/**
* 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.cassandra.cql.common;
import java.util.Collection;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;
import java.util.List;
import org.apache.cassandra.config.CFMetaData;
import org.apache.cassandra.cql.execution.RuntimeErrorMsg;
import org.apache.cassandra.db.ColumnFamily;
import org.apache.cassandra.db.IColumn;
import org.apache.cassandra.db.ReadCommand;
import org.apache.cassandra.db.Row;
import org.apache.cassandra.service.StorageProxy;
import org.apache.cassandra.service.StorageService;
import org.apache.cassandra.utils.LogUtil;
import org.apache.log4j.Logger;
/**
* A Row Source Defintion (RSD) for doing a super column range query on a Super Column Family.
*/
public class SuperColumnRangeQueryRSD extends RowSourceDef
{
private final static Logger logger_ = Logger.getLogger(SuperColumnRangeQueryRSD.class);
private CFMetaData cfMetaData_;
private OperandDef rowKey_;
private OperandDef superColumnKey_;
private int offset_;
private int limit_;
/**
* Set up a range query on super column map in a super column family.
* The super column map is identified by the rowKey.
*
* Note: "limit" of -1 is the equivalent of no limit.
* "offset" specifies the number of rows to skip.
* An offset of 0 implies from the first row.
*/
public SuperColumnRangeQueryRSD(CFMetaData cfMetaData, OperandDef rowKey, int offset, int limit)
{
cfMetaData_ = cfMetaData;
rowKey_ = rowKey;
offset_ = offset;
limit_ = limit;
}
public List<Map<String,String>> getRows()
{
Row row = null;
try
{
String key = (String)(rowKey_.get());
ReadCommand readCommand = new ReadCommand(cfMetaData_.tableName, key, cfMetaData_.cfName, offset_, limit_);
row = StorageProxy.readProtocol(readCommand, StorageService.ConsistencyLevel.WEAK);
}
catch (Exception e)
{
logger_.error(LogUtil.throwableToString(e));
throw new RuntimeException(RuntimeErrorMsg.GENERIC_ERROR.getMsg());
}
List<Map<String, String>> rows = new LinkedList<Map<String, String>>();
if (row != null)
{
Map<String, ColumnFamily> cfMap = row.getColumnFamilyMap();
if (cfMap != null && cfMap.size() > 0)
{
ColumnFamily cfamily = cfMap.get(cfMetaData_.cfName);
if (cfamily != null)
{
Collection<IColumn> columns = cfamily.getAllColumns();
if (columns != null && columns.size() > 0)
{
for (IColumn column : columns)
{
Collection<IColumn> subColumns = column.getSubColumns();
for( IColumn subColumn : subColumns )
{
Map<String, String> result = new HashMap<String, String>();
result.put(cfMetaData_.n_superColumnKey, column.name());
result.put(cfMetaData_.n_columnKey, subColumn.name());
result.put(cfMetaData_.n_columnValue, new String(subColumn.value()));
result.put(cfMetaData_.n_columnTimestamp, Long.toString(subColumn.timestamp()));
rows.add(result);
}
}
}
}
}
}
return rows;
}
public String explainPlan()
{
return String.format("%s Column Family: Super Column Range Query: \n" +
" Table Name: %s\n" +
" Column Family: %s\n" +
" RowKey: %s\n" +
" Offset: %d\n" +
" Limit: %d\n" +
" Order By: %s",
cfMetaData_.columnType,
cfMetaData_.tableName,
cfMetaData_.cfName,
rowKey_.explain(),
offset_, limit_,
cfMetaData_.indexProperty_);
}
}