NH-2888 - Add support to ICriteria to eager fetch lazy properties

Allows fetching of root entity, one-to-one and many-to-one associations

Author: stuartcarnie

src/NHibernate.Test/Criteria/FetchAllProperties/Article.cs

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+using System.Collections.Generic;
+
+namespace NHibernate.Test.Criteria.FetchAllProperties
+{
+    public class Article
+    {
+        public Article()
+        {
+            Comments = new HashSet<Comment>();
+        }
+
+        public virtual long Id { get; set; }
+
+        public virtual string Title { get; set; }
+
+        public virtual string Description { get; set; }
+
+        public virtual ISet<Comment> Comments { get; set; }
+
+        public virtual ArticleExtension ArticleExtension { get; set; }
+    }
+
+    public class ArticleExtension
+    {
+        public virtual long Id { get; set; }
+
+        public virtual Article Article { get; set; }
+
+        public virtual int Rating { get; set; }
+
+        public virtual string Notes { get; set; }
+    }
+
+    public class Comment
+    {
+        public virtual long Id { get; set; }
+
+        public virtual string Subject { get; set; }
+
+        public virtual string Text { get; set; }
+
+        public virtual Article Article { get; set; }
+    }
+}

src/NHibernate.Test/Criteria/FetchAllProperties/Article.hbm.xml

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+<?xml version="1.0" encoding="utf-8" ?>
+<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
+	assembly="NHibernate.Test"
+	namespace="NHibernate.Test.Criteria.FetchAllProperties"
+	default-access="property"
+	default-lazy="true">
+
+  <class name="Article" table="Article">
+    <id name="Id" type="Int64">
+      <generator class="native"/>
+    </id>
+    <property name="Title" />
+    <property name="Description" lazy="true"/>
+    <set name="Comments" inverse="true" cascade="all-delete-orphan">
+      <key column="article_id"/>
+      <one-to-many class="Comment"/>
+    </set>
+
+    <one-to-one name="ArticleExtension" class="ArticleExtension" cascade="all" lazy="false" />
+  </class>
+
+  <class name="ArticleExtension" table="ArticleExtension">
+    <id name="Id" type="Int64">
+      <generator class="foreign">
+        <param name="property">Article</param>
+      </generator>
+    </id>
+
+    <property name="Rating" />
+    <property name="Notes" lazy="true" />
+
+    <one-to-one name="Article" class="Article" constrained="true" />
+  </class>
+
+  <class name="Comment" table="Comment">
+    <id name="Id" type="Int64">
+      <generator class="native" />
+    </id>
+    <property name="Subject" />
+    <property name="Text" lazy="true"/>
+    <many-to-one name="Article" column="article_id"/>
+  </class>
+
+</hibernate-mapping>

src/NHibernate.Test/Criteria/FetchAllProperties/BlogPost.cs

@@ -0,0 +1,11 @@
+namespace NHibernate.Test.Criteria.FetchAllProperties
+{
+    public class BlogPost
+    {
+        public virtual long Id { get; set; }
+
+        public virtual string Title { get; set; }
+
+        public virtual string Description { get; set; }
+    }
+}

src/NHibernate.Test/Criteria/FetchAllProperties/BlogPost.hbm.xml

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+<?xml version="1.0" encoding="utf-8" ?>
+<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
+	assembly="NHibernate.Test"
+	namespace="NHibernate.Test.Criteria.FetchAllProperties"
+	default-access="property"
+	default-lazy="true">
+
+  <class name="BlogPost" table="BlogPost">
+    <id name="Id" type="Int64">
+      <generator class="native"/>
+    </id>
+    <property name="Title" />
+    <property name="Description" lazy="true"/>
+  </class>
+
+</hibernate-mapping>

