relpropertyhelper.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Query / InternalTrees / relpropertyhelper.cs / 1305376 / relpropertyhelper.cs
                        

                        
                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner  [....]
// @backupOwner [....] 
//--------------------------------------------------------------------- 

using System; 
using System.Collections.Generic;
using System.Globalization;
using System.Diagnostics;
using System.Data.Common; 
using System.Data.Metadata.Edm;
 
namespace System.Data.Query.InternalTrees 
{
 
    /// 
    /// A "Rel" property is best thought of as a collocated reference (aka foreign key).
    /// Any entity may have zero or more rel-properties carried along with it (purely
    /// as a means to optimize for common relationship traversal scenarios) 
    ///
    /// Although the definition is lax here, we only deal with RelProperties that 
    /// are one-ended (ie) the target multiplicity is at most One. 
    ///
    /// Consider for example, an Order entity with a (N:1) Order-Customer relationship. The Customer ref 
    /// will be treated as a rel property for the Order entity.
    /// Similarly, the OrderLine entity may have an Order ref rel property (assuming that there was
    /// a N:1 relationship between OrderLine and Order)
    ///  
    internal sealed class RelProperty
    { 
        #region private state 
        private readonly RelationshipType m_relationshipType;
        private readonly RelationshipEndMember m_fromEnd; 
        private readonly RelationshipEndMember m_toEnd;
        #endregion

        #region constructors 
        internal RelProperty(RelationshipType relationshipType, RelationshipEndMember fromEnd, RelationshipEndMember toEnd)
        { 
            m_relationshipType = relationshipType; 
            m_fromEnd = fromEnd;
            m_toEnd = toEnd; 
        }
        #endregion

        #region public APIs 
        /// 
        /// The relationship 
        ///  
        public RelationshipType Relationship { get { return m_relationshipType; } }
 
        /// 
        /// The source end of the relationship
        /// 
        public RelationshipEndMember FromEnd { get { return m_fromEnd; } } 

        ///  
        /// the target end of the relationship 
        /// 
        public RelationshipEndMember ToEnd { get { return m_toEnd; } } 

        /// 
        /// Our definition of equality
        ///  
        /// 
        ///  
        public override bool Equals(object obj) 
        {
            RelProperty other = obj as RelProperty; 
            return (other != null &&
                this.Relationship.EdmEquals(other.Relationship) &&
                this.FromEnd.EdmEquals(other.FromEnd) &&
                this.ToEnd.EdmEquals(other.ToEnd)); 
        }
 
        ///  
        /// our hash code
        ///  
        /// 
        public override int GetHashCode()
        {
            return this.ToEnd.Identity.GetHashCode(); 
        }
 
        ///  
        /// String form
        ///  
        /// 
        [DebuggerNonUserCode]
        public override string ToString()
        { 
            return m_relationshipType.ToString() + ":" +
                m_fromEnd.ToString() + ":" + 
                m_toEnd.ToString(); 
        }
 
        #endregion
    }

    ///  
    /// A helper class for all rel-properties
    ///  
    internal sealed class RelPropertyHelper 
    {
        #region private state 
        private Dictionary> _relPropertyMap;
        private HashSet _interestingRelProperties;
        #endregion
 
        #region private methods
        ///  
        /// Add the rel property induced by the specified relationship, (if the target 
        /// end has a multiplicity of one)
        /// We only keep track of rel-properties that are "interesting" 
        /// 
        /// the association relationship
        /// source end of the relationship traversal
        /// target end of the traversal 
        private void AddRelProperty(AssociationType associationType,
            AssociationEndMember fromEnd, AssociationEndMember toEnd) 
        { 
            if (toEnd.RelationshipMultiplicity == RelationshipMultiplicity.Many)
            { 
                return;
            }
            RelProperty prop = new RelProperty(associationType, fromEnd, toEnd);
            if (_interestingRelProperties == null || 
                !_interestingRelProperties.Contains(prop))
            { 
                return; 
            }
 
            EntityTypeBase entityType = (EntityTypeBase)((RefType)fromEnd.TypeUsage.EdmType).ElementType;
            List propList;
            if (!_relPropertyMap.TryGetValue(entityType, out propList))
            { 
                propList = new List();
                _relPropertyMap[entityType] = propList; 
            } 
            propList.Add(prop);
        } 

        /// 
        /// Add any rel properties that are induced by the supplied relationship
        ///  
        /// the relationship
        private void ProcessRelationship(RelationshipType relationshipType) 
        { 
            AssociationType associationType = relationshipType as AssociationType;
            if (associationType == null) 
            {
                return;
            }
 
            // Handle only binary associations
            if (associationType.AssociationEndMembers.Count != 2) 
            { 
                return;
            } 

            AssociationEndMember end0 = associationType.AssociationEndMembers[0];
            AssociationEndMember end1 = associationType.AssociationEndMembers[1];
 
            AddRelProperty(associationType, end0, end1);
            AddRelProperty(associationType, end1, end0); 
        } 

        #endregion 

        #region constructors
        internal RelPropertyHelper(MetadataWorkspace ws, HashSet interestingRelProperties)
        { 
            _relPropertyMap = new Dictionary>();
            _interestingRelProperties = interestingRelProperties; 
 
            foreach (RelationshipType relationshipType in ws.GetItems(DataSpace.CSpace))
            { 
                ProcessRelationship(relationshipType);
            }
        }
        #endregion 

        #region public APIs 
 
        /// 
        /// Get the rel properties declared by this type (and *not* by any of its subtypes) 
        /// 
        /// the entity type
        /// set of rel properties declared for this type
        internal IEnumerable GetDeclaredOnlyRelProperties(EntityTypeBase entityType) 
        {
            List relProperties; 
            if (_relPropertyMap.TryGetValue(entityType, out relProperties)) 
            {
                foreach (RelProperty p in relProperties) 
                {
                    yield return p;
                }
            } 
            yield break;
        } 
 
        /// 
        /// Get the rel-properties of this entity and its supertypes (starting from the root) 
        /// 
        /// the entity type
        /// set of rel-properties for this entity type (and its supertypes)
        internal IEnumerable GetRelProperties(EntityTypeBase entityType) 
        {
            if (entityType.BaseType != null) 
            { 
                foreach (RelProperty p in GetRelProperties(entityType.BaseType as EntityTypeBase))
                { 
                    yield return p;
                }
            }
 
            foreach (RelProperty p in GetDeclaredOnlyRelProperties(entityType))
            { 
                yield return p; 
            }
 
        }

        #endregion
    } 

} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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