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Jazz Up Your C# Code

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3 Jul 2012CPOL28 min read 51.6K   369   54  
Maintaining code with complex permissions tends to be difficult, because the code can be distributed across multiple classes. By embedding permissions directly on methods and properties within a class, code is reduced and maintainability is simplified.
/*
 Copyright (c) 2003-2006 Niels Kokholm and Peter Sestoft
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:
 
 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
*/

using System;
using System.Text;

namespace C5
{
    /// <summary>
    /// <i>(Describe usage of "L:300" format string.)</i>
    /// </summary>
    public interface IShowable : IFormattable
    {
        //TODO: wonder if we should use TextWriters instead of StringBuilders?
        /// <summary>
        /// Format <code>this</code> using at most approximately <code>rest</code> chars and 
        /// append the result, possibly truncated, to stringbuilder.
        /// Subtract the actual number of used chars from <code>rest</code>.
        /// </summary>
        /// <param name="stringbuilder"></param>
        /// <param name="rest"></param>
        /// <param name="formatProvider"></param>
        /// <returns>True if the appended formatted string was complete (not truncated).</returns>
        bool Show(StringBuilder stringbuilder, ref int rest, IFormatProvider formatProvider);
    }
    // ------------------------------------------------------------

    // Static helper methods for Showing collections 

    /// <summary>
    /// 
    /// </summary>
    public static class Showing
    {
        /// <summary>
        /// Show  <code>Object obj</code> by appending it to <code>stringbuilder</code>
        /// </summary>
        /// <param name="obj"></param>
        /// <param name="stringbuilder"></param>
        /// <param name="rest"></param>
        /// <param name="formatProvider"></param>
        /// <returns>True if <code>obj</code> was shown completely.</returns>
        public static bool Show(Object obj, StringBuilder stringbuilder, ref int rest, IFormatProvider formatProvider)
        {
            IShowable showable;
            if (rest <= 0)
                return false;
            else if ((showable = obj as IShowable) != null)
                return showable.Show(stringbuilder, ref rest, formatProvider);
            int oldLength = stringbuilder.Length;
            stringbuilder.AppendFormat(formatProvider, "{0}", obj);
            rest -= (stringbuilder.Length - oldLength);
            return true;
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="showable"></param>
        /// <param name="format"></param>
        /// <param name="formatProvider"></param>
        /// <returns></returns>
        public static String ShowString(IShowable showable, String format, IFormatProvider formatProvider)
        {
            int rest = maxLength(format);
            StringBuilder sb = new StringBuilder();
            showable.Show(sb, ref rest, formatProvider);
            return sb.ToString();
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="format"></param>
        /// <returns></returns>
        static int maxLength(String format)
        {
            //TODO: validate format string
            if (format == null)
                return 80;
            if (format.Length > 1 && format.StartsWith("L"))
            {
                return int.Parse(format.Substring(1));
            }
            else
                return int.MaxValue;
        }

        /// <summary>
        /// 
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="items"></param>
        /// <param name="stringbuilder"></param>
        /// <param name="rest"></param>
        /// <param name="formatProvider"></param>
        /// <returns>True if collection was shown completely</returns>
        public static bool ShowCollectionValue<T>(ICollectionValue<T> items, StringBuilder stringbuilder, ref int rest, IFormatProvider formatProvider)
        {
            string startdelim = "{ ", enddelim = " }";
            bool showIndexes = false;
            bool showMultiplicities = false;
            //TODO: do not test here at run time, but select code at compile time
            //      perhaps by delivering the print type to this metod
            IList<T> list;
            ICollection<T> coll = items as ICollection<T>;
            if ((list = items as IList<T>) != null)
            {
                startdelim = "[ ";
                enddelim = " ]";
                //TODO: should have been (items as IIndexed<T>).IndexingSpeed
                showIndexes = list.IndexingSpeed == Speed.Constant;
            }
            else if (coll != null)
            {
                if (coll.AllowsDuplicates)
                {
                    startdelim = "{{ ";
                    enddelim = " }}";
                    if (coll.DuplicatesByCounting)
                        showMultiplicities = true;
                }
            }

            stringbuilder.Append(startdelim);
            rest -= 2 * startdelim.Length;
            bool first = true;
            bool complete = true;
            int index = 0;

            if (showMultiplicities)
            {
                foreach (KeyValuePair<T, int> p in coll.ItemMultiplicities())
                {
                    complete = false;
                    if (rest <= 0)
                        break;
                    if (first)
                        first = false;
                    else
                    {
                        stringbuilder.Append(", ");
                        rest -= 2;
                    }
                    if (complete = Showing.Show(p.Key, stringbuilder, ref rest, formatProvider))
                    {
                        string multiplicityString = string.Format("(*{0})", p.Value);
                        stringbuilder.Append(multiplicityString);
                        rest -= multiplicityString.Length;
                    }
                }
            }
            else
            {
                foreach (T x in items)
                {
                    complete = false;
                    if (rest <= 0)
                        break;
                    if (first)
                        first = false;
                    else
                    {
                        stringbuilder.Append(", ");
                        rest -= 2;
                    }
                    if (showIndexes)
                    {
                        string indexString = string.Format("{0}:", index++);
                        stringbuilder.Append(indexString);
                        rest -= indexString.Length;
                    }
                    complete = Showing.Show(x, stringbuilder, ref rest, formatProvider);
                }
            }
            if (!complete)
            {
                stringbuilder.Append("...");
                rest -= 3;
            }
            stringbuilder.Append(enddelim);
            return complete;
        }

        /// <summary>
        /// 
        /// </summary>
        /// <typeparam name="K"></typeparam>
        /// <typeparam name="V"></typeparam>
        /// 
        /// <param name="dictionary"></param>
        /// <param name="stringbuilder"></param>
        /// <param name="formatProvider"></param>
        /// <param name="rest"></param>
        /// <returns></returns>
        public static bool ShowDictionary<K, V>(IDictionary<K, V> dictionary, StringBuilder stringbuilder, ref int rest, IFormatProvider formatProvider)
        {
            bool sorted = dictionary is ISortedDictionary<K, V>;
            stringbuilder.Append(sorted ? "[ " : "{ ");
            rest -= 4;				   // Account for "( " and " )"
            bool first = true;
            bool complete = true;

            foreach (KeyValuePair<K, V> p in dictionary)
            {
                complete = false;
                if (rest <= 0)
                    break;
                if (first)
                    first = false;
                else
                {
                    stringbuilder.Append(", ");
                    rest -= 2;
                }
                complete = Showing.Show(p, stringbuilder, ref rest, formatProvider);
            }
            if (!complete)
            {
                stringbuilder.Append("...");
                rest -= 3;
            }
            stringbuilder.Append(sorted ? " ]" : " }");
            return complete;
        }
    }
}

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License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


Written By
Web Developer TrackerRealm
Canada Canada
Charles Wiebe and John Hansen are Microsoft .NET software architect/designer, for Windows Forms and ASP.NET solutions.
Charles specializes in the application layer – Web Parts and other ways of building GUI’s. John specializes in high capacity object oriented systems and connectivity.

John and Charles are co-developers of Jetfire – a .net open source, multi-user, application domain specific language (DSL) with syntax heavily based on C# and Java. The goal of Jetfire is to allow power users to quickly and easily develop and deploy applications, in much the same way as Excel allows powers users to quickly develop spread sheets.

Their latest project is Jazz - a compact, modular framework that allows new, or existing, applications to easily employ roles, states, ACLs and void safety. Jazz allows complete workflows to be implemented in only a few hundred lines of C# or VB code.

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