org.dizitart.no2.Cursor Maven / Gradle / Ivy
/*
*
* Copyright 2017-2018 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;
import java.util.Set;
/**
* An interface to iterate over database {@code find()} results. It provides a
* mechanism to iterate over all {@link NitriteId}s of the result.
*
* [[app-listing]]
* [source,java]
* . Example of {@link Cursor}
* --
* // create/open a database
* Nitrite db = Nitrite.builder()
* .openOrCreate("user", "password");
*
* // create a collection named - test
* NitriteCollection collection = db.getCollection("test");
*
* // returns all ids un-filtered
* Cursor result = collection.find();
*
* for (Document doc : result) {
* // use your logic with the retrieved doc here
* }
*
*
* --
*
* [icon="{@docRoot}/note.png"]
* NOTE: To create an iterator over the documents instead of the ids,
* call on the {@link Cursor}.
*
* @author Anindya Chatterjee
* @since 1.0
*/
public interface Cursor extends RecordIterable {
/**
* Gets a lazy iterable containing all the selected keys of the result documents.
*
* @param projection the selected keys of a result document.
* @return a lazy iterable of documents.
*/
RecordIterable project(Document projection);
/**
* 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 documents of the foreign cursor.
* If an input document does not contain the localField, the join treats the field as having a value of `null`
* for matching purposes.
*
* @param foreignCursor the foreign cursor for the join.
* @param lookup the lookup parameter for the join operation.
*
* @return a lazy iterable of joined documents.
* @since 2.1.0
*/
RecordIterable join(Cursor foreignCursor, Lookup lookup);
/**
* Gets the set of all {@link NitriteId}s from the {@code find()} results.
*
* @return a set of all {@link NitriteId}s.
* @since 3.3.0
*/
Set idSet();
}