pathexpressionparser.cs

NHibernate NET开发者所需的

using System;
using System.Collections;
using System.Text;
using NHibernate.Engine;
using NHibernate.Persister.Collection;
using NHibernate.Persister.Entity;
using NHibernate.SqlCommand;
using NHibernate.Type;
using NHibernate.Util;
using System.Collections.Generic;

namespace NHibernate.Hql.Classic
{
	/// <summary> 
	/// Parses an expression of the form foo.bar.baz and builds up an expression
	/// involving two less table joins than there are path components.
	/// </summary>
	public class PathExpressionParser : IParser
	{
		//TODO: this class does too many things! we need a different 
		//kind of path expression parser for each of the different 
		//ways in which path expressions can occur 

		//We should actually rework this class to not implement Parser 
		//and just process path expressions in the most convenient way.

		//The class is now way to complex!

		public const string EntityID = "id";

		public const string EntityClass = "class";

		private int dotcount;
		private string currentName;
		private string currentProperty;
		private string oneToOneOwnerName;
		private IAssociationType ownerAssociationType;
		private string[] columns;
		private string collectionName;
		private string collectionOwnerName;
		private string collectionRole;
		private readonly StringBuilder componentPath = new StringBuilder();
		//private string componentPath;
		private IType type;
		private readonly StringBuilder path = new StringBuilder();
		private bool ignoreInitialJoin;
		private bool continuation;
		private JoinType joinType = JoinType.InnerJoin; //default mode
		private bool useThetaStyleJoin = true;
		private IPropertyMapping currentPropertyMapping;
		private JoinSequence joinSequence;

		public JoinType JoinType
		{
			get { return joinType; }
			set { joinType = value; }
		}

		public bool UseThetaStyleJoin
		{
			get { return useThetaStyleJoin; }
			set { useThetaStyleJoin = value; }
		}

		private IPropertyMapping PropertyMapping
		{
			get { return currentPropertyMapping; }
		}

		private void AddJoin(string name, IAssociationType joinableType)
		{
			AddJoin(name, joinableType, CurrentColumns());
		}

		private void AddJoin(string name, IAssociationType joinableType, string[] foreignKeyColumns)
		{
			try
			{
				joinSequence.AddJoin(joinableType, name, joinType, foreignKeyColumns);
			}
			catch (MappingException me)
			{
				throw new QueryException(me);
			}
		}

		public string ContinueFromManyToMany(string clazz, string[] joinColumns, QueryTranslator q)
		{
			Start(q);
			continuation = true;
			currentName = q.CreateNameFor(clazz);
			q.AddType(currentName, clazz);
			IQueryable classPersister = q.GetPersister(clazz);
			AddJoin(currentName, TypeFactory.ManyToOne(clazz), joinColumns);
			currentPropertyMapping = classPersister;
			return currentName;
		}

		public void IgnoreInitialJoin()
		{
			ignoreInitialJoin = true;
		}

		public void Token(string token, QueryTranslator q)
		{
			if (token != null)
			{
				path.Append(token);
			}

			string alias = q.GetPathAlias(path.ToString());
			if (alias != null)
			{
				Reset(q); //reset the dotcount (but not the path)
				currentName = alias; //after reset!
				currentPropertyMapping = q.GetPropertyMapping(currentName);
				if (!ignoreInitialJoin)
				{
					JoinSequence ojf = q.GetPathJoin(path.ToString());
					try
					{
						joinSequence.AddCondition(ojf.ToJoinFragment(q.EnabledFilters, true).ToWhereFragmentString); //after reset!
					}
					catch (MappingException me)
					{
						throw new QueryException(me);
					}
					// we don't need to worry about any condition in the ON clause
					// here (toFromFragmentString), since anything in the ON condition 
					// is already applied to the whole query
				}
			}
			else if (".".Equals(token))
			{
				dotcount++;
			}
			else
			{
				if (dotcount == 0)
				{
					if (!continuation)
					{
						if (!q.IsName(token))
						{
							throw new QueryException("undefined alias or unknown mapping: " + token);
						}
						currentName = token;
						currentPropertyMapping = q.GetPropertyMapping(currentName);
					}
				}
				else if (dotcount == 1)
				{
					if (currentName != null)
					{
						currentProperty = token;
					}
					else if (collectionName != null)
					{
						//IQueryableCollection p = q.GetCollectionPersister( collectionRole );
						//DoCollectionProperty( token, p, collectionName );
						continuation = false;
					}
					else
					{
						throw new QueryException("unexpected");
					}
				}
				else
				{
					// dotcount>=2

