IVSoftware.Portable.Reconciler 1.0.3

IVSoftware.Portable.Reconciler

Reconciler class encapsulates a static method to efficiently sort the two lists into five categories, using the sort and compare criteria supplied to the method.

Categories

• [OnlyInA] - Items that are only contained in the A collection.
• [OnlyInB] - Items that are only contained in the B collection.
• [NewerInA] - Items that are contained in both collections, where A has the newer time stamp.
• [NewerInB] - Items that are contained in both collections, where B has the newer time stamp.
• [Equal] - Returns a Tuple containing items whose sort criteria and time stamps are identical.

In the case of [Equal], we only know that the two objects are equal in terms of the supplied comparer delegates for UID and Version. This doesn't rule out the possibility that other properties could differ. Out of an abundance of caution, both versions are preserved and returned leaving it to the user's discretion whether or not to apply additional validation.

Method

/// <summary>
/// Static method to categorize two collections of items.
/// </summary>
/// <param name="srceA">An enumerable collection of T informally known as the A List.</param>
/// <param name="srceB">An enumerable collection of T informally known as the B List.</param>
/// <param name="uidSorter">A CompareUIDResult method that compares two T objects for sorting.</param>
/// <param name="versionComparer">A CompareVersionResult method that compares two T objects for <, >, == </param>
/// <param name="resultSorter">Optional Comparer T to return values in order.</param>
/// <returns>Reconciled T</returns>
/// <exception cref="NotImplementedException"></exception>
public static Reconciled<T> Reconcile<T>(
	IEnumerable<T> srceA, 
	IEnumerable<T> srceB, 
	Func<T, T, CompareUIDResult> uidSorter, 
	Func<T, T, CompareVersionResult> versionComparer,
	Func<T, T, int> resultSorter = null
);

Example class

class DatabaseRecord
{
    public object Guid { get;  }
        
    public DateTime TimeStamp { get; }

    // Other properties...
}

CompareUIDResult Example

Named delegate

The uidSorter sorts in ascending order. This argument can be passed by making a named method and passing 'just' the name:

CompareUIDResult CompareUID<DatabaseRecord>(a,b) => (CompareUIDResult)a.Guid.CompareTo(b.Guid);

In this case the argument would be uidSorter: CompareUID,

Anonymous delegate

It's usually easier to use an anonymous delegate and pass the method inline:

In this case the argument would be uidSorter: (a,b)=> (CompareUIDResult)a.Guid.CompareTo(b.Guid)

VersionComparer example

Named delegate

The versionComparer sorts in descending order. This argument can be passed by making a named method and passing 'just' the name:

CompareVersionResult CompareVersion<DatabaseRecord>(a,b) => (CompareVersionResult)a.TimeStamp.CompareTo(b.TimeStamp);

In this case the argument would be versionComparer: CompareUID,

Anonymous delegate

It's usually easier to use an anonymous delegate and pass the method inline:

In this case the argument would be versionComparer: (a,b)=> (CompareVersionResult)a.TimeStamp.CompareTo(b.TimeStamp)

Reconciled return class

Properties

/// <summary>
/// Items that are only contained in the A list.
/// </summary>
public T[] OnlyInA { get; }

/// <summary>
/// Items contained in both lists, where A has the newer time stamp.
/// </summary>
public T[] NewerInA { get; }

/// <summary>
/// Items that are only contained in the B list.
/// </summary>
public T[] OnlyInB { get; }

/// <summary>
/// Items contained in both lists, where B has the newer time stamp.
/// </summary>
public T[] NewerInB { get; }

/// <summary>
/// Items contained in both lists, whose sort criteria and time stamps are identical.
/// </summary>
public Tuple<T, T>[] Equal { get; }

/// <summary>
/// Detects whether the two lists are 'not' in sync.
/// </summary>
public bool HasChanges { get;}
			
/// <summary>
/// Using the item that 'is' newer as a key,
/// returns the item that 'is not' newer
/// </summary>
public Dictionary<T, T> Not { get; }

Method

/// <summary>
/// Verbose listing of the items in their categories.
/// </summary>
public override string ToString();