org.dizitart.no2.repository.Cursor Maven / Gradle / Ivy
/*
* Copyright (c) 2017-2020. Nitrite 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.dizitart.no2.repository;
import org.dizitart.no2.collection.FindPlan;
import org.dizitart.no2.common.Lookup;
import org.dizitart.no2.common.RecordStream;
/**
* An interface to iterate over {@link ObjectRepository#find()} results.
*
* @author Anindya Chatterjee
* @since 1.0
*/
public interface Cursor extends RecordStream {
/**
* Gets a filter plan for the query.
*
* @return the filter plan
*/
FindPlan getFindPlan();
/**
* Projects the result of one type into an {@link Iterable} of another type.
*
* @param the type of the target objects.
* @param projectionType the projection type.
* @return java.lang.Iterable of projected objects.
*/
RecordStream
project(Class
projectionType);
/**
* Performs a left outer join with a foreign cursor with the specified lookup parameters.
*
* It performs an equality match on the localField to the foreignField from the objects of the foreign cursor.
* If an input object does not contain the localField, the join treats the field as having a value of null
* for matching purposes.
*
* @param the type of the foreign object.
* @param the type of the joined object.
* @param foreignCursor the foreign cursor for the join.
* @param lookup the lookup parameter for the join operation.
* @param type the type of the joined record.
* @return a lazy iterable of joined objects.
* @since 2.1.0
*/
RecordStream join(Cursor foreignCursor, Lookup lookup, Class type);
}