XxHash64.java

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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.Expression;
import org.apache.doris.nereids.trees.expressions.functions.ExplicitlyCastableSignature;
import org.apache.doris.nereids.trees.expressions.functions.PropagateNullable;
import org.apache.doris.nereids.trees.expressions.visitor.ExpressionVisitor;
import org.apache.doris.nereids.types.BigIntType;
import org.apache.doris.nereids.types.StringType;
import org.apache.doris.nereids.types.VarcharType;
import org.apache.doris.nereids.util.ExpressionUtils;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;

import java.util.List;

/**
 * ScalarFunction 'xxhash_64'.
 */
public class XxHash64 extends ScalarFunction
        implements ExplicitlyCastableSignature, PropagateNullable {

    public static final List<FunctionSignature> SIGNATURES = ImmutableList.of(
            FunctionSignature.ret(BigIntType.INSTANCE).varArgs(VarcharType.SYSTEM_DEFAULT),
            FunctionSignature.ret(BigIntType.INSTANCE).varArgs(StringType.INSTANCE)
    );

    /**
     * constructor with 1 or more arguments.
     */
    public XxHash64(Expression arg, Expression... varArgs) {
        super("xxhash_64", ExpressionUtils.mergeArguments(arg, varArgs));
    }

    /**
     * withChildren.
     */
    @Override
    public XxHash64 withChildren(List<Expression> children) {
        Preconditions.checkArgument(children.size() >= 1);
        return new XxHash64(children.get(0),
                children.subList(1, children.size()).toArray(new Expression[0]));
    }

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

    @Override
    public <R, C> R accept(ExpressionVisitor<R, C> visitor, C context) {
        return visitor.visitXxHash64(this, context);
    }
}