					// Do the corresponding RHS
					IType propertyType = PropertyType;

					if (propertyType == null)
					{
						throw new QueryException("unresolved property: " + currentProperty);
					}

					if (propertyType.IsComponentType)
					{
						DereferenceComponent(token);
					}
					else if (propertyType.IsEntityType)
					{
						DereferenceEntity(token, (EntityType) propertyType, q);
					}
					else if (propertyType.IsCollectionType)
					{
						DereferenceCollection(token, ((CollectionType) propertyType).Role, q);
					}
					else if (token != null)
					{
						throw new QueryException("dereferenced: " + currentProperty);
					}
				}
			}
		}

		/// <summary>
		/// 
		/// </summary>
		/// <param name="propertyName"></param>
		/// <param name="propertyType"></param>
		/// <param name="q"></param>
		/// <remarks>NOTE: we avoid joining to the next table if the named property is just the foreign key value</remarks>
		private void DereferenceEntity(string propertyName, EntityType propertyType, QueryTranslator q)
		{
			//if its "id"
			bool isIdShortcut = EntityID.Equals(propertyName) && !propertyType.IsUniqueKeyReference;

			//or its the id property name
			string idPropertyName;
			try
			{
				idPropertyName = propertyType.GetIdentifierOrUniqueKeyPropertyName(q.Factory);
			}
			catch (MappingException me)
			{
				throw new QueryException(me);
			}
			bool isNamedIdPropertyShortcut = idPropertyName != null && idPropertyName.Equals(propertyName);

			if (isIdShortcut || isNamedIdPropertyShortcut)
			{
				// special shortcut for id properties, skip the join!
				// this must only occur at the _end_ of a path expression
				DereferenceProperty(propertyName);
			}
			else
			{
				string entityClass = propertyType.GetAssociatedEntityName();
				string name = q.CreateNameFor(entityClass);
				q.AddType(name, entityClass);
				//String[] keyColNames = memberPersister.getIdentifierColumnNames();
				AddJoin(name, propertyType);
                if (propertyType.IsOneToOne)
                {
                    oneToOneOwnerName = currentName;
                }
                else
                {
                    oneToOneOwnerName = null;
                }
				ownerAssociationType = propertyType;
				currentName = name;
				currentProperty = propertyName;
				q.AddPathAliasAndJoin(path.ToString(0, path.ToString().LastIndexOf(StringHelper.Dot)), name, joinSequence.Copy());
				componentPath.Length = 0;
				currentPropertyMapping = q.GetPersister(entityClass);
			}
		}

		private void DereferenceProperty(string propertyName)
		{
			if (propertyName != null)
			{
				if (componentPath.Length > 0)
					componentPath.Append(StringHelper.Dot);

				componentPath.Append(propertyName);
			}
		}

		private void DereferenceComponent(string propertyName)
		{
			DereferenceProperty(propertyName);
		}

		private void DereferenceCollection(String propertyName, String role, QueryTranslator q)
		{
			collectionRole = role;
			IQueryableCollection collPersister = q.GetCollectionPersister(role);
			string name = q.CreateNameForCollection(role);
			AddJoin(name, collPersister.CollectionType);

			//if ( collPersister.HasWhere ) 
			//{
			//    join.AddCondition( collPersister.GetSQLWhereString( name ) );
			//}

			collectionName = name;
			collectionOwnerName = currentName;
			currentName = name;
			currentProperty = propertyName;
			componentPath.Length = 0;
			//componentPath = new StringBuilder();
			currentPropertyMapping = new CollectionPropertyMapping(collPersister);
		}

		private string PropertyPath
		{
			get
			{
				if (currentProperty == null)
				{
					return EntityID;
				}
				else if (componentPath != null && componentPath.Length > 0)
				{
					return currentProperty + StringHelper.Dot + componentPath;
				}
				else
				{
					return currentProperty;
				}
			}
		}

		private void SetType(QueryTranslator q)
		{
			if (currentProperty == null)
			{
				type = PropertyMapping.Type;
			}
			else
			{
				type = PropertyType;
			}
		}

		/// <summary>
		/// 
		/// </summary>
		/// <returns></returns>
		protected IType PropertyType
		{
			get
			{
				IType t = PropertyMapping.ToType(PropertyPath);
				if (t == null)
				{
					throw new QueryException("could not resolve property type: " + PropertyPath);
				}

				return t;
			}
		}

		/// <summary>