Extending the Flat File Disassembler Pipeline Component

The following sample illustrates how to create a custom disassembler to parse flat file documents that are UTF-7 encoded. To process UTF-7 documents, the component inherits from the FFDasmComp class and then overrides its GetDataReader method.

using System;  
using System.Text;  
using System.IO;  
using Microsoft.BizTalk.Message.Interop;  
using Microsoft.BizTalk.Component.Interop;  
using Microsoft.BizTalk.ParsingEngine;  
using Microsoft.BizTalk.Component;  
using System.Runtime.InteropServices;  
  
namespace Microsoft.BizTalk.Test  
{  
   /// <summary>  
   /// Implements FF disassembler which always uses UTF-7 encoding.  
   /// </summary>  
   [ComponentCategory(CategoryTypes.CATID_PipelineComponent)]  
   [ComponentCategory(CategoryTypes.CATID_DisassemblingParser)]  
   [ComponentCategory(CategoryTypes.CATID_Streamer)]  
   [Guid("A6E5F54F-7902-4e1a-84D8-5C7584F0ECF2")]  
   public class Utf7FFDasm :   
      FFDasmComp,  
      IBaseComponent  
   {  
      /// <summary>  
      /// Initializes a Utf7FFAsmDasm instance.  
      /// </summary>  
      public Utf7FFDasm()  
      {  
      }  
  
      /// <summary>  
      /// Name property  
      /// </summary>  
      public new string Name   
      {  
         get   
         {  
            return "UTF-7 FlatFile Disassembler";  
         }  
      }  
  
      /// <summary>  
      /// Version property  
      /// </summary>  
      public new string Version   
      {  
         get   
         {  
            return "1.0";  
         }  
      }  
  
      /// <summary>  
      /// Description property  
      /// </summary>  
      public new string Description   
      {  
         get   
         {  
            return "UTF-7 FlatFile Disassembler";  
         }  
      }  
  
      /// <summary>  
      /// Gets a data reader instance  
      /// </summary>  
      /// <param name="dataStream">Data stream</param>  
      /// <param name="dataEncoding">Data encoding</param>  
      /// <param name="detectEncodingFromByteOrderMarks">Detect encoding from a byte order mark</param>  
      /// <returns>IDataReader instance</returns>  
      protected override IDataReader GetDataReader(Stream dataStream, Encoding dataEncoding, bool detectEncodingFromByteOrderMarks)  
      {  
         // Delegate call to the base implementation passing fixed UTF-7 encoding  
            return base.GetDataReader(dataStream, Encoding.UTF7, false);  
      }  
   }  
}  

Example

The following example illustrates how to create a custom disassembler for transactional processing of flat file interchanges. It differs from the standard Flat File Disassembler in that it does not produce any disassembled documents until the entire input interchange is completely processed. This component implementation inherits from the FFDasmComp class and overrides the GetNext method. On the first call to the GetNext method, it processes all messages in the interchange, stores them in an ArrayList, and returns the first message from the ArrayList. On subsequent calls, it returns the next message from the ArrayList.

using System;  
using System.Collections;  
using System.Runtime.InteropServices;  
using Microsoft.BizTalk.Message.Interop;  
using Microsoft.BizTalk.Component.Interop;  
using Microsoft.BizTalk.Component;  
  
namespace Microsoft.BizTalk.Component  
{  
   /// <summary>  
   /// Summary description for Class1.  
   /// </summary>  
   [ComponentCategory(CategoryTypes.CATID_PipelineComponent)]  
   [ComponentCategory(CategoryTypes.CATID_DisassemblingParser)]  
   [Guid("EB4714A8-FD97-43de-84E2-E011648F349B")]  
   public class TransactionalFFDasm :   
      FFDasmComp,  
      IBaseComponent,  
      IDisassemblerComponent  
   {  
      public TransactionalFFDasm()  
      {  
      }  
  
      #region IBaseComponent Members  
  
      public new string Description  
      {  
         get  
         {  
            return "Transactional Flat File Disassembler";  
         }  
      }  
  
      public new string Name  
      {  
         get  
         {  
            return "Transactional Flat File Disassembler";  
         }  
      }  
  
      public new string Version  
      {  
         get  
         {  
            return "1.0";  
         }  
      }  
  
      #endregion  
  
      #region IDisassemblerComponent Members  
  
      public new void Disassemble(IPipelineContext pContext, IBaseMessage pInMsg)  
      {  
         base.Disassemble(pContext, pInMsg);  
      }  
  
      public new IBaseMessage GetNext(IPipelineContext pContext)  
      {  
         // Check if don't need to stop collecting messages  
         if (currentMessage == 0)  
         {  
            messageInterchange = new ArrayList();  
            currentMessage = 0;  
  
            // Collect messages from the standard disassembler  
            IBaseMessage disassembledMessage = null;  
            while ((disassembledMessage = base.GetNext(pContext)) != null)  
            {  
               byte[] buffer = new byte[4096];  
               int count = 0;  
  
               // Create a new memory stream to contain the disassembled message.  
               MemoryStream messageStream = new MemoryStream();  
  
               // Get a stream pointer to the disassembled stream.  
               Stream disassembledStream = disassembledMessage.BodyPart.GetOriginalDataStream();  
  
               // Write the disassembled message to the memory stream  
               while (0 != (count == disassembledStream.Read(buffer, 0, 4096)))  
               {  
                  messageStream.Write(buffer, 0, count);  
               } // end-while  
  
               // Rewind the stream to the beginning  
               messageStream.Seek(0, SeekOrigin.Begin);  
  
               // Replace the stream on the disassembled message with the memory stream.  
               disassembledMessage.BodyPart.data = messageStream;  
  
               // Add this message to the ArrayList of messages.  
               messageInterchange.Add(disassembledMessage);  
            } // end-while  
  
            // Check if no messages were collected, just return nothing  
            if (0 == messageInterchange.Count)  
               return null;  
         } // end-if  
  
         // Check if all collected messages are returned  
         if (currentMessage == messageInterchange.Count)  
            return null;  
  
         // Return the current collected message  
         return (IBaseMessage)messageInterchange[currentMessage++];  
      } // end-method GetNext()  
  
      #endregion  
  
      private ArrayList messageInterchange = null;  
      private int currentMessage = 0;  
   }  
}  
  

See Also

Developing a Disassembling Pipeline Component