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The MongoDB Java Driver uber-artifact, containing the legacy driver, the mongodb-driver, mongodb-driver-core, and bson
/*
* Copyright 2008-present 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.operation;
import com.mongodb.MongoNamespace;
import com.mongodb.ServerAddress;
import com.mongodb.async.AsyncBatchCursor;
import com.mongodb.async.SingleResultCallback;
import com.mongodb.binding.AsyncConnectionSource;
import com.mongodb.binding.AsyncReadBinding;
import com.mongodb.binding.ConnectionSource;
import com.mongodb.binding.ReadBinding;
import com.mongodb.client.model.Collation;
import com.mongodb.connection.AsyncConnection;
import com.mongodb.connection.Connection;
import com.mongodb.connection.ConnectionDescription;
import com.mongodb.connection.QueryResult;
import com.mongodb.operation.CommandOperationHelper.CommandTransformer;
import com.mongodb.operation.OperationHelper.AsyncCallableWithConnectionAndSource;
import com.mongodb.operation.OperationHelper.CallableWithConnectionAndSource;
import com.mongodb.session.SessionContext;
import org.bson.BsonDocument;
import org.bson.BsonString;
import org.bson.codecs.Codec;
import org.bson.codecs.Decoder;
import java.util.concurrent.TimeUnit;
import static com.mongodb.assertions.Assertions.notNull;
import static com.mongodb.internal.async.ErrorHandlingResultCallback.errorHandlingCallback;
import static com.mongodb.operation.CommandOperationHelper.executeWrappedCommandProtocol;
import static com.mongodb.operation.CommandOperationHelper.executeWrappedCommandProtocolAsync;
import static com.mongodb.operation.DocumentHelper.putIfNotNullOrEmpty;
import static com.mongodb.operation.DocumentHelper.putIfNotZero;
import static com.mongodb.operation.OperationHelper.LOGGER;
import static com.mongodb.operation.OperationHelper.releasingCallback;
import static com.mongodb.operation.OperationHelper.validateReadConcernAndCollation;
import static com.mongodb.operation.OperationHelper.withConnection;
import static com.mongodb.operation.OperationReadConcernHelper.appendReadConcernToCommand;
/**
* Finds the distinct values for a specified field across a single collection.
*
* When possible, the distinct command uses an index to find documents and return values.
*
* @param the type of the distinct value
* @mongodb.driver.manual reference/command/distinct Distinct Command
* @since 3.0
*/
public class DistinctOperation implements AsyncReadOperation>, ReadOperation> {
private static final String VALUES = "values";
private final MongoNamespace namespace;
private final String fieldName;
private final Decoder decoder;
private BsonDocument filter;
private long maxTimeMS;
private Collation collation;
/**
* Construct an instance.
*
* @param namespace the database and collection namespace for the operation.
* @param fieldName the name of the field to return distinct values.
* @param decoder the decoder for the result documents.
*/
public DistinctOperation(final MongoNamespace namespace, final String fieldName, final Decoder decoder) {
this.namespace = notNull("namespace", namespace);
this.fieldName = notNull("fieldName", fieldName);
this.decoder = notNull("decoder", decoder);
}
/**
* Gets the query filter.
*
* @return the query filter
* @mongodb.driver.manual reference/method/db.collection.find/ Filter
*/
public BsonDocument getFilter() {
return filter;
}
/**
* Sets the query filter to apply to the query.
*
* @param filter the query filter, which may be null.
* @return this
* @mongodb.driver.manual reference/method/db.collection.find/ Filter
*/
public DistinctOperation filter(final BsonDocument filter) {
this.filter = filter;
return this;
}
/**
* Gets the maximum execution time on the server for this operation. The default is 0, which places no limit on the execution time.
*
* @param timeUnit the time unit to return the result in
* @return the maximum execution time in the given time unit
*/
public long getMaxTime(final TimeUnit timeUnit) {
notNull("timeUnit", timeUnit);
return timeUnit.convert(maxTimeMS, TimeUnit.MILLISECONDS);
}
/**
* Sets the maximum execution time on the server for this operation.
