| /* |
| * 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.resultSet.impl; |
| |
| import org.apache.drill.exec.physical.resultSet.PushResultSetReader; |
| import org.apache.drill.exec.physical.rowSet.DirectRowSet; |
| import org.apache.drill.exec.physical.rowSet.IndirectRowSet; |
| import org.apache.drill.exec.physical.rowSet.RowSet; |
| import org.apache.drill.exec.physical.rowSet.RowSetReader; |
| import org.apache.drill.exec.record.VectorContainer; |
| import org.apache.drill.exec.record.selection.SelectionVector2; |
| import org.apache.drill.shaded.guava.com.google.common.base.Preconditions; |
| |
| public class PushResultSetReaderImpl implements PushResultSetReader { |
| |
| public interface UpstreamSource { |
| int schemaVersion(); |
| VectorContainer batch(); |
| SelectionVector2 sv2(); |
| } |
| |
| public static class BatchHolder implements UpstreamSource { |
| |
| private final VectorContainer container; |
| private int schemaVersion; |
| |
| public BatchHolder(VectorContainer container) { |
| this.container = container; |
| } |
| |
| public void newBatch() { |
| if (schemaVersion == 0) { |
| schemaVersion = 1; |
| } else if (container.isSchemaChanged()) { |
| schemaVersion++; |
| } |
| } |
| |
| @Override |
| public int schemaVersion() { return schemaVersion; } |
| |
| @Override |
| public VectorContainer batch() { return container; } |
| |
| @Override |
| public SelectionVector2 sv2() { return null; } |
| } |
| |
| private final UpstreamSource source; |
| private int priorSchemaVersion; |
| private RowSetReader rowSetReader; |
| |
| public PushResultSetReaderImpl(UpstreamSource source) { |
| this.source = source; |
| } |
| |
| @Override |
| public RowSetReader start() { |
| int sourceSchemaVersion = source.schemaVersion(); |
| Preconditions.checkState(sourceSchemaVersion > 0); |
| Preconditions.checkState(priorSchemaVersion <= sourceSchemaVersion); |
| |
| // If new schema, discard the old reader (if any, and create |
| // a new one that matches the new schema. If not a new schema, |
| // then the old reader is reused: it points to vectors which |
| // Drill requires be the same vectors as the previous batch, |
| // but with different buffers. |
| boolean newSchema = priorSchemaVersion != sourceSchemaVersion; |
| if (newSchema) { |
| rowSetReader = createRowSet().reader(); |
| priorSchemaVersion = sourceSchemaVersion; |
| } else { |
| rowSetReader.newBatch(); |
| } |
| return rowSetReader; |
| } |
| |
| // TODO: Build the reader without the need for a row set |
| private RowSet createRowSet() { |
| VectorContainer container = source.batch(); |
| switch (container.getSchema().getSelectionVectorMode()) { |
| case FOUR_BYTE: |
| throw new IllegalArgumentException("Build from SV4 not yet supported"); |
| case NONE: |
| return DirectRowSet.fromContainer(container); |
| case TWO_BYTE: |
| return IndirectRowSet.fromSv2(container, source.sv2()); |
| default: |
| throw new IllegalStateException("Invalid selection mode"); |
| } |
| } |
| } |