/// <summary>
/// Gets the aggregate value, by grouping, of the values in the given entity field.
/// </summary>
/// <returns>The sum of the values of the given property name for the entities in the <see cref="DataStore{T}"/>.</returns>
/// <param name="groupField">Property name of field to be used in grouping.</param>
/// <param name="aggregateField">Property name of field to be used in aggregation. This is not necessary when using the <see cref="KinveyXamarin.EnumReduceFunction.REDUCE_FUNCTION_COUNT"/> method.</param>
/// <param name="query">[optional] Query used to filter results prior to aggregation.</param>
/// <param name="cacheDelegate">Delegate used to return the sum aggregate value based on what is available in offline cache.</param>
/// <param name="ct">[optional] CancellationToken used to cancel the request.</param>
public async Task <List <GroupAggregationResults> > GroupAndAggregateAsync(EnumReduceFunction reduceFunction, string groupField = "", string aggregateField = "", IQueryable <object> query = null, KinveyDelegate <List <GroupAggregationResults> > cacheDelegate = null, CancellationToken ct = default(CancellationToken))
{
FindAggregateRequest <T> findByAggregateQueryRequest = new FindAggregateRequest <T>(client, collectionName, reduceFunction, cache, storeType.ReadPolicy, DeltaSetFetchingEnabled, cacheDelegate, query, groupField, aggregateField);
ct.ThrowIfCancellationRequested();
return(await findByAggregateQueryRequest.ExecuteAsync());
}
/// <summary>
/// Initializes a new instance of the <see cref="T:KinveyXamarin.FindAggregateRequest`1"/> class.
/// </summary>
/// <param name="client">Client.</param>
/// <param name="collection">Collection.</param>
/// <param name="reduceFunction">Reduce function.</param>
/// <param name="cache">Cache.</param>
/// <param name="policy"> The <see cref="ReadPolicy"/> to be used for this request.</param>
/// <param name="deltaSetFetchingEnabled">If set to <c>true</c> delta set fetching enabled.</param>
/// <param name="cacheDelegate">Cache delegate.</param>
/// <param name="query">[optional] Query used to filter the results that are to be aggregated.</param>
/// <param name="groupField">Property name to be used for grouping.</param>
/// <param name="aggregateField">Property name to be used for aggregation.</param>
public FindAggregateRequest(AbstractClient client,
string collection,
EnumReduceFunction reduceFunction,
ICache <T> cache,
ReadPolicy policy,
bool deltaSetFetchingEnabled,
KinveyDelegate <List <GroupAggregationResults> > cacheDelegate,
IQueryable <object> query,
string groupField,
string aggregateField)
: base(client, collection, cache, query, policy, deltaSetFetchingEnabled)
{
this.cacheDelegate = cacheDelegate;
this.reduceFunction = reduceFunction;
this.groupField = groupField;
this.aggregateField = aggregateField;
}
public NetworkRequest <T> BuildGetAggregateRequest <T>(string collectionName, EnumReduceFunction reduceFunction, string query, string groupField, string aggregateField)
{
string REST_PATH = "appdata/{appKey}/{collectionName}/_group";
var urlParameters = new Dictionary <string, string>();
urlParameters.Add("appKey", ((KinveyClientRequestInitializer)client.RequestInitializer).AppKey);
urlParameters.Add("collectionName", collectionName);
JObject keyval = new JObject();
if (!String.IsNullOrEmpty(groupField))
{
keyval.Add(groupField, true);
}
JObject initialval = new JObject();
JObject httpBodyContent = new JObject();
httpBodyContent.Add("key", keyval);
string reduce = String.Empty;
switch (reduceFunction)
{
case EnumReduceFunction.REDUCE_FUNCTION_SUM:
initialval.Add("result", 0);
reduce = $"function(doc,out){{ out.result += doc.{aggregateField}; }}";
break;
case EnumReduceFunction.REDUCE_FUNCTION_MIN:
initialval.Add("result", Int32.MaxValue);
reduce = $"function(doc,out){{ out.result = Math.min(out.result, doc.{aggregateField}); }}";
break;
case EnumReduceFunction.REDUCE_FUNCTION_MAX:
initialval.Add("result", Int32.MinValue);
reduce = $"function(doc,out){{ out.result = Math.max(out.result, doc.{aggregateField}); }}";
break;
case EnumReduceFunction.REDUCE_FUNCTION_AVERAGE:
initialval.Add("result", 0);
initialval.Add("count", 0);
reduce = $"function(doc,out){{ out.result = (((out.result * out.count) + doc.{aggregateField}) / (out.count += 1)); }}";
break;
default:
// TODO throw new KinveyException()
break;
}
