
 *                 or {@link org.apache.doris.nereids.trees.expressions.Expression}
 */
public interface TreeNode<NODE_TYPE extends TreeNode<NODE_TYPE>> {

    Operator getOperator();

    GroupExpression getGroupExpression();

    NodeType getType();

    <CHILD_TYPE extends TreeNode> List<CHILD_TYPE> children();

    <CHILD_TYPE extends TreeNode> CHILD_TYPE child(int index);

    int arity();

    NODE_TYPE newChildren(List<TreeNode> children);
}
