/*
* Copyright 2013-2017 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 java.util.Collections;
import java.util.Iterator;
import java.util.List;
import org.bson.Document;
import org.springframework.util.Assert;
/**
* Collects the results of executing an aggregation operation.
*
* @author Tobias Trelle
* @author Oliver Gierke
* @author Thomas Darimont
* @author Christoph Strobl
* @author Mark Paluch
* @param <T> The class in which the results are mapped onto.
* @since 1.3
*/
public class AggregationResults<T> implements Iterable<T> {
private final List<T> mappedResults;
private final Document rawResults;
private final String serverUsed;
/**
* Creates a new {@link AggregationResults} instance from the given mapped and raw results.
*
* @param mappedResults must not be {@literal null}.
* @param rawResults must not be {@literal null}.
*/
public AggregationResults(List<T> mappedResults, Document rawResults) {
Assert.notNull(mappedResults, "List of mapped results must not be null!");
Assert.notNull(rawResults, "Raw results must not be null!");
this.mappedResults = Collections.unmodifiableList(mappedResults);
this.rawResults = rawResults;
this.serverUsed = parseServerUsed();
}
/**
* Returns the aggregation results.
*
* @return
*/
public List<T> getMappedResults() {
return mappedResults;
}
/**
* Returns the unique mapped result. Assumes no result or exactly one.
*
* @return
* @throws IllegalArgumentException in case more than one result is available.
*/
public T getUniqueMappedResult() {
Assert.isTrue(mappedResults.size() < 2, "Expected unique result or null, but got more than one!");
return mappedResults.size() == 1 ? mappedResults.get(0) : null;
}
/*
* (non-Javadoc)
* @see java.lang.Iterable#iterator()
*/
public Iterator<T> iterator() {
return mappedResults.iterator();
}
/**
* Returns the server that has been used to perform the aggregation.
*
* @return
*/
public String getServerUsed() {
return serverUsed;
}
/**
* Returns the raw result that was returned by the server.
*
* @return
* @since 1.6
*/
public Document getRawResults() {
return rawResults;
}
private String parseServerUsed() {
Object object = rawResults.get("serverUsed");
return object instanceof String ? (String) object : null;
}
}