*
* @param maxTime the max time
* @param timeUnit the time unit, which may not be null
* @return this
*/
public DistinctOperation maxTime(final long maxTime, final TimeUnit timeUnit) {
notNull("timeUnit", timeUnit);
this.maxTimeMS = TimeUnit.MILLISECONDS.convert(maxTime, timeUnit);
return this;
}
/**
* Returns the collation options
*
* @return the collation options
* @since 3.4
* @mongodb.server.release 3.4
*/
public Collation getCollation() {
return collation;
}
/**
* Sets the collation options
*
* A null value represents the server default.
* @param collation the collation options to use
* @return this
* @since 3.4
* @mongodb.server.release 3.4
*/
public DistinctOperation collation(final Collation collation) {
this.collation = collation;
return this;
}
@Override
public BatchCursor execute(final ReadBinding binding) {
return withConnection(binding, new CallableWithConnectionAndSource>() {
@Override
public BatchCursor call(final ConnectionSource source, final Connection connection) {
validateReadConcernAndCollation(connection, binding.getSessionContext().getReadConcern(), collation);
return executeWrappedCommandProtocol(binding, namespace.getDatabaseName(), getCommand(binding.getSessionContext()),
createCommandDecoder(), connection, transformer(source, connection));
}
});
}
@Override
public void executeAsync(final AsyncReadBinding binding, final SingleResultCallback> callback) {
withConnection(binding, new AsyncCallableWithConnectionAndSource() {
@Override
public void call(final AsyncConnectionSource source, final AsyncConnection connection, final Throwable t) {
SingleResultCallback> errHandlingCallback = errorHandlingCallback(callback, LOGGER);
if (t != null) {
errHandlingCallback.onResult(null, t);
} else {
final SingleResultCallback> wrappedCallback = releasingCallback(
errHandlingCallback, source, connection);
validateReadConcernAndCollation(source, connection, binding.getSessionContext().getReadConcern(), collation,
new AsyncCallableWithConnectionAndSource() {
@Override
public void call(final AsyncConnectionSource source, final AsyncConnection connection, final Throwable t) {
if (t != null) {
wrappedCallback.onResult(null, t);
} else {
executeWrappedCommandProtocolAsync(binding, namespace.getDatabaseName(),
getCommand(binding.getSessionContext()), createCommandDecoder(),
connection, asyncTransformer(connection.getDescription()), wrappedCallback);
}
}
});
}
}
});
}
private Codec createCommandDecoder() {
return CommandResultDocumentCodec.create(decoder, VALUES);
}
private QueryResult createQueryResult(final BsonDocument result, final ConnectionDescription description) {
return new QueryResult(namespace, BsonDocumentWrapperHelper.toList(result, VALUES), 0L,
description.getServerAddress());
}
private CommandTransformer> transformer(final ConnectionSource source, final Connection connection) {
return new CommandTransformer>() {
@Override
public BatchCursor apply(final BsonDocument result, final ServerAddress serverAddress) {
QueryResult queryResult = createQueryResult(result, connection.getDescription());
return new QueryBatchCursor(queryResult, 0, 0, decoder, source);
}
};
}
private CommandTransformer> asyncTransformer(final ConnectionDescription connectionDescription) {
return new CommandTransformer>() {
@Override
public AsyncBatchCursor apply(final BsonDocument result, final ServerAddress serverAddress) {
QueryResult queryResult = createQueryResult(result, connectionDescription);
return new AsyncSingleBatchQueryCursor(queryResult);
}
};
}
private BsonDocument getCommand(final SessionContext sessionContext) {
BsonDocument commandDocument = new BsonDocument("distinct", new BsonString(namespace.getCollectionName()));
appendReadConcernToCommand(sessionContext, commandDocument);
commandDocument.put("key", new BsonString(fieldName));
putIfNotNullOrEmpty(commandDocument, "query", filter);
putIfNotZero(commandDocument, "maxTimeMS", maxTimeMS);
if (collation != null) {
commandDocument.put("collation", collation.asDocument());
}
return commandDocument;
}
}