{"id":271,"date":"2015-01-11T18:50:51","date_gmt":"2015-01-11T17:50:51","guid":{"rendered":"http:\/\/www.cymbeline.ch\/?p=271"},"modified":"2015-01-19T22:25:26","modified_gmt":"2015-01-19T21:25:26","slug":"lucene-net-object-mapping","status":"publish","type":"post","link":"https:\/\/cymbeline.ch\/2015\/01\/11\/lucene-net-object-mapping\/","title":{"rendered":"Lucene.Net Object Mapping"},"content":{"rendered":"

Today I finally took some time to turn a little library I’ve used for a while now into a NuGet package, called Lucene.Net.ObjectMapping<\/a><\/strong>. At the same time, I also uploaded the code to GitHub<\/a><\/strong>. But let’s look at Lucene.Net Object Mapping in more detail.<\/p>\n

How To Install<\/h2>\n

Since this is a NuGet package, installation is as simple as running the following command in the Package Manager Console<\/p>\n

Install-Package Lucene.Net.ObjectMapping<\/pre>\n
Alternatively, you can just search for Lucene.Net.ObjectMapping<\/em> in the package manager and you should find it.<\/p>\n
How To Use It?<\/h2>\n
Using object mapping is as simple as calling two methods: ToDocument<\/em> to convert an object into a document and ToObject<\/em> to convert a Document (that was created with the ToDocument<\/em> method) into the original object.<\/p>\n
\r\nMyObject obj = ...;\r\nDocument doc = obj.ToDocument();\r\n\/\/ Save the document to your Lucene.Net Index\r\n\r\n\/\/ Later, load the document from the index again\r\nDocument docFromIndex = ...;\r\nMyObject objFromDoc = docFromIndex.ToObject<MyObject>();\r\n<\/pre>\n
How does it work?<\/h2>\n
Under the covers, the library is JSON-serializing the object and stores the JSON in the actual Lucene.Net document. In addition, it stores some metadata like the actual and the static types of the object you stored, as well as the timestamp (ticks) of when the document was created. The type information is used when you search for documents that were created for a specific type. The static type is the type you pass in as the type parameter to ToDocument<\/em>, whereas the actual type is the actual (dynamic) type of the object you’re passing in. Since all this information is stored in the document too, there are no issues re-creating objects from an class hierarchy too.
\nIn addition to storing the object information itself, the library also indexes the individual properties of the object you’re storing, including nested properties. By default, it uses a mapper which works as follows.<\/p>\n