httpBodyContent.Add("initial", initialval);
httpBodyContent.Add("reduce", reduce);
if (!String.IsNullOrEmpty(query))
{
const char CHAR_CURLY_BRACE_OPENING = '{';
const char CHAR_CURLY_BRACE_CLOSING = '}';
const char CHAR_COLON = ':';
const char CHAR_DOUBLE_QUOTATION_MARK = '"';
JObject condition = new JObject();
query = query.TrimStart(CHAR_CURLY_BRACE_OPENING).TrimEnd(CHAR_CURLY_BRACE_CLOSING);
string[] cond = query.Split(CHAR_COLON);
cond[0] = cond[0].TrimStart(CHAR_DOUBLE_QUOTATION_MARK).TrimEnd(CHAR_DOUBLE_QUOTATION_MARK);
cond[1] = cond[1].TrimStart(CHAR_DOUBLE_QUOTATION_MARK).TrimEnd(CHAR_DOUBLE_QUOTATION_MARK);
condition.Add(cond[0], cond[1]);
httpBodyContent.Add("condition", condition);
}
NetworkRequest <T> findAggregateQuery = new NetworkRequest <T>(client, "POST", REST_PATH, httpBodyContent, urlParameters);
client.InitializeRequest(findAggregateQuery);
return(findAggregateQuery);
}
public List <GroupAggregationResults> GetAggregateResult(EnumReduceFunction reduceFunction, string groupField, string aggregateField, Expression query)
{
List <GroupAggregationResults> localAggregateResults = new List <GroupAggregationResults>();
List <object> listValues = new List <object>();
PropertyInfo propInfo = typeof(T).GetRuntimeProperty(aggregateField);
if (propInfo != null &&
IsTypeNumber(propInfo.PropertyType))
{
int skipNumber = 0;
int takeNumber = 0;
bool sort = false;
LambdaExpression exprSort = null;
var lambdaExpr = ConvertQueryExpressionToFunction(query, ref skipNumber, ref takeNumber, ref sort, ref exprSort);
if (String.IsNullOrEmpty(groupField))
{
// Not grouping results be a specified field, so just aggregate over all entities
// that pass through the query filter, if provided.
GroupAggregationResults gar = new GroupAggregationResults();
gar.GroupField = null;
// TODO do "skip" and "take" have to be taken into account in group aggregate functions?
if (lambdaExpr != null)
{
listValues = (from t in dbConnectionSync.Table <T>().Where(lambdaExpr) select t.GetType().GetRuntimeProperty(aggregateField).GetValue(t, null)).ToList();
}
else
{
listValues = (from t in dbConnectionSync.Table <T>() select t.GetType().GetRuntimeProperty(aggregateField).GetValue(t, null)).ToList();
}
switch (reduceFunction)
{
case EnumReduceFunction.REDUCE_FUNCTION_SUM:
foreach (int val in listValues)
{
gar.Result += val;
}
break;
case EnumReduceFunction.REDUCE_FUNCTION_MIN:
gar.Result = int.MaxValue;
foreach (int val in listValues)
{
gar.Result = Math.Min(gar.Result, val);
}
break;
case EnumReduceFunction.REDUCE_FUNCTION_MAX:
gar.Result = int.MinValue;
foreach (int val in listValues)
{
gar.Result = Math.Max(gar.Result, val);
}
break;
case EnumReduceFunction.REDUCE_FUNCTION_AVERAGE:
int count = 0;
int total = 0;
foreach (int val in listValues)
{
total += val;
count++;
}
gar.Result = total / count;
break;
default:
// TODO throw new KinveyException
break;
}
localAggregateResults.Add(gar);
}
else
{
// A grouping field was supplied, so aggregate
// result per group created on the group field
IEnumerable <IGrouping <object, T> > grouplist;
if (lambdaExpr != null)
{
grouplist = from t in dbConnectionSync.Table <T>().Where(lambdaExpr)
group t by t.GetType().GetRuntimeProperty(groupField).GetValue(t, null);
}
else
{
grouplist = from t in dbConnectionSync.Table <T>()
group t by t.GetType().GetRuntimeProperty(groupField).GetValue(t, null);
}
foreach (var grouping in grouplist)
{
int result = 0;
listValues = (from x in grouping select x.GetType().GetRuntimeProperty(aggregateField).GetValue(x, null)).ToList();
GroupAggregationResults gar = new GroupAggregationResults();
gar.GroupField = grouping.Key.ToString();
switch (reduceFunction)
{
case EnumReduceFunction.REDUCE_FUNCTION_SUM:
foreach (int val in listValues)
{
result += val;
}
break;
case EnumReduceFunction.REDUCE_FUNCTION_MIN:
result = int.MaxValue;
foreach (int val in listValues)
{
result = Math.Min(result, val);
}
break;
case EnumReduceFunction.REDUCE_FUNCTION_MAX:
result = int.MinValue;
foreach (int val in listValues)
{
result = Math.Max(result, val);
}
break;
case EnumReduceFunction.REDUCE_FUNCTION_AVERAGE:
int count = 0;
int total = 0;
foreach (int val in listValues)
{
total += val;
count++;
}
result = total / count;
break;
default:
// TODO throw new KinveyException
break;
}
gar.Result = result;
localAggregateResults.Add(gar);
}
}
}
return(localAggregateResults);
}
