CurrentUser.java

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// distributed with this work for additional information
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// to you 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
//
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package org.apache.doris.nereids.trees.expressions.functions.scalar;

import org.apache.doris.catalog.FunctionSignature;
import org.apache.doris.nereids.trees.expressions.functions.AlwaysNotNullable;
import org.apache.doris.nereids.trees.expressions.functions.ExplicitlyCastableSignature;
import org.apache.doris.nereids.trees.expressions.shape.LeafExpression;
import org.apache.doris.nereids.trees.expressions.visitor.ExpressionVisitor;
import org.apache.doris.nereids.types.StringType;

import com.google.common.collect.ImmutableList;

import java.util.List;

/**
 * ScalarFunction 'CurrentUser'.
 */
public class CurrentUser extends ScalarFunction
        implements LeafExpression, ExplicitlyCastableSignature, AlwaysNotNullable {

    public static final List<FunctionSignature> SIGNATURES = ImmutableList.of(
            FunctionSignature.ret(StringType.INSTANCE).args()
    );

    public CurrentUser() {
        super("current_user", ImmutableList.of());
    }

    @Override
    public List<FunctionSignature> getSignatures() {
        return SIGNATURES;
    }

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

    @Override
    public boolean isDeterministic() {
        return false;
    }
}