FunctionExpression.java example

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/*
 * Licensed to CRATE Technology GmbH ("Crate") under one or more contributor
 * license agreements.  See the NOTICE file distributed with this work for
 * additional information regarding copyright ownership.  Crate licenses
 * this file 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
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 * However, if you have executed another commercial license agreement
 * with Crate these terms will supersede the license and you may use the
 * software solely pursuant to the terms of the relevant commercial agreement.
 */

package io.crate.operation.aggregation;

import io.crate.metadata.Scalar;
import io.crate.data.Input;

import java.util.Arrays;

public class FunctionExpression<ReturnType, InputType> implements Input<ReturnType> {

    private final Input<InputType>[] childInputs;
    private Scalar<ReturnType, InputType> functionImplementation;

    public FunctionExpression(Scalar<ReturnType, InputType> functionImplementation, Input<InputType>[] childInputs) {
        this.functionImplementation = functionImplementation;
        this.childInputs = childInputs;
    }

    @Override
    public ReturnType value() {
        return functionImplementation.evaluate(childInputs);
    }

    @Override
    public String toString() {
        return "FuncExpr{" +
               functionImplementation.info().ident().name() +
               ", args=" + Arrays.toString(childInputs) + '}';
    }
}