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This module contains the Table/SQL API for writing table programs within the table ecosystem using the Java programming language.

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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.
 */

package org.apache.flink.table.operations;

import org.apache.flink.annotation.Internal;
import org.apache.flink.table.catalog.ResolvedSchema;
import org.apache.flink.table.expressions.ResolvedExpression;

import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

/**
 * Relational operation that performs computations on top of subsets of input rows grouped by key.
 */
@Internal
public class AggregateQueryOperation implements QueryOperation {

    private final List groupingExpressions;
    private final List aggregateExpressions;
    private final QueryOperation child;
    private final ResolvedSchema resolvedSchema;

    public AggregateQueryOperation(
            List groupingExpressions,
            List aggregateExpressions,
            QueryOperation child,
            ResolvedSchema resolvedSchema) {
        this.groupingExpressions = groupingExpressions;
        this.aggregateExpressions = aggregateExpressions;
        this.child = child;
        this.resolvedSchema = resolvedSchema;
    }

    @Override
    public ResolvedSchema getResolvedSchema() {
        return resolvedSchema;
    }

    @Override
    public String asSummaryString() {
        Map args = new LinkedHashMap<>();
        args.put("group", groupingExpressions);
        args.put("agg", aggregateExpressions);

        return OperationUtils.formatWithChildren(
                "Aggregate", args, getChildren(), Operation::asSummaryString);
    }

    public List getGroupingExpressions() {
        return groupingExpressions;
    }

    public List getAggregateExpressions() {
        return aggregateExpressions;
    }

    @Override
    public List getChildren() {
        return Collections.singletonList(child);
    }

    @Override
    public  T accept(QueryOperationVisitor visitor) {
        return visitor.visit(this);
    }
}