/// <summary>
/// 시퀀스로부터, 조건에 맞는 요소만을 필터링을 수행합니다.
/// </summary>
/// <typeparam name="TSource"></typeparam>
/// <param name="sourceCollection"></param>
/// <param name="expr"></param>
/// <returns></returns>
public static IEnumerable <TSource> Where <TSource>(this IndexableCollection <TSource> sourceCollection,
Expression <Func <TSource, bool> > expr)
{
sourceCollection.ShouldNotBeNull("sourceCollection");
expr.ShouldNotBeNull("expr");
var noIndex = true;
if (expr.Body.NodeType == ExpressionType.Equal)
{
// Equality is a binary expression
BinaryExpression binaryExpr = (BinaryExpression)expr.Body;
// Get aliases for both side
Expression leftSide = binaryExpr.Left;
Expression rightSide = binaryExpr.Right;
var hashRight = GetHashRight(leftSide, rightSide);
MemberExpression returnExpr;
if (hashRight.HasValue && HasIndexablePropertyOnLeft(leftSide, sourceCollection, out returnExpr))
{
// cast to MemberExpression = it allows us to get the property
var propertyExpr = returnExpr;
var propertyName = propertyExpr.Member.Name;
var sourceIndex = sourceCollection.GetIndexByProperty(propertyName);
if (sourceIndex.ContainsKey(hashRight.Value))
{
var sourceEnum = sourceIndex[hashRight.Value].AsEnumerable();
var results = sourceEnum.Where(expr.Compile());
foreach (var resultItem in results)
{
yield return(resultItem);
}
}
noIndex = false;
}
}
// 지정된 시퀀스에 인덱스가 없다면...
if (noIndex)
{
if (IsDebugEnabled)
{
log.Debug("Index가 없으므로 System.Linq.Enumerable.Where()을 수행합니다. ");
}
var sourceEnum = sourceCollection.AsEnumerable();
var results = sourceEnum.Where(expr.Compile());
foreach (var resultItem in results)
{
yield return(resultItem);
}
}
}
/// <summary>
/// 인덱싱된 시퀀스에서 일치하는 키를 기준으로 두 시퀀스의 요소를 연관시킵니다. 지정한 IEqualityComparer{TKey}를 사용하여 키를 비교합니다.
/// </summary>
public static IEnumerable <TResult> Join <TOuter, TInner, TKey, TResult>(
this IndexableCollection <TOuter> outer,
IndexableCollection <TInner> inner,
Expression <Func <TOuter, TKey> > outerKeySelector,
Expression <Func <TInner, TKey> > innerKeySelector,
Func <TOuter, TInner, TResult> resultSelector,
IEqualityComparer <TKey> comparer)
{
outer.ShouldNotBeNull("outer");
inner.ShouldNotBeNull("inner");
outerKeySelector.ShouldNotBeNull("outerKeySelector");
innerKeySelector.ShouldNotBeNull("innerKeySelector");
resultSelector.ShouldNotBeNull("resultSelector");
bool hasIndex = false;
if (innerKeySelector.NodeType == ExpressionType.Lambda &&
innerKeySelector.Body.NodeType == ExpressionType.MemberAccess &&
outerKeySelector.NodeType == ExpressionType.Lambda &&
outerKeySelector.Body.NodeType == ExpressionType.MemberAccess)
{
var memberExpressionInner = (MemberExpression)innerKeySelector.Body;
var memberExpressionOuter = (MemberExpression)outerKeySelector.Body;
var innerIndex = new MultiMap <int, TInner>();
var outerIndex = new MultiMap <int, TOuter>();
if (inner.PropertyHasIndex(memberExpressionInner.Member.Name) &&
outer.PropertyHasIndex(memberExpressionOuter.Member.Name))
{
innerIndex = inner.GetIndexByProperty(memberExpressionInner.Member.Name);
outerIndex = outer.GetIndexByProperty(memberExpressionOuter.Member.Name);
hasIndex = true;
}
if (hasIndex)
{
foreach (int outerKey in outerIndex.Keys)
{
IList <TOuter> outerGroup = outerIndex[outerKey];
IList <TInner> innerGroup;
if (innerIndex.TryGetValue(outerKey, out innerGroup))
{
// join on the GROUPS based on key result
IEnumerable <TInner> inners = innerGroup.AsEnumerable();
IEnumerable <TOuter> outers = outerGroup.AsEnumerable();
IEnumerable <TResult> results = outers.Join(inners, outerKeySelector.Compile(),
innerKeySelector.Compile(),
resultSelector, comparer);
foreach (TResult resultItem in results)
{
yield return(resultItem);
}
}
}
}
}
if (hasIndex == false)
{
if (IsDebugEnabled)
{
log.Debug("Index가 없으므로 System.Linq.Enumerable.Join()을 수행합니다. ");
}
var inners = inner.AsEnumerable();
var outers = outer.AsEnumerable();
var results = outers.Join(inners, outerKeySelector.Compile(),
innerKeySelector.Compile(),
resultSelector, comparer);
foreach (var resultItem in results)
{
yield return(resultItem);
}
}
}