Fix some static analysis issues

src/NHapi.Base/EventMapper.cs

@@ -10,7 +10,7 @@ internal class EventMapper
     {
         private static readonly EventMapper InstanceValue = new EventMapper();
 
-        private Hashtable map = new Hashtable();
+        private readonly Hashtable map = new Hashtable();
 
         static EventMapper()
         {

src/NHapi.Base/Log/HapiLogImpl.cs

@@ -20,7 +20,7 @@ namespace NHapi.Base.Log
     /// </version>
     public class HapiLogImpl : IHapiLog
     {
-        private ILog innerLog;
+        private readonly ILog innerLog;
 
         internal HapiLogImpl(ILog log)
         {

src/NHapi.Base/Model/AbstractGroup.cs

@@ -44,8 +44,8 @@ public abstract class AbstractGroup : IGroup
     {
         private static readonly IHapiLog Log;
 
+        private readonly IModelClassFactory myFactory;
         private List<AbstractGroupItem> items;
-        private IModelClassFactory myFactory;
 
         static AbstractGroup()
         {

src/NHapi.Base/Model/AbstractSegmentItem.cs

@@ -5,7 +5,7 @@ namespace NHapi.Base.Model
 
     internal class AbstractSegmentItem
     {
-        private List<object> args = new List<object>();
+        private readonly List<object> args = new List<object>();
         private int maxReps = -1;
 
         /// <summary>

src/NHapi.Base/Model/ExtraComponents.cs

@@ -31,8 +31,8 @@ namespace NHapi.Base.Model
     /// <author>Bryan Tripp.</author>
     public class ExtraComponents
     {
-        private ArrayList comps;
-        private IMessage message;
+        private readonly ArrayList comps;
+        private readonly IMessage message;
 
         /// <summary>
         /// Creates a new instance of ExtraComponents.

src/NHapi.Base/Model/GenericComposite.cs

@@ -11,7 +11,7 @@ namespace NHapi.Base.Model
     /// <author>Bryan Tripp.</author>
     public class GenericComposite : AbstractType, IComposite
     {
-        private ArrayList components;
+        private readonly ArrayList components;
 
         /// <summary>
         /// Creates a new instance of GenericComposite.

src/NHapi.Base/Model/GenericGroup.cs

@@ -11,7 +11,7 @@ namespace NHapi.Base.Model
     /// <author>Bryan Tripp.</author>
     public class GenericGroup : AbstractGroup
     {
-        private string name;
+        private readonly string name;
 
         /// <summary>Creates a new instance of GenericGroup. </summary>
         public GenericGroup(IGroup parent, string name, IModelClassFactory factory)

src/NHapi.Base/Parser/EncodingCharacters.cs

@@ -209,9 +209,9 @@ public virtual object Clone()
             return new EncodingCharacters(this);
         }
 
-        public override bool Equals(object o)
+        public override bool Equals(object obj)
         {
-            if (o is EncodingCharacters other)
+            if (obj is EncodingCharacters other)
             {
                 return FieldSeparator == other.FieldSeparator &&
                        ComponentSeparator == other.ComponentSeparator &&

src/NHapi.Base/Parser/MessageIterator.cs

@@ -422,14 +422,14 @@ public int Rep
             /// <summary>
             /// Override equals.
             /// </summary>
-            /// <param name="o"></param>
+            /// <param name="obj"></param>
             /// <returns></returns>
-            public override bool Equals(object o)
+            public override bool Equals(object obj)
             {
                 var equals = false;
-                if (o != null && o is Index)
+                if (obj != null && obj is Index)
                 {
-                    var i = (Index)o;
+                    var i = (Index)obj;
                     if (i.Rep == Rep && i.Name.Equals(Name))
                     {
                         equals = true;

src/NHapi.Base/Parser/XMLParser.cs

@@ -50,7 +50,7 @@ public abstract class XMLParser : ParserBase
     {
         private static readonly IHapiLog Log;
 
-        private XmlDocument parser;
+        private readonly XmlDocument parser;
 
         /// <summary>
         /// The nodes whose names match these strings will be kept as original,

src/NHapi.Base/Util/FilterIterator.cs

@@ -47,8 +47,8 @@ namespace NHapi.Base.Util
     /// </summary>
     public class FilterIterator : IEnumerator
     {
-        private IPredicate predicate;
-        private IEnumerator iter;
+        private readonly IPredicate predicate;
+        private readonly IEnumerator iter;
         private object nextObject;
         private bool nextObjectSet = false;
 

src/NHapi.Base/Util/MessageIterator.cs

@@ -26,10 +26,10 @@ public class MessageIterator : IEnumerator
     {
         private static readonly IHapiLog Log;
 
+        private readonly bool handleUnexpectedSegments;
         private IStructure currentStructure;
         private string direction;
         private Position nextRenamedField;
-        private bool handleUnexpectedSegments;
 
         static MessageIterator()
         {
@@ -662,14 +662,14 @@ public Index Index
             /// <summary>
             /// Override equals operator.
             /// </summary>
-            /// <param name="o">Object o.</param>
+            /// <param name="obj">Object obj.</param>
             /// <returns>true if objects are equal.</returns>
-            public override bool Equals(object o)
+            public override bool Equals(object obj)
             {
                 var equals = false;
-                if (o != null && o is Position)
+                if (obj != null && obj is Position)
                 {
-                    var p = (Position)o;
+                    var p = (Position)obj;
                     if (p.Parent.Equals(Parent) && p.Index.Equals(Index))
                     {
                         equals = true;

src/NHapi.Base/Util/MessageNavigator.cs

@@ -164,7 +164,7 @@ public virtual bool drillUp()
         public virtual bool DrillUp()
         {
             // pop the top group and resume search there
-            if (!(ancestors.Count == 0))
+            if (ancestors.Count != 0)
             {
                 var gc = (GroupContext)SupportClass.StackSupport.Pop(ancestors);
                 CurrentGroup = gc.Group;
@@ -375,12 +375,12 @@ private void DrillHere(IStructure destination)
             }
 
             Reset();
-            while (!(pathStack.Count == 0))
+            while (pathStack.Count != 0)
             {
                 var parent = (IGroup)SupportClass.StackSupport.Pop(pathStack);
                 var index = (MessageIterator.Index)SupportClass.StackSupport.Pop(indexStack);
                 var child = Search(parent.Names, index.Name);
-                if (!(pathStack.Count == 0))
+                if (pathStack.Count != 0)
                 {
                     DrillDown(child, 0);
                 }

src/NHapi.Base/Validation/MessageValidator.cs

@@ -42,8 +42,8 @@ public class MessageValidator
     {
         private static readonly IHapiLog OurLog;
 
-        private IValidationContext myContext;
-        private bool failOnError;
+        private readonly IValidationContext myContext;
+        private readonly bool failOnError;
 
         static MessageValidator()
         {