The changes for ShouldSerializeXXX implementation

Bson/Serialization/BsonClassMap.cs

@@ -34,6 +34,7 @@ namespace MongoDB.Bson.Serialization {
     /// </summary>
     public abstract class BsonClassMap {
         #region private static fields
+        private static object staticLock = new object();
         private static List<FilteredConventionProfile> profiles = new List<FilteredConventionProfile>();
         private static ConventionProfile defaultProfile = ConventionProfile.GetDefault();
         private static Dictionary<Type, BsonClassMap> classMaps = new Dictionary<Type, BsonClassMap>();
@@ -235,7 +236,7 @@ namespace MongoDB.Bson.Serialization {
         public static BsonClassMap LookupClassMap(
             Type classType
         ) {
-            lock (BsonSerializer.ConfigLock) {
+            lock (staticLock) {
                 BsonClassMap classMap;
                 if (!classMaps.TryGetValue(classType, out classMap)) {
                     // automatically create a classMap for classType and register it
@@ -296,7 +297,7 @@ namespace MongoDB.Bson.Serialization {
         public static void RegisterClassMap(
             BsonClassMap classMap
         ) {
-            lock (BsonSerializer.ConfigLock) {
+            lock (staticLock) {
                 // note: class maps can NOT be replaced (because derived classes refer to existing instance)
                 classMaps.Add(classMap.ClassType, classMap);
                 BsonDefaultSerializer.RegisterDiscriminator(classMap.ClassType, classMap.Discriminator);
@@ -346,7 +347,7 @@ namespace MongoDB.Bson.Serialization {
         /// </summary>
         /// <returns>The class map.</returns>
         public BsonClassMap Freeze() {
-            lock (BsonSerializer.ConfigLock) {
+            lock (staticLock) {
                 if (!frozen) {
                     freezeNestingLevel++;
                     try {
@@ -806,7 +807,12 @@ namespace MongoDB.Bson.Serialization {
             var defaultValue = conventions.DefaultValueConvention.GetDefaultValue(memberInfo);
             if (defaultValue != null) {
                 memberMap.SetDefaultValue(defaultValue);
-            }
+            }
+
+            // see if there is a function called ShouldSerializeXXX in the type definition with the signature
+            // public bool ShouldSerializeXXX();
+            // if it exists then it will be checked before the member is serialized.
+			memberMap.SetShouldSerializeValueMethod(memberInfo);
 
             foreach (var attribute in memberInfo.GetCustomAttributes(false)) {
                 var defaultValueAttribute = attribute as BsonDefaultValueAttribute;

Bson/Serialization/BsonClassMapSerializer.cs

@@ -320,6 +320,10 @@ namespace MongoDB.Bson.Serialization {
             if (memberMap.HasDefaultValue && !memberMap.SerializeDefaultValue && object.Equals(value, memberMap.DefaultValue)) {
                 return; // don't serialize default value
             }
+            if (!memberMap.ShouldSerializeValue(obj))
+            {
+                return;// the object determined that it does not need serialization.
+            }
 
             bsonWriter.WriteName(memberMap.ElementName);
             var nominalType = memberMap.MemberType;

Bson/Serialization/BsonMemberMap.cs

@@ -45,7 +45,8 @@ namespace MongoDB.Bson.Serialization {
         private IIdGenerator idGenerator;
         private bool isRequired;
         private bool hasDefaultValue;
-        private bool serializeDefaultValue = true;
+        private bool serializeDefaultValue = true;
+        private Func<object, bool> shouldSerializeValueMethod = (instance) => true;
         private bool ignoreIfNull;
         private object defaultValue;
         #endregion
@@ -180,6 +181,11 @@ namespace MongoDB.Bson.Serialization {
         /// </summary>
         public bool SerializeDefaultValue {
             get { return serializeDefaultValue; }
+        }
+
+        public Func<object, bool> ShouldSerializeValue
+        {
+            get { return shouldSerializeValueMethod; }
         }
 
         /// <summary>
@@ -359,10 +365,45 @@ namespace MongoDB.Bson.Serialization {
         ) {
             this.serializeDefaultValue = serializeDefaultValue;
             return this;
+        }
+
+        /// <summary>
+        /// Sets the ShouldSerializeValue handler which will determine if the value should be 
+        /// serialized
+        /// </summary>
+        /// <param name="methodInfo">The MemberInfo that needs to be checked for ShouldSerializeXXX method </param>
+        /// <returns>The member map.</returns>
+        public BsonMemberMap SetShouldSerializeValueMethod(MemberInfo memberInfo)
+        {
+            // see if there is a function called ShouldSerializeXXX in the type definition with the signature
+            // public bool ShouldSerializeXXX();
+            // if it exists then it will be checked before the member is serialized.
+            MethodInfo shouldSerializeMethod = null;
+            var memberName = memberInfo.Name;
+			var declaringType = memberInfo.DeclaringType;
+						
+			// Search for a method which has the name ShouldSerializeXXX and takes no arguments
+            shouldSerializeMethod = declaringType.GetMethod("ShouldSerialize" + memberName, new Type[] { });
+            if (shouldSerializeMethod != null && 
+				shouldSerializeMethod.IsPublic && 
+				shouldSerializeMethod.ReturnType == typeof(bool))
+            {
+	            var instance = Expression.Parameter(typeof(object), "obj");
+	            var mce = Expression.Call(
+	                Expression.Convert(instance, declaringType),
+	                shouldSerializeMethod);
+	            var lambda = Expression.Lambda<Func<object, bool>>(mce, instance);
+	
+	            shouldSerializeValueMethod = lambda.Compile();
+            }
+
+            return this;
         }
+		
         #endregion
 
-        #region private methods
+        #region private methods
+
         private Action<object, object> GetFieldSetter() {
             var fieldInfo = (FieldInfo) memberInfo;
 

BsonUnitTests/DefaultSerializer/BsonClassMapTests.cs

@@ -215,4 +215,40 @@ namespace MongoDB.BsonUnitTests.Serialization {
             Assert.AreEqual("X", memberMap.MemberName);
         }
     }
+	
+	[TestFixture]
+	public class BsonShouldSerializeTests {
+		
+	    public class ClassA
+	    {
+	        public string LocalName { get; set; }
+		
+	        public DateTime AsOfUtc { get; set; }
+	
+	        public bool ShouldSerializeAsOfUtc()
+	        {
+	            return this.AsOfUtc != DateTime.MinValue;
+	        }
+	    }
+		
+		[Test]
+		public void TestShouldSerializeSuccess() {
+			var c = new ClassA();
+			c.AsOfUtc = DateTime.MinValue;
+			c.LocalName = "Saleem";
+			var json = c.ToJson();
+			var expected = "{ 'LocalName' : 'Saleem' }".Replace("'", "\"");
+
+			Assert.AreEqual(expected, json);
+						
+			// Test to see if the value is serialized
+			var date =  new DateTime(2011, 4, 24, 0, 0, 0);
+			date = DateTime.SpecifyKind(date, DateTimeKind.Utc);
+			c.AsOfUtc = date;			
+			expected = "{ 'LocalName' : 'Saleem', 'AsOfUtc' : ISODate('2011-04-24T00:00:00Z') }".Replace("'", "\"");
+			json = c.ToJson();
+			Assert.AreEqual(expected, json);			
+		}
+		
+	}
 }