IEntryDecoration

IEntryDecoration indicates that entry is a decoration of another entry.

/// <summary>Decorated <see cref="IEntry"/> that contains a value that is derived of other source.</summary>
public interface IEntryDecoration : IEntry
{
    /// <summary>Determines dispose behaviour of <see cref="Source"/>. If set to true, <see cref="Source"/> is disposed along with decoration</summary>
    bool DisposeUnderlying { get; set; }
    /// <summary>The underlying source <see cref="IEntry"/> of this decoration is derived of.</summary>
    IEntry? Source { get; }
}

IEntryDecorator decorates a entry in some specific way.

/// <summary>Decorates <see cref="IEntry"/>s in an unspecified way.</summary>
public interface IEntryDecorator
{
    /// <summary>Decorate <paramref name="entry"/></summary>
    /// <param name="entry"></param>
    /// <returns>Decorated version of <paramref name="entry"/>. May or may not implement <see cref="IEntryDecoration"/>.</returns>
    IEntry Decorate(IEntry entry);
}

Decorator applies a decoration to a entry.

// Create entry
IEntry entry = new Entry<string>();
// Create decorator
IEntryDecorator decorator = new LoggingDecorator(Console.Out);
// Decorate entry to log 
entry = decorator.Decorate(entry);
// Assign value
entry.SetValue("Value");

public class LoggingDecorator : IEntryDecorator
{
    static ConstructorT<IEntry, TextWriter, IEntry> ctor = new(typeof(LoggingDecoration<>));
    TextWriter writer;
    public LoggingDecorator(TextWriter writer) => this.writer = writer;

    public IEntry Decorate(IEntry entry)
    {
        StructList2<Type> types = ((IEntryReadable)entry).ValueTypes<StructList2<Type>>();
        IEntry decoration = ctor.Create(types[0], entry, writer);
        return decoration;
    }
}

public class LoggingDecoration<T> : EntryDecoration<T>
{
    TextWriter writer;

    public LoggingDecoration(IEntry source, TextWriter writer) : base(source, true)
    {
        this.source = source;
        this.writer = writer;
    }

    public override bool TrySetValue(object? value)
    {
        writer.WriteLine(value);
        return base.TrySetValue(value);
    }
}

Full Example

Full example

using System;
using System.IO;
using Avalanche.Service;
using Avalanche.Utilities;

public class entry_decoration
{
    public static void Run()
    {
        {
            // <01>
            // Create entry
            IEntry entry = new Entry<string>();
            // Create decorator
            IEntryDecorator decorator = new LoggingDecorator(Console.Out);
            // Decorate entry to log 
            entry = decorator.Decorate(entry);
            // Assign value
            entry.SetValue("Value");
            // </01>
        }
    }

    // <98>
    public class LoggingDecorator : IEntryDecorator
    {
        static ConstructorT<IEntry, TextWriter, IEntry> ctor = new(typeof(LoggingDecoration<>));
        TextWriter writer;
        public LoggingDecorator(TextWriter writer) => this.writer = writer;

        public IEntry Decorate(IEntry entry)
        {
            StructList2<Type> types = ((IEntryReadable)entry).ValueTypes<StructList2<Type>>();
            IEntry decoration = ctor.Create(types[0], entry, writer);
            return decoration;
        }
    }
    // </98>

    // <99>
    public class LoggingDecoration<T> : EntryDecoration<T>
    {
        TextWriter writer;

        public LoggingDecoration(IEntry source, TextWriter writer) : base(source, true)
        {
            this.source = source;
            this.writer = writer;
        }

        public override bool TrySetValue(object? value)
        {
            writer.WriteLine(value);
            return base.TrySetValue(value);
        }
    }
    // </99>
}