/*
* Copyright (c) 2008-2015 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.SingleResultCallback;
import com.mongodb.binding.AsyncReadBinding;
import com.mongodb.binding.ReadBinding;
import com.mongodb.connection.AsyncConnection;
import com.mongodb.connection.Connection;
import com.mongodb.connection.QueryResult;
import com.mongodb.operation.CommandOperationHelper.CommandTransformer;
import org.bson.BsonDocument;
import org.bson.BsonString;
import org.bson.codecs.BsonDocumentCodec;
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.OperationHelper.AsyncCallableWithConnection;
import static com.mongodb.operation.OperationHelper.CallableWithConnection;
import static com.mongodb.operation.OperationHelper.LOGGER;
import static com.mongodb.operation.OperationHelper.releasingCallback;
import static com.mongodb.operation.OperationHelper.serverIsAtLeastVersionTwoDotSix;
import static com.mongodb.operation.OperationHelper.withConnection;
/**
* An operation that determines if a user exists.
*
* @since 3.0
*/
public class UserExistsOperation implements AsyncReadOperation<Boolean>, ReadOperation<Boolean> {
private final String databaseName;
private final String userName;
/**
* Construct a new instance.
*
* @param databaseName the name of the database for the operation.
* @param userName the name of the user to check if they exist.
*/
public UserExistsOperation(final String databaseName, final String userName) {
this.databaseName = notNull("databaseName", databaseName);
this.userName = notNull("userName", userName);
}
@Override
public Boolean execute(final ReadBinding binding) {
return withConnection(binding, new CallableWithConnection<Boolean>() {
@Override
public Boolean call(final Connection connection) {
if (serverIsAtLeastVersionTwoDotSix(connection.getDescription())) {
return executeWrappedCommandProtocol(binding, databaseName, getCommand(), connection, transformer());
} else {
return transformQueryResult().apply(connection.query(new MongoNamespace(databaseName, "system.users"),
new BsonDocument("user", new BsonString(userName)), null, 0, 1, 0,
binding.getReadPreference().isSlaveOk(), false,
false, false, false, false,
new BsonDocumentCodec()),
connection.getDescription().getServerAddress());
}
}
});
}
@Override
public void executeAsync(final AsyncReadBinding binding, final SingleResultCallback<Boolean> callback) {
withConnection(binding, new AsyncCallableWithConnection() {
@Override
public void call(final AsyncConnection connection, final Throwable t) {
SingleResultCallback<Boolean> errHandlingCallback = errorHandlingCallback(callback, LOGGER);
if (t != null) {
errHandlingCallback.onResult(null, t);
} else {
final SingleResultCallback<Boolean> wrappedCallback = releasingCallback(errHandlingCallback, connection);
if (serverIsAtLeastVersionTwoDotSix(connection.getDescription())) {
executeWrappedCommandProtocolAsync(binding, databaseName, getCommand(), new BsonDocumentCodec(), connection,
transformer(), wrappedCallback);
} else {
connection.queryAsync(new MongoNamespace(databaseName, "system.users"),
new BsonDocument("user", new BsonString(userName)), null, 0, 1, 0,
binding.getReadPreference().isSlaveOk(), false,
false, false, false, false,
new BsonDocumentCodec(),
new SingleResultCallback<QueryResult<BsonDocument>>() {
@Override
public void onResult(final QueryResult<BsonDocument> result, final Throwable t) {
if (t != null) {
wrappedCallback.onResult(null, t);
} else {
try {
wrappedCallback.onResult(transformQueryResult().apply(result,
connection.getDescription()
.getServerAddress()),
null);
} catch (Throwable tr) {
wrappedCallback.onResult(null, tr);
}
}
}
});
}
}
}
});
}
private CommandTransformer<BsonDocument, Boolean> transformer() {
return new CommandTransformer<BsonDocument, Boolean>() {
@Override
public Boolean apply(final BsonDocument result, final ServerAddress serverAddress) {
return result.get("users").isArray() && !result.getArray("users").isEmpty();
}
};
}
private CommandTransformer<QueryResult<BsonDocument>, Boolean> transformQueryResult() {
return new CommandTransformer<QueryResult<BsonDocument>, Boolean>() {
@Override
public Boolean apply(final QueryResult<BsonDocument> queryResult, final ServerAddress serverAddress) {
return !queryResult.getResults().isEmpty();
}
};
}
private BsonDocument getCommand() {
return new BsonDocument("usersInfo", new BsonString(userName));
}
}