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An Nhax NHAX file is a file format that is used to export/import data from Noah.

The Nhax format is a A NHAX file is mix of binary data and XML formatted data the so called sections. As the Nhax NHAX format is complex and hard to implement HIMSA has developed a standalone library that can be used by business system developers that must support the Nhax NHAX format.

Extension to Old Nhax NHAX Format

In order to increase the quality of the data the The data in Nhax NHAX sections is defined using XSD files. All data must validate with respect to the XSD when reading/writing Nhax NHAX files.

Furthermore the The Misc section is now used and is defined in and XSD file.

Link to binary Nhax NHAX format: Noah 4 Extended Native Format (Nhax and Enhax)

Link to XML Sections in Nhax NHAX Files: XML Sections in Nhax NHAX Files

Error Handling

In general Nhaxlib NhaxLib functions returns a ValidateResult class:

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Furthermore functions may throw exceptions.

Nhax NHAX Writer

The Nhax NHAX writer writes Noah data to an Nhax a NHAX file or a stream. The behavior of the NhaxWrites is define of the constructor called to make an instance of the writer. It may When writing data to a file the NHAXWriter will either produce a number of files of a given max size , or one file that contains all data or all data written to a stream.

/// <summary>
/// Write all data to one Nhax NHAX file.
/// </summary>
/// <param name="fullPath">Full path to Nhax NHAX file</param>
/// <param name="password">Password to access the file</param>
/// <param name="nhaxFileCreatedCallback">Function called when Nhax NHAX file is written. The function is called with the name of the file that is written. Can be set to null.</param>
/// <param name="overwriteExistingFiles">True existing files will be overwritten. If false an error will be reported if file exists.</param>
/// <param name="compressData">If true data are compressed</param>
public NhaxWriter(string fullPath, string password, NhaxFileCreatedCallback nhaxFileCreatedCallback = null, bool overwriteExistingFiles = false, bool compressData = true)

/// <summary>
/// NhaxWriter constructor that writes data to one or more Nhax NHAX files.
/// If more than one Nhax NHAX file are created the file will contain a Misc section containing al Misc data provided. The user section will only contain users that are referenced by patients or actions.
/// </summary>
/// <param name="path">Path where the files is stored</param>
/// <param name="filePrefix">The prefix of the Nhax NHAX file. The file name is "filePrefix-dddddd" where d is digit e.g. "file-000001", "file-000002"</param>
/// <param name="password">Password to access the file</param>
/// <param name="nhaxFileCreatedCallback">Function called when Nhax NHAX file is written. The function is called with the name of the file that is written. Can be set to null.</param>
/// <param name="overwriteExistingFiles">True existing files will be overwritten. If false an error will be reported if file exists.</param>
/// <param name="compressData">If true data are compressed</param>
/// <param name="maxFileSize">Max size of created file. When this size is reached a new Nhax new NHAX file is created and data written to this file.</param>
/// <param name="maxPatients">Max patients written to file. When this size is reached new NHAX file is created and data written to this file.</param>
public NhaxWriter(string path, string filePrefix, string password, NhaxFileCreatedCallback nhaxFileCreatedCallback = null, bool overwriteExistingFiles = false, bool compressData = true, long maxFileSize = ConstMaxFileSize, int maxPatients=ConstMaxPatients)

When the NhaxWriter instance has been created WriteUsers and WriteMiscData must be called in order to add users and add Misc data to the Nhax NHAX file. These functions must be called before the WritePatient is called. Each call of WritePatient will add a patient to the Nhax NHAX file.

If using the constructor that takes maxFileSize argument a new Nhax NHAX file is created when the file size exceeds the maxFileSize after a patient is written. When changing to new Nhax start writing a new NHAX file the nhaxFileCreatedCallback is called whith with name of created Nhax NHAX file. The default size of maxFileSize is the advised size when generating Nhax NHAX file that is used when migrating to NoahES.

It is possible to call the writeUsers WriteUsers multiple times but when . When writing patient data . The users - WritePatient - the user referred from a patient object data must be knowm when WritePatient is calledknown.

IMPORTANT: Be aware that the Nhax Writer NhaxWriter implements the idisposable interface. It is important that dispose is called in order to update the binary part of the Nhax NHAX file correctly.

Nhax NHAX Reader

The Nhax NHAX reader reads data from an Nhax NHAX file or a stream that contains an Nhax NHAX file. The Nhax NHAX reader can be initialized with file or a stream.

/// <summary>
/// Initializing Nhax NHAX file reader
/// </summary>
/// <param name="password">Password if Nhax NHAX file is encrypted</param>
public ValidateResult Initialize(string filePath, string password)

/// <summary>
/// Initializing Nhax NHAX stream reader
/// </summary>
/// <param name="inStream">Stream that contains Nhax NHAX formatted data</param>
/// <param name="password">Password if Nhax NHAX data is encrypted</param>
/// <returns></returns>
public ValidateResult Initialize(Stream inStream, string password)

Be aware that the Nhax NHAX reader implements the idisposable interface. It is important to called the dispose function.

When reading large Nhax NHAX files it is recommended to read a moderate number of patients.

Nhax NHAX Logger Interface

Logging in NhaxLib can be enable enabled either by implementing the Nhax NHAX logger interface INhaxLogger or create and use the simple logger that NhaxLib implements. The logger must be added using NhaxLogger.AddLogger.

...

string logPath = @"c:\..."
INhaxLogger Logger = NhaxLogger.CreateLogger(logPath, true, 10 * 1024 * 1024);
NhaxLogger.AddLogger(Logger, NhaxLogLevel.Debug);

Sample

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An example of a utility making use of the NhaxLib is available here: NHAX FileSplit (Preparing files for Migrator)

The sample code for it is provided under common SDK components at himsa.com