Netbeans has a pluggable architecture called DataLoader that allows you to implement your own loading mechanism of data files. Datasets instantiated through the DataLoader architecture will be cached automatically by NetBeans.

Registering a Data Loader

A registered Data Loader associates a file type with your own class implementing org.openide.loaders.MultiDataObject. Part of the contract of a MultiDataObject is that its lookup provides an instance of a class implementing IData. For instance:

MultiDataObject obj = ...

obj.getLookup(IData.class) will return an IData instance.

There are three things that you have to do to plug in your own DataLoader.

1. Register your DataLoader in the layer.xml

LAYER.XML

<folder name="Loaders">

        <folder name="seismic">

            <folder name="x-demo2d">

                <folder name="Factories">

                    <file name="Demo2DSeismicDataLoader.instance">

                        <attr name="dataObjectClass" stringvalue="com.interactive.intviewer.demoseismicdata.twod.DemoTwoDSeismicDataObject"/>

                        <attr name="instanceCreate" methodvalue="org.openide.loaders.DataLoaderPool.factory"/>

                    </file>

                </folder>

            </folder>

        </folder>

    </folder>

In this example, the file name "Demo2DSeismicDataLoader" is a unique name. The "dataObjectClass" attribute needs to be the fully qualified name of your MultiDataObject class. The "instanceCreate" attribute must be org.openide.loaders.DataLoaderPool.factory.

The "x-demo2d" folder in this example indicates the MIME type that this DataLoader should handle.

2. Implement a data object class, which extends org.openide.loaders.MultiDataObject. In addition to the constructor, there is only one method that must be implemented, which is the getLookup method.

3. Implement a data class, which implements com.interactive.intviewerapi.data.IData

Registering a MIME type

You will also need to implement your own MIME type. This is a very simple process, as all it takes is another layer.xml entry.

LAYER.XML

<folder name="MimeTypes">

    <folder name="seismic">

        <folder name="x-demo2d">

            <attr name="name" stringvalue="Demo2D"/>

            <attr name="ext" stringvalue="demo2d DEMO2D"/>

        </folder>

    </folder>

</folder>

The "name" attribute is just the name for your MIME type. It will be displayed in file choosers. The "ext" attribute is a list of all of the valid extensions for your MIME type. More information on how to handle mime types is available.

Examples

Follow this link for a sample implementation of seismic data loader that reads a custom seismic file format.