ExpandSegment.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataWeb / Server / System / Data / Services / ExpandSegment.cs / 1407647 / ExpandSegment.cs
                        
                        
                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//  
//      Provides a description of a segment in an $expand query option
//      for a WCF Data Service. 
//  
//
// @owner  [....] 
//---------------------------------------------------------------------

namespace System.Data.Services
{ 
    #region Namespaces.
 
    using System; 
    using System.Collections.Generic;
    using System.Data.Services.Providers; 
    using System.Diagnostics;
    using System.Linq.Expressions;

    #endregion Namespaces. 

    ///  
    /// Provides a description of a segment in an $expand query option for a WCF Data Service. 
    /// 
    ///  
    /// INTERNAL
    /// Expand providers may replace segments to indicate a different expansion shape. However, they are
    /// unable to set the MaxResultsExpected. The value for the instances created by external providers
    /// will always be Int32.MaxValue, but the value enforced by the serializers will be the one declared 
    /// by the data service in the configuration.
    /// 
    /// When the configuration supports a more granular value, we should overload the constructor to make 
    /// the MaxResultsExpected property settable as well.
    ///  
    [DebuggerDisplay("ExpandSegment ({name},Filter={filter})]")]
    public class ExpandSegment
    {
        #region Private fields. 

        /// Container to which the segment belongs; possibly null. 
        private readonly ResourceSetWrapper container; 

        /// Filter expression for this segment on an $expand path. 
        private readonly Expression filter;

        /// Name for this segment on an $expand path.
        private readonly string name; 

        /// Property being expanded. 
        private readonly ResourceProperty expandedProperty; 

        ///  
        /// The maximum number of results expected for this property; Int32.MaxValue if no limit is expected.
        /// 
        private readonly int maxResultsExpected;
 
        /// Collection of ordering information for this segment, used for paging
        private readonly OrderingInfo orderingInfo; 
 
        #endregion Private fields.
 
        #region Constructors.

        /// Initializes a new  instance.
        /// Segment name. 
        /// Filter expression for segment, possibly null.
        public ExpandSegment(string name, Expression filter) 
            : this(name, filter, Int32.MaxValue, null, null, null) 
        {
        } 

        /// Initializes a new  instance.
        /// Segment name.
        /// Filter expression for segment, possibly null. 
        /// 
        /// Expand providers may choose to return at most MaxResultsExpected + 1 elements to allow the 
        /// data service to detect a failure to meet this constraint. 
        /// 
        /// Container to which the segment belongs; possibly null. 
        /// Property expanded by this expand segment
        /// Collection of ordering information for this segment, used for paging
        internal ExpandSegment(
            string name, 
            Expression filter,
            int maxResultsExpected, 
            ResourceSetWrapper container, 
            ResourceProperty expandedProperty,
            OrderingInfo orderingInfo) 
        {
            WebUtil.CheckArgumentNull(name, "name");
            CheckFilterType(filter);
            this.name = name; 
            this.filter = filter;
            this.container = container; 
            this.maxResultsExpected = maxResultsExpected; 
            this.expandedProperty = expandedProperty;
            this.orderingInfo = orderingInfo; 
        }

        #endregion Constructors.
 
        #region Public properties.
 
        /// Filter expression for this segment on an $expand path. 
        public Expression Filter
        { 
            get { return this.filter; }
        }

        /// Whether this segment has a filter. 
        public bool HasFilter
        { 
            get { return this.Filter != null; } 
        }
 
        /// 
        /// The maximum number of results expected for this property; Int32.MaxValue if no limit is expected.
        /// 
        ///  
        /// Expand providers may choose to return at most MaxResultsExpected + 1 elements to allow the
        /// data service to detect a failure to meet this constraint. 
        ///  
        public int MaxResultsExpected
        { 
            get { return this.maxResultsExpected; }
        }

        /// Name for this segment on an $expand path. 
        public string Name
        { 
            get { return this.name; } 
        }
 
        /// Property being expanded.
        public ResourceProperty ExpandedProperty
        {
            get { return this.expandedProperty; } 
        }
 
        /// Collection of ordering information for this segment, used for paging 
        internal OrderingInfo OrderingInfo
        { 
            get
            {
                return this.orderingInfo;
            } 
        }
 
        #endregion Public properties. 

        #region Internal properties. 

        /// Gets the container to which this segment belongs; possibly null.
        internal ResourceSetWrapper Container
        { 
            get { return this.container; }
        } 
 
        #endregion Internal properties.
 
        #region Public methods.

        /// Checks whether any segments in the specified  have a filter.
        /// Path with segments to check. 
        /// true if any of the segments in  has a filter; false otherwise.
        public static bool PathHasFilter(IEnumerable path) 
        { 
            WebUtil.CheckArgumentNull(path, "path");
            foreach (ExpandSegment segment in path) 
            {
                if (segment.HasFilter)
                {
                    return true; 
                }
            } 
 
            return false;
        } 

        #endregion Public methods.

        #region Private methods. 

        /// Checks that the specified filter is of the right type. 
        /// Filter to check. 
        private static void CheckFilterType(Expression filter)
        { 
            if (filter == null)
            {
                return;
            } 

            if (filter.NodeType != ExpressionType.Lambda) 
            { 
                throw new ArgumentException(Strings.ExpandSegment_FilterShouldBeLambda(filter.NodeType), "filter");
            } 

            LambdaExpression lambda = (LambdaExpression)filter;
            if (lambda.Body.Type != typeof(bool) && lambda.Body.Type != typeof(bool?))
            { 
                throw new ArgumentException(
                    Strings.ExpandSegment_FilterBodyShouldReturnBool(lambda.Body.Type), "filter"); 
            } 

            if (lambda.Parameters.Count != 1) 
            {
                throw new ArgumentException(
                    Strings.ExpandSegment_FilterBodyShouldTakeOneParameter(lambda.Parameters.Count), "filter");
            } 
        }
 
        #endregion Private methods. 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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ExpandSegment.cs source code in C# .NET

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