/**
* 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.ColumnReadCommand;
import org.apache.cassandra.db.IColumn;
import org.apache.cassandra.db.Row;
import org.apache.cassandra.db.ReadCommand;
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 looking up a unique column within a column family.
*/
public class UniqueKeyQueryRSD extends RowSourceDef
{
private final static Logger logger_ = Logger.getLogger(UniqueKeyQueryRSD.class);
private CFMetaData cfMetaData_;
private OperandDef rowKey_;
private OperandDef superColumnKey_;
private OperandDef columnKey_;
// super column family
public UniqueKeyQueryRSD(CFMetaData cfMetaData, OperandDef rowKey, OperandDef superColumnKey, OperandDef columnKey)
{
cfMetaData_ = cfMetaData;
rowKey_ = rowKey;
superColumnKey_ = superColumnKey;
columnKey_ = columnKey;
}
// simple column family
public UniqueKeyQueryRSD(CFMetaData cfMetaData, OperandDef rowKey, OperandDef columnKey)
{
cfMetaData_ = cfMetaData;
rowKey_ = rowKey;
columnKey_ = columnKey;
superColumnKey_ = null;
}
// specific column lookup
public List<Map<String,String>> getRows() throws RuntimeException
{
String columnKey = (String)(columnKey_.get());
String columnFamily_column;
String superColumnKey = null;
if (superColumnKey_ != null)
{
superColumnKey = (String)(superColumnKey_.get());
columnFamily_column = cfMetaData_.cfName + ":" + superColumnKey + ":" + columnKey;
}
else
{
columnFamily_column = cfMetaData_.cfName + ":" + columnKey;
}
Row row = null;
try
{
String key = (String)(rowKey_.get());
ReadCommand readCommand = new ColumnReadCommand(cfMetaData_.tableName, key, columnFamily_column);
row = StorageProxy.readProtocol(readCommand, StorageService.ConsistencyLevel.WEAK);
}
catch (Exception e)
{
logger_.error(LogUtil.throwableToString(e));
throw new RuntimeException(RuntimeErrorMsg.GENERIC_ERROR.getMsg());
}
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 = null;
if (superColumnKey_ != null)
{
// this is the super column case
IColumn column = cfamily.getColumn(superColumnKey);
if (column != null)
columns = column.getSubColumns();
}
else
{
columns = cfamily.getAllColumns();
}
if (columns != null && columns.size() > 0)
{
if (columns.size() > 1)
{
// We are looking up by a rowKey & columnKey. There should
// be at most one column that matches. If we find more than
// one, then it is an internal error.
throw new RuntimeException(RuntimeErrorMsg.INTERNAL_ERROR.getMsg("Too many columns found for: " + columnKey));
}
for (IColumn column : columns)
{
List<Map<String, String>> rows = new LinkedList<Map<String, String>>();
Map<String, String> result = new HashMap<String, String>();
result.put(cfMetaData_.n_columnKey, column.name());
result.put(cfMetaData_.n_columnValue, new String(column.value()));
result.put(cfMetaData_.n_columnTimestamp, Long.toString(column.timestamp()));
rows.add(result);
// at this point, due to the prior checks, we are guaranteed that
// there is only one item in "columns".
return rows;
}
return null;
}
}
}
}
throw new RuntimeException(RuntimeErrorMsg.NO_DATA_FOUND.getMsg());
}
public String explainPlan()
{
return String.format("%s Column Family: Unique Key Query: \n" +
" Table Name: %s\n" +
" Column Famly: %s\n" +
" RowKey: %s\n" +
"%s" +
" ColumnKey: %s",
cfMetaData_.columnType,
cfMetaData_.tableName,
cfMetaData_.cfName,
rowKey_.explain(),
(superColumnKey_ == null) ? "" : " SuperColumnKey: " + superColumnKey_.explain() + "\n",
columnKey_.explain());
}
}