/*
* Copyright 2015-2016 the original author or authors.
*
* Licensed 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.springframework.data.mongodb.core.aggregation;
import org.bson.Document;
/**
* An {@link AggregationExpression} can be used with field expressions in aggregation pipeline stages like
* {@code project} and {@code group}.
*
* @author Thomas Darimont
* @author Oliver Gierke
* @author Christoph Strobl
*/
public interface AggregationExpression {
/**
* Turns the {@link AggregationExpression} into a {@link Document} within the given
* {@link AggregationOperationContext}.
*
* @param context
* @return
*/
Document toDocument(AggregationOperationContext context);
}