private void SetRequester()
{
var generator = new ExpressionGenerator(_tableDescription, IndexName, QueryInfo.WhereExpression);
var generateResult = generator.Analyze();
var sortKeyExists = !string.IsNullOrEmpty(generator.SortKeyName);
// Hash key only in this index
if (!sortKeyExists)
{
// If HashKey not found in where expr
if (generateResult.HashKey == null)
{
_requester = new ScanRequester();
}
else
{
if (string.IsNullOrEmpty(IndexName) && string.IsNullOrWhiteSpace(generateResult.FilterExpression))
{
_requester = new GetItemRequester();
}
else
{
_requester = new QueryRequester();
}
}
}
// HashKey and SortKey
else
{
// If HashKey or SortKey not found in where expr
if (generateResult.HashKey == null &&
generateResult.SortKey == null)
{
_requester = new ScanRequester();
}
else
{
if (string.IsNullOrEmpty(IndexName) &&
string.IsNullOrWhiteSpace(generateResult.FilterExpression) &&
generateResult.SortKey?.Operator == "=")
{
_requester = new GetItemRequester();
}
else
{
_requester = new QueryRequester();
}
}
}
_requester.Command = Command;
_requester.SetParameters(
Context.Client,
QueryInfo,
generateResult.ExpressionAttributeNames,
generateResult.ExpressionAttributeValues,
generateResult.HashKey,
generateResult.SortKey,
generator.HashKeyName,
generator.SortKeyName,
TableName,
IndexName,
generateResult.FilterExpression
);
}