/*
* Copyright 2013 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;
import org.springframework.data.mongodb.core.aggregation.AggregationExpressionTransformer.AggregationExpressionTransformationContext;
import org.springframework.data.mongodb.core.aggregation.ExposedFields.FieldReference;
import org.springframework.data.mongodb.core.spel.ExpressionNode;
import org.springframework.data.mongodb.core.spel.ExpressionTransformationContextSupport;
import org.springframework.data.mongodb.core.spel.ExpressionTransformer;
import org.springframework.util.Assert;
/**
* Interface to type an {@link ExpressionTransformer} to the contained
* {@link AggregationExpressionTransformationContext}.
*
* @author Oliver Gierke
* @author Christoph Strobl
* @since 1.4
*/
interface AggregationExpressionTransformer
extends ExpressionTransformer<AggregationExpressionTransformationContext<ExpressionNode>> {
/**
* A special {@link ExpressionTransformationContextSupport} to be aware of the {@link AggregationOperationContext}.
*
* @author Oliver Gierke
* @author Thomas Darimont
*/
class AggregationExpressionTransformationContext<T extends ExpressionNode>
extends ExpressionTransformationContextSupport<T> {
private final AggregationOperationContext aggregationContext;
/**
* Creates an {@link AggregationExpressionTransformationContext}.
*
* @param currentNode must not be {@literal null}.
* @param parentNode
* @param previousOperationObject
* @param aggregationContext must not be {@literal null}.
*/
public AggregationExpressionTransformationContext(T currentNode, ExpressionNode parentNode,
Document previousOperationObject, AggregationOperationContext context) {
super(currentNode, parentNode, previousOperationObject);
Assert.notNull(context, "AggregationOperationContext must not be null!");
this.aggregationContext = context;
}
/**
* Returns the underlying {@link AggregationOperationContext}.
*
* @return
*/
public AggregationOperationContext getAggregationContext() {
return aggregationContext;
}
/**
* Returns the {@link FieldReference} for the current {@link ExpressionNode}.
*
* @return
*/
public FieldReference getFieldReference() {
return aggregationContext.getReference(getCurrentNode().getName());
}
}
}