FirstValue.java

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

import org.apache.doris.nereids.trees.expressions.Expression;
import org.apache.doris.nereids.trees.expressions.visitor.ExpressionVisitor;
import org.apache.doris.nereids.types.DataType;

import com.google.common.base.Preconditions;

import java.util.List;

/**
 * Window function: First_value()
 */
public class FirstValue extends FirstOrLastValue {

    public FirstValue(Expression child) {
        super("first_value", child);
    }

    public FirstValue(Expression child, Expression ignoreNullValue) {
        super("first_value", child, ignoreNullValue);
    }

    public FirstValue(List<Expression> children) {
        super("first_value", children);
    }

    @Override
    public FirstValue withChildren(List<Expression> children) {
        Preconditions.checkArgument(children.size() == 1 || children.size() == 2);
        return new FirstValue(children);
    }

    @Override
    public <R, C> R accept(ExpressionVisitor<R, C> visitor, C context) {
        return visitor.visitFirstValue(this, context);
    }

    @Override
    public DataType getDataType() {
        return child(0).getDataType();
    }
}