/*
* 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.geode.redis.internal.executor.list;
import java.util.List;
import org.apache.geode.cache.Region;
import org.apache.geode.cache.query.Query;
import org.apache.geode.cache.query.SelectResults;
import org.apache.geode.cache.query.Struct;
import org.apache.geode.redis.internal.ByteArrayWrapper;
import org.apache.geode.redis.internal.Coder;
import org.apache.geode.redis.internal.Command;
import org.apache.geode.redis.internal.ExecutionHandlerContext;
import org.apache.geode.redis.internal.RedisConstants.ArityDef;
import org.apache.geode.redis.internal.RedisDataType;
import org.apache.geode.redis.internal.executor.ListQuery;
public class LIndexExecutor extends ListExecutor {
private final String ERROR_NOT_NUMERIC = "The index provided is not numeric";
@Override
public void executeCommand(Command command, ExecutionHandlerContext context) {
List<byte[]> commandElems = command.getProcessedCommand();
if (commandElems.size() < 3) {
command.setResponse(Coder.getErrorResponse(context.getByteBufAllocator(), ArityDef.LINDEX));
return;
}
ByteArrayWrapper key = command.getKey();
byte[] indexArray = commandElems.get(2);
checkDataType(key, RedisDataType.REDIS_LIST, context);
Region<Integer, ByteArrayWrapper> keyRegion = getRegion(context, key);
if (keyRegion == null) {
command.setResponse(Coder.getNilResponse(context.getByteBufAllocator()));
return;
}
int listSize = keyRegion.size() - LIST_EMPTY_SIZE;
Integer redisIndex;
try {
redisIndex = Coder.bytesToInt(indexArray);
} catch (NumberFormatException e) {
command.setResponse(Coder.getErrorResponse(context.getByteBufAllocator(), ERROR_NOT_NUMERIC));
return;
}
/*
* Now the fun part, converting the redis index into our index. The redis index is 0 based but
* negative values count from the tail
*/
if (redisIndex < 0)
// Since the redisIndex is negative here, this will reset it to be a standard 0 based index
redisIndex = listSize + redisIndex;
/*
* If the index is still less than 0 that means the index has shot off back past the beginning,
* which means the index isn't real and a nil is returned
*/
if (redisIndex < 0) {
command.setResponse(Coder.getNilResponse(context.getByteBufAllocator()));
return;
}
/*
* Now we must get that element from the region
*/
Struct entry;
try {
entry = getEntryAtIndex(context, key, redisIndex);
} catch (Exception e) {
throw new RuntimeException(e);
}
if (entry == null) {
command.setResponse(Coder.getNilResponse(context.getByteBufAllocator()));
return;
}
Object[] entryArray = entry.getFieldValues();
ByteArrayWrapper valueWrapper = (ByteArrayWrapper) entryArray[1];
command.setResponse(
Coder.getBulkStringResponse(context.getByteBufAllocator(), valueWrapper.toBytes()));
}
private Struct getEntryAtIndex(ExecutionHandlerContext context, ByteArrayWrapper key, int index)
throws Exception {
Query query = getQuery(key, ListQuery.LINDEX, context);
Object[] params = {Integer.valueOf(index + 1)};
SelectResults<?> results = (SelectResults<?>) query.execute(params);
if (results == null || results.size() == 0 || results.size() <= index)
return null;
else
return (Struct) results.asList().get(index);
}
}