DefaultSaxWriter now writes to any Appendable, rather than a PrintWri…

…ter.

If the Appendable is a StringBuilder, this should be more efficient.

Rather than StringEscaper having mutable/immutable modes, split out a Builder.
StringEscaper can now write to any Appendable (including StringBuilder and Writer).
StringEscaper replaces some ad hoc escaping methods in XmlaUtils.

Clean up Composite; EmptyIterator is a bit more efficient.

Fix some checkFile exceptions.

NOTICE

@@ -0,0 +1,12 @@
+olap4j-xmlaserver
+
+===============================================================================
+This product includes software from the Mondrian project.
+
+Copyright (C) 2001-2005 Julian Hyde
+Copyright (C) 2005-2012 Pentaho and others
+
+===============================================================================
+The StringEscaper class comes from the eigenbase-xom project.
+
+Copyright (C) 2005 Dynamo BI Corporation

src/main/java/mondrian/xmla/XmlaConstants.java

@@ -50,12 +50,12 @@ public interface XmlaConstants {
 
     public static final String SOAP_PREFIX = "SOAP-ENV";
 
-    /*
+    /**
      * Soap Header mustUnderstand attribute name.
      */
     public static final String SOAP_MUST_UNDERSTAND_ATTR = "mustUnderstand";
 
-    /*
+    /**
      * Soap XMLA Header elements and attribute names.
      */
     public static final String XMLA_BEGIN_SESSION      = "BeginSession";
@@ -64,9 +64,8 @@ public interface XmlaConstants {
     public static final String XMLA_SESSION_ID         = "SessionId";
     public static final String XMLA_SECURITY           = "Security";
 
-    /*
-     * Names of context keys known by both callbacks and Mondrian code.
-     */
+    // Names of context keys known by both callbacks and Mondrian code.
+
     // context key for role name storage
     public static final String CONTEXT_ROLE_NAME   = "role_name";
     // context key for language (SOAP or JSON)

src/main/java/mondrian/xmla/XmlaRequestCallback.java

@@ -40,12 +40,11 @@ public static XmlaException authorizationException(Exception ex) {
                 ex);
         }
 
-        /*
-    HTTP/1.1 100 Continue
-    Server: Microsoft-IIS/5.0
-    Date: Tue, 21 Feb 2006 21:07:57 GMT
-    X-Powered-By: ASP.NET
-        */
+
+        // HTTP/1.1 100 Continue
+        // Server: Microsoft-IIS/5.0
+        // Date: Tue, 21 Feb 2006 21:07:57 GMT
+        // X-Powered-By: ASP.NET
         public static void generatedExpectResponse(
             HttpServletRequest request,
             HttpServletResponse response,

src/main/java/mondrian/xmla/impl/AuthenticatingXmlaRequestCallback.java

@@ -58,11 +58,9 @@ public void preAction(
         Map<String, Object> context)
         throws Exception
     {
-        /*
-         * This is where the magic happens. At this stage, we have
-         * the username/password known. We will delegate the authentication
-         * process down to the subclass.
-         */
+        // This is where the magic happens. At this stage, we have
+        // the username/password known. We will delegate the authentication
+        // process down to the subclass.
         final String roleNames =
             authenticate(
                 (String) context.get(XmlaConstants.CONTEXT_XMLA_USERNAME),