contrib/storage-phoenix/src/main/java/org/apache/drill/exec/store/phoenix/PhoenixScanBatchCreator.java

package org.apache.drill.exec.store.phoenix;

import java.util.List;

import org.apache.drill.common.exceptions.ChildErrorContext;
import org.apache.drill.common.exceptions.ExecutionSetupException;
import org.apache.drill.common.exceptions.UserException;
import org.apache.drill.common.types.TypeProtos.MinorType;
import org.apache.drill.common.types.Types;
import org.apache.drill.exec.ops.ExecutorFragmentContext;
import org.apache.drill.exec.physical.impl.BatchCreator;
import org.apache.drill.exec.physical.impl.scan.framework.ManagedReader;
import org.apache.drill.exec.physical.impl.scan.framework.ManagedScanFramework;
import org.apache.drill.exec.physical.impl.scan.framework.ManagedScanFramework.ReaderFactory;
import org.apache.drill.exec.physical.impl.scan.framework.ManagedScanFramework.ScanFrameworkBuilder;
import org.apache.drill.exec.physical.impl.scan.framework.SchemaNegotiator;
import org.apache.drill.exec.record.CloseableRecordBatch;
import org.apache.drill.exec.record.RecordBatch;
import org.apache.drill.exec.server.options.OptionManager;

public class PhoenixScanBatchCreator implements BatchCreator<PhoenixSubScan> {

  @Override
  public CloseableRecordBatch getBatch(ExecutorFragmentContext context, PhoenixSubScan subScan, List<RecordBatch> children) throws ExecutionSetupException {
    try {
      ScanFrameworkBuilder builder = createBuilder(context.getOptions(), subScan);
      return builder.buildScanOperator(context, subScan);
    } catch (UserException e) {
      throw e;
    } catch (Throwable e) {
      throw new ExecutionSetupException(e);
    }
  }

  private ScanFrameworkBuilder createBuilder(OptionManager options, PhoenixSubScan subScan) {
    ScanFrameworkBuilder builder = new ScanFrameworkBuilder();
    builder.projection(subScan.getColumns());
    builder.setUserName(subScan.getUserName());

    builder.errorContext(new ChildErrorContext(builder.errorContext()) {

      @Override
      public void addContext(UserException.Builder builder) {
        builder.addContext("tableName", subScan.getScanSpec().getTableName());
      }

    });

    ReaderFactory readerFactory = new PhoenixReaderFactory(subScan);
    builder.setReaderFactory(readerFactory);
    builder.nullType(Types.optional(MinorType.VARCHAR));

    return builder;
  }

  private static class PhoenixReaderFactory implements ReaderFactory {

    private final PhoenixSubScan subScan;
    private int count;

    public PhoenixReaderFactory(PhoenixSubScan subScan) {
      this.subScan = subScan;
    }

    @Override
    public void bind(ManagedScanFramework framework) {  }

    @Override
    public ManagedReader<? extends SchemaNegotiator> next() {
      String tableName = subScan.getScanSpec().getTableName();
      if (count++ == 0) {
        if (tableName.startsWith("my")) {
          return new PhoenixBatchReader(subScan);
        }
      }
      return null;
    }
  }
}