org.apache.hadoop.hbase.regionserver.InternalScanner Maven / Gradle / Ivy
/**
*
* 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.hadoop.hbase.regionserver;
import java.io.Closeable;
import java.io.IOException;
import java.util.List;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.HBaseInterfaceAudience;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.classification.InterfaceStability;
/**
* Internal scanners differ from client-side scanners in that they operate on
* HStoreKeys and byte[] instead of RowResults. This is because they are
* actually close to how the data is physically stored, and therefore it is more
* convenient to interact with them that way. It is also much easier to merge
* the results across SortedMaps than RowResults.
*
* Additionally, we need to be able to determine if the scanner is doing
* wildcard column matches (when only a column family is specified or if a
* column regex is specified) or if multiple members of the same column family
* were specified. If so, we need to ignore the timestamp to ensure that we get
* all the family members, as they may have been last updated at different
* times.
*/
@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC)
@InterfaceStability.Evolving
public interface InternalScanner extends Closeable {
/**
* Grab the next row's worth of values.
* @param results return output array
* @return true if more rows exist after this one, false if scanner is done
* @throws IOException e
*/
boolean next(List results) throws IOException;
/**
* Grab the next row's worth of values.
* @param result return output array
* @param scannerContext
* @return true if more rows exist after this one, false if scanner is done
* @throws IOException e
*/
boolean next(List| result, ScannerContext scannerContext) throws IOException;
/**
* Closes the scanner and releases any resources it has allocated
* @throws IOException
*/
@Override
void close() throws IOException;
}
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