FunctionParams.java

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package org.apache.doris.nereids.trees.expressions.functions;

import org.apache.doris.catalog.FunctionSignature;
import org.apache.doris.nereids.trees.expressions.Expression;

import java.util.List;
import java.util.Optional;
import java.util.function.Supplier;
import javax.annotation.Nullable;

/**
 * This class is used to reuse the origin function's signature to keep idempotent of compute signature.
 * You should provide a private/protected constructor to pass through FunctionParams to the super class(BoundFunction),
 * and override `withChildren(List<Expression> children)` to build FunctionParams and create a new function
 * with the FunctionParams
 */
public class FunctionParams {
    public final Optional<BoundFunction> originFunction;
    public final String functionName;
    public final List<Expression> arguments;
    public final boolean inferred;

    public FunctionParams(String functionName, List<Expression> arguments) {
        this(null, functionName, arguments, false);
    }

    public FunctionParams(
            @Nullable BoundFunction originFunction, String functionName,
            List<Expression> arguments, boolean inferred) {
        this.originFunction = Optional.ofNullable(originFunction);
        this.functionName = functionName;
        this.arguments = arguments;
        this.inferred = inferred;
    }

    public Supplier<FunctionSignature> getOriginSignature() {
        if (originFunction.isPresent()) {
            return () -> originFunction.get().getSignature();
        } else {
            return null;
        }
    }
}