com.facebook.presto.decoder.dummy.DummyRowDecoder Maven / Gradle / Ivy
/*
* Licensed 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 com.facebook.presto.decoder.dummy;
import com.facebook.presto.decoder.DecoderColumnHandle;
import com.facebook.presto.decoder.FieldValueProvider;
import com.facebook.presto.decoder.RowDecoder;
import com.google.common.collect.ImmutableMap;
import java.util.Map;
import java.util.Optional;
/**
* The row decoder for the 'dummy' format. For an unstructured row format (bag
* of bytes), a specific decoder for a topic must exist. To start developing
* such a decoder, it is beneficial to be able to configure an arbitrary topic
* to be available through presto without any decoding at all (not even line
* parsing) and examine the internal rows that are exposed by Presto. By adding
* a table name to the catalog configuration file and not having and specific
* topic description JSON file (or by omitting the 'dataFormat' field in the
* table description file), this decoder should be selected by the appropriate
* connector.
*/
public class DummyRowDecoder
implements RowDecoder
{
public static final String NAME = "dummy";
private static final Optional> ALL_NULLS = Optional.of(ImmutableMap.of());
@Override
public Optional> decodeRow(byte[] data,
Map dataMap)
{
return ALL_NULLS;
}
}