src/NHibernate.Test/Criteria/FetchAllProperties/FetchAllPropertiesTests.cs

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+using System;
+using System.Collections;
+using NUnit.Framework;
+
+namespace NHibernate.Test.Criteria.FetchAllProperties
+{
+    [TestFixture]
+    public class FetchAllPropertiesTests : TestCase
+    {
+        #region Overrides of TestCase
+
+        protected override string MappingsAssembly
+        {
+            get { return "NHibernate.Test"; }
+        }
+
+        protected override IList Mappings
+        {
+            get
+            {
+                return new[]
+                             {
+                                 "Criteria.FetchAllProperties.BlogPost.hbm.xml"
+                             };
+            }
+        }
+
+        protected override void OnSetUp()
+        {
+            using (ISession session = OpenSession())
+            {
+                ITransaction t = session.BeginTransaction();
+
+                BlogPost blogPost = new BlogPost();
+                blogPost.Title = "ICriteria supports eager property fetch!";
+                blogPost.Description = "It really does!";
+                session.Save(blogPost);
+
+                t.Commit();
+            }
+        }
+
+        protected override void OnTearDown()
+        {
+            using (ISession session = sessions.OpenSession())
+            {
+                session.Delete("from System.Object");
+                session.Flush();
+            }
+        }
+
+        #endregion
+
+        [Test]
+        public void DidLoadDescription()
+        {
+            BlogPost result;
+            using (ISession session = sessions.OpenSession())
+            {
+                result = session.CreateCriteria(typeof(BlogPost))
+                    .SetLazyPropertyFetchMode(LazyPropertyFetchMode.Select)
+                    .UniqueResult<BlogPost>();
+                
+                
+            }
+
+            Assert.DoesNotThrow(
+                delegate
+                    {
+                        Assert.That(String.IsNullOrEmpty(result.Description), Is.False, "Should have been a value in Description");
+                    }, "Should not have thrown an exception accessing the Description property");
+        }
+
+        [Test]
+        public void ShouldThrowExceptionWhenAccessingLazyPropertyOutsideSession()
+        {
+            BlogPost result;
+            using (ISession session = sessions.OpenSession())
+            {
+                result = session.CreateCriteria(typeof(BlogPost))
+                    .UniqueResult<BlogPost>();
+                
+                
+            }
+
+            Assert.Throws<LazyInitializationException>(
+                delegate
+                    {
+                        Assume.That(String.IsNullOrEmpty(result.Description), Is.True);
+                    }, "Should have thrown an exception accessing the Description property");
+        }
+    }
+}

src/NHibernate.Test/Criteria/FetchAllProperties/FetchAllPropertiesTestsWithRelationships.cs

