| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.apache.iotdb.db.storageengine.dataregion; |
| |
| import org.apache.iotdb.commons.path.PartialPath; |
| import org.apache.iotdb.db.exception.query.QueryProcessException; |
| import org.apache.iotdb.db.queryengine.execution.fragment.QueryContext; |
| import org.apache.iotdb.db.storageengine.dataregion.read.QueryDataSource; |
| |
| import org.apache.tsfile.read.filter.basic.Filter; |
| |
| import java.util.Collections; |
| import java.util.List; |
| |
| /** |
| * It's a virtual data region used for query which contains time series that don't belong to any |
| * data region. |
| */ |
| public class VirtualDataRegion implements IDataRegionForQuery { |
| |
| private static final String VIRTUAL_DB_NAME = "root.__virtual"; |
| |
| private static final QueryDataSource EMPTY_QUERY_DATA_SOURCE = |
| new QueryDataSource(Collections.emptyList(), Collections.emptyList()); |
| |
| public static VirtualDataRegion getInstance() { |
| return VirtualDataRegion.InstanceHolder.INSTANCE; |
| } |
| |
| @Override |
| public void readLock() { |
| // do nothing, because itself is thread-safe already |
| } |
| |
| @Override |
| public void readUnlock() { |
| // do nothing, because itself is thread-safe already |
| } |
| |
| @Override |
| public QueryDataSource query( |
| List<PartialPath> pathList, |
| String singleDeviceId, |
| QueryContext context, |
| Filter globalTimeFilter, |
| List<Long> timePartitions) |
| throws QueryProcessException { |
| return EMPTY_QUERY_DATA_SOURCE; |
| } |
| |
| @Override |
| public long getDataTTL() { |
| return Long.MAX_VALUE; |
| } |
| |
| @Override |
| public String getDatabaseName() { |
| return VIRTUAL_DB_NAME; |
| } |
| |
| private static class InstanceHolder { |
| |
| private InstanceHolder() {} |
| |
| private static final VirtualDataRegion INSTANCE = new VirtualDataRegion(); |
| } |
| } |