/*
* Copyright 2015-2016 MongoDB, Inc.
*
* 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 com.mongodb;
import org.bson.BsonDocument;
import org.bson.BsonString;
import static com.mongodb.assertions.Assertions.notNull;
/**
* A read concern allows clients to choose a level of isolation for their reads.
*
* @mongodb.server.release 3.2
* @mongodb.driver.manual reference/readConcern/ Read Concern
* @since 3.2
*/
public final class ReadConcern {
private final ReadConcernLevel readConcernLevel;
/**
* Construct a new read concern
*
* @param readConcernLevel the read concern level
*/
public ReadConcern(final ReadConcernLevel readConcernLevel) {
this.readConcernLevel = notNull("readConcernLevel", readConcernLevel);
}
/**
* Use the servers default read concern.
*/
public static final ReadConcern DEFAULT = new ReadConcern();
/**
* The local read concern.
*/
public static final ReadConcern LOCAL = new ReadConcern(ReadConcernLevel.LOCAL);
/**
* The majority read concern.
*/
public static final ReadConcern MAJORITY = new ReadConcern(ReadConcernLevel.MAJORITY);
/**
* The linearizable read concern.
*
* <p>
* This read concern is only compatible with {@link ReadPreference#primary()}.
* </p>
*
* @since 3.4
* @mongodb.server.release 3.4
*/
public static final ReadConcern LINEARIZABLE = new ReadConcern(ReadConcernLevel.LINEARIZABLE);
/**
* @return true if this is the server default read concern
*/
public boolean isServerDefault() {
return readConcernLevel == null;
}
/**
* Gets this read concern as a document.
*
* @return The read concern as a BsonDocument
*/
public BsonDocument asDocument() {
BsonDocument readConcern = new BsonDocument();
if (!isServerDefault()){
readConcern.put("level", new BsonString(readConcernLevel.getValue()));
}
return readConcern;
}
@Override
public boolean equals(final Object o) {
if (this == o) {
return true;
}
if (o == null) {
return false;
}
if (getClass() != o.getClass()) {
return false;
}
ReadConcern that = (ReadConcern) o;
if (readConcernLevel != that.readConcernLevel) {
return false;
}
return true;
}
@Override
public int hashCode() {
return readConcernLevel != null ? readConcernLevel.hashCode() : 0;
}
private ReadConcern() {
this.readConcernLevel = null;
}
}