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+using System;
+using System.Collections;
+using System.Linq;
+using NUnit.Framework;
+
+namespace NHibernate.Test.Criteria.FetchAllProperties
+{
+    [TestFixture]
+    public class FetchAllPropertiesTestsWithRelationships : TestCase
+    {
+        #region Overrides of TestCase
+
+        protected override string MappingsAssembly
+        {
+            get { return "NHibernate.Test"; }
+        }
+
+        protected override IList Mappings
+        {
+            get
+            {
+                return new[]
+                             {
+                                 "Criteria.FetchAllProperties.Article.hbm.xml"
+                             };
+            }
+        }
+
+        protected override void OnSetUp()
+        {
+            using (ISession session = OpenSession())
+            {
+                ITransaction t = session.BeginTransaction();
+
+                var article = new Article
+                                  {
+                                      Title = "Article one",
+                                      Description = "The descripition for article one",
+                                  };
+                article.Comments.Add(new Comment { Article = article, Subject = "Cool stuff", Text = "Cool stuff comment" });
+                article.Comments.Add(new Comment { Article = article, Subject = "Could it be true?", Text = "Fetch all in ICriteria rules" });
+                article.ArticleExtension = new ArticleExtension { Article = article, Rating = 3, Notes = "A few notes" };
+                session.Save(article);
+
+                var article2 = new Article
+                                   {
+                                       Title = "Article two",
+                                       Description = "The descripition for article two",
+                                   };
+                article2.Comments.Add(new Comment { Article = article, Subject = "The beatles", Text = "Are a great band" });
+                article2.Comments.Add(new Comment { Article = article, Subject = "See you thursday", Text = "Can't wait to grab beers at the new bar!" });
+                article2.ArticleExtension = new ArticleExtension { Article = article2, Rating = 5, Notes = "I don't like notes" }; 
+                session.Save(article2);
+
+                t.Commit();
+            }
+        }
+
+        protected override void OnTearDown()
+        {
+            using (ISession session = sessions.OpenSession())
+            {
+                session.Delete("from System.Object");
+                session.Flush();
+            }
+        }
+
+        #endregion
+
+        [Test]
+        public void CanEagerFetchRelatedPropertiesUsingSubcriteria()
+        {
+            Article result;
+            using (ISession session = sessions.OpenSession())
+            {
+                result = session.CreateCriteria(typeof(Article))
+                    .SetLazyPropertyFetchMode(LazyPropertyFetchMode.Select)
+                    .SetMaxResults(1)
+                    .CreateCriteria("ArticleExtension")
+                        .SetLazyPropertyFetchMode(LazyPropertyFetchMode.Select)
+                    .UniqueResult<Article>();
+            }
+
+            Assert.DoesNotThrow(
+                delegate
+                {
+                    Assert.That(String.IsNullOrEmpty(result.Description), Is.False, "Should have been a value in Description");
+                }, "Should not have thrown an exception accessing the Description property");
+
+            Assert.DoesNotThrow(
+                delegate
+                {
+                    Assert.That(String.IsNullOrEmpty(result.ArticleExtension.Notes), Is.False, "Should have been a value in ArticleExtension.Notes");
+                }, "Should not have thrown an exception accessing the ArticleExtension.Notes property");
+        }
+
+        [Test]
+        public void CanEagerFetchRelatedPropertiesUsingAssociationPath()
+        {
+            Article result;
+            using (ISession session = sessions.OpenSession())
+            {
+                result = session.CreateCriteria(typeof(Article))
+                    .SetLazyPropertyFetchMode(LazyPropertyFetchMode.Select)
+                    .SetLazyPropertyFetchMode("ArticleExtension", LazyPropertyFetchMode.Select)
+                    .SetMaxResults(1)
+                    .UniqueResult<Article>();
+            }
+
+            Assert.DoesNotThrow(
+                delegate
+                {
+                    Assert.That(String.IsNullOrEmpty(result.Description), Is.False, "Should have been a value in Description");
+                }, "Should not have thrown an exception accessing the Description property");
+
+            Assert.DoesNotThrow(
+                delegate
+                {
+                    Assert.That(String.IsNullOrEmpty(result.ArticleExtension.Notes), Is.False, "Should have been a value in ArticleExtension.Notes");
+                }, "Should not have thrown an exception accessing the ArticleExtension.Notes property");
+        }
+
+        [Test]
+        public void CanEagerFetchChildAndNotParentProperties()
+        {
+            Article result;
+            using (ISession session = sessions.OpenSession())
+            {
+                result = session.CreateCriteria(typeof(Article))
+                    .SetMaxResults(1)
+                    .CreateCriteria("ArticleExtension")
+                        .SetLazyPropertyFetchMode(LazyPropertyFetchMode.Select)
+                    .UniqueResult<Article>();
+            }
+
+            Assert.Throws<LazyInitializationException>(
+                delegate
+                {
+                    Assert.That(String.IsNullOrEmpty(result.Description), Is.True);
+                }, "Should have thrown an exception accessing the Description property");
+
+            Assert.DoesNotThrow(
+                delegate
+                {
+                    Assert.That(String.IsNullOrEmpty(result.ArticleExtension.Notes), Is.False, "Should have been a value in ArticleExtension.Notes");
+                }, "Should not have thrown an exception accessing the ArticleExtension.Notes property");
+        }
+
+        [Test]
+        public void CanEagerFetchParentAndNotChildProperties()
+        {
+            Article result;
+            using (ISession session = sessions.OpenSession())
+            {
+                result = session.CreateCriteria(typeof(Article))
+                    .SetMaxResults(1)
+                    .SetLazyPropertyFetchMode(LazyPropertyFetchMode.Select)
+                    .CreateCriteria("ArticleExtension")
+                    .UniqueResult<Article>();
+            }
+
+            Assert.DoesNotThrow(
+                delegate
+                {
+                    Assert.That(String.IsNullOrEmpty(result.Description), Is.False);
+                }, "Should not have thrown an exception accessing the Description property");
+
+            Assert.Throws<LazyInitializationException>(
+                delegate
+                {
+                    Assert.That(String.IsNullOrEmpty(result.ArticleExtension.Notes), Is.True);
+                }, "Should have thrown an exception accessing the ArticleExtension.Notes property");
+        }
+    }
+}