contrib/format-deltalake/src/main/java/org/apache/drill/exec/store/delta/format/DeltaFormatMatcher.java

/*
 * 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.store.delta.format;

import io.delta.standalone.DeltaLog;
import org.apache.drill.exec.planner.logical.DrillTable;
import org.apache.drill.exec.store.SchemaConfig;
import org.apache.drill.exec.store.dfs.DrillFileSystem;
import org.apache.drill.exec.store.dfs.FileSelection;
import org.apache.drill.exec.store.dfs.FileSystemPlugin;
import org.apache.drill.exec.store.dfs.FormatMatcher;
import org.apache.drill.exec.store.dfs.FormatPlugin;
import org.apache.drill.exec.store.dfs.FormatSelection;
import org.apache.drill.exec.store.plan.rel.PluginDrillTable;
import org.apache.hadoop.fs.FileStatus;

public class DeltaFormatMatcher extends FormatMatcher {

  private final DeltaFormatPlugin formatPlugin;

  public DeltaFormatMatcher(DeltaFormatPlugin formatPlugin) {
    this.formatPlugin = formatPlugin;
  }

  @Override
  public boolean supportDirectoryReads() {
    return true;
  }

  @Override
  public DrillTable isReadable(DrillFileSystem fs, FileSelection selection, FileSystemPlugin fsPlugin,
    String storageEngineName, SchemaConfig schemaConfig) {
    if (DeltaLog.forTable(fsPlugin.getFsConf(), selection.getSelectionRoot()).tableExists()) {
      FormatSelection formatSelection = new FormatSelection(formatPlugin.getConfig(), selection);
      return new PluginDrillTable(fsPlugin, storageEngineName, schemaConfig.getUserName(), formatSelection, formatPlugin.getConvention());
    }
    return null;
  }

  @Override
  public boolean isFileReadable(DrillFileSystem fs, FileStatus status) {
    return false;
  }

  @Override
  public FormatPlugin getFormatPlugin() {
    return formatPlugin;
  }

  public int priority() {
    return HIGH_PRIORITY;
  }
}