| /* |
| * 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.drill.exec.physical.impl.protocol; |
| |
| import java.util.Collections; |
| import java.util.Iterator; |
| |
| import org.apache.drill.common.expression.SchemaPath; |
| import org.apache.drill.exec.record.BatchSchema; |
| import org.apache.drill.exec.record.RecordBatch; |
| import org.apache.drill.exec.record.TypedFieldId; |
| import org.apache.drill.exec.record.VectorContainer; |
| import org.apache.drill.exec.record.VectorWrapper; |
| import org.apache.drill.exec.record.WritableBatch; |
| import org.apache.drill.exec.record.selection.SelectionVector2; |
| import org.apache.drill.exec.record.selection.SelectionVector4; |
| |
| /** |
| * Wraps a vector container and optional selection vector in an interface |
| * simpler than the entire {@link RecordBatch}. This implementation hosts |
| * a container only. |
| * <p> |
| * Separates the idea of a batch schema and data batch. The accessor |
| * can identify a schema even if it has no batches. This occurs for |
| * readers that can identify the schema, but produce no actual data. |
| * <p> |
| * This version is designed for the the scan operator which will |
| * produce a series of different vector containers (which, oddly, must |
| * all contain the same vectors.) |
| */ |
| public class VectorContainerAccessor implements BatchAccessor { |
| |
| protected VectorContainer container; |
| private final SchemaTracker schemaTracker = new SchemaTracker(); |
| private int batchCount; |
| |
| /** |
| * Define a schema that does not necessarily contain any data. |
| * Call this to declare a schema when there are no results to |
| * report. |
| */ |
| public void setSchema(VectorContainer container) { |
| this.container = container; |
| if (container != null) { |
| schemaTracker.trackSchema(container); |
| } |
| } |
| |
| /** |
| * Define an output batch. Called each time a new batch is sent |
| * downstream. Checks if the schema of this batch is the same as |
| * that of any previous batch, and updates the schema version if |
| * the schema changes. May be called with the same container |
| * as the previous call, or a different one. A schema change occurs |
| * unless the vectors are identical across the two containers. |
| * |
| * @param container the container that holds vectors to be sent |
| * downstream |
| */ |
| public void addBatch(VectorContainer container) { |
| setSchema(container); |
| if (container != null) { |
| batchCount++; |
| } |
| } |
| |
| public int batchCount() { return batchCount; } |
| |
| @Override |
| public BatchSchema schema() { |
| return container == null ? null : container.getSchema(); |
| } |
| |
| @Override |
| public int schemaVersion() { return schemaTracker.schemaVersion(); } |
| |
| @Override |
| public int rowCount() { |
| return container == null ? 0 : container.getRecordCount(); |
| } |
| |
| @Override |
| public VectorContainer container() { return container; } |
| |
| @Override |
| public TypedFieldId getValueVectorId(SchemaPath path) { |
| return container.getValueVectorId(path); |
| } |
| |
| @Override |
| public VectorWrapper<?> getValueAccessorById(Class<?> clazz, int... ids) { |
| return container.getValueAccessorById(clazz, ids); |
| } |
| |
| @Override |
| public WritableBatch writableBatch() { |
| return WritableBatch.get(container); |
| } |
| |
| @Override |
| public SelectionVector2 selectionVector2() { |
| // Throws an exception by default because containers |
| // do not support selection vectors. |
| return container.getSelectionVector2(); |
| } |
| |
| @Override |
| public SelectionVector4 selectionVector4() { |
| // Throws an exception by default because containers |
| // do not support selection vectors. |
| return container.getSelectionVector4(); |
| } |
| |
| @Override |
| public Iterator<VectorWrapper<?>> iterator() { |
| if (container == null) { |
| return Collections.emptyIterator(); |
| } else { |
| return container.iterator(); |
| } |
| } |
| |
| @Override |
| public void release() { |
| if (container != null) { |
| container.zeroVectors(); |
| } |
| } |
| } |