| /* |
| * 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.druid.segment.virtual; |
| |
| import org.apache.druid.segment.ColumnInspector; |
| import org.apache.druid.segment.VirtualColumns; |
| import org.apache.druid.segment.column.ColumnCapabilities; |
| |
| import javax.annotation.Nullable; |
| |
| /** |
| * Provides {@link ColumnCapabilities} for both virtual and non-virtual columns by building on top of another base |
| * {@link ColumnInspector}. |
| * |
| * {@link VirtualColumns} are provided with the base inspector so that they may potentially infer output types to |
| * construct the appropriate capabilities for virtual columns, while the base inspector directly supplies the |
| * capabilities for non-virtual columns. |
| */ |
| public class VirtualizedColumnInspector implements ColumnInspector |
| { |
| protected final VirtualColumns virtualColumns; |
| protected final ColumnInspector baseInspector; |
| |
| public VirtualizedColumnInspector( |
| ColumnInspector baseInspector, |
| VirtualColumns virtualColumns |
| ) |
| { |
| this.virtualColumns = virtualColumns; |
| this.baseInspector = baseInspector; |
| } |
| |
| @Nullable |
| @Override |
| public ColumnCapabilities getColumnCapabilities(String columnName) |
| { |
| if (virtualColumns.exists(columnName)) { |
| return virtualColumns.getColumnCapabilities(baseInspector, columnName); |
| } else { |
| return baseInspector.getColumnCapabilities(columnName); |
| } |
| } |
| } |