org.apache.metamodel.mongodb.common.MongoDBUtils Maven / Gradle / Ivy
/**
* 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.metamodel.mongodb.common;
import java.util.List;
import java.util.Map;
import org.apache.metamodel.data.DataSetHeader;
import org.apache.metamodel.data.DefaultRow;
import org.apache.metamodel.data.Row;
import org.apache.metamodel.query.SelectItem;
import org.apache.metamodel.schema.Column;
import org.apache.metamodel.util.CollectionUtils;
import com.mongodb.DBObject;
/**
* A utility class for MongoDB module.
*/
public class MongoDBUtils {
/**
* Converts a MongoDB data object {@link DBObject} into MetaModel
* {@link Row}.
*
* @param dbObject
* a MongoDB object storing data.
* @param header
* a header describing the columns of the data stored.
* @return the MetaModel {@link Row} result object.
*/
public static Row toRow(DBObject dbObject, DataSetHeader header) {
if (dbObject == null) {
return null;
}
final Map map = dbObject.toMap();
return toRow(map, header);
}
/**
* Converts a map into MetaModel. This map stores data of a MongoDB document.
*
* @param map
* a map object storing data of a MongoDB document.
* @param header
* a header describing the columns of the data stored.
* @return the MetaModel {@link Row} result object.
*/
public static Row toRow(Map map, DataSetHeader header) {
if (map == null) {
return null;
}
final int size = header.size();
final Object[] values = new Object[size];
for (int i = 0; i < values.length; i++) {
final SelectItem selectItem = header.getSelectItem(i);
final String key = selectItem.getColumn().getName();
final Object value = CollectionUtils.find(map, key);
values[i] = toValue(selectItem.getColumn(), value);
}
return new DefaultRow(header, values);
}
private static Object toValue(Column column, Object value) {
if (value instanceof List) {
return value;
}
if (value instanceof DBObject) {
DBObject basicDBObject = (DBObject) value;
return basicDBObject.toMap();
}
return value;
}
}