There are certain situations where you might want to save a
renderer. When you work in load-on-demand mode, for example, only
the parameters necessary for loading the graphic objects in the
layer are saved, not the objects themselves. Load-on-demand is
described in Using load-on-demand.
The complete source code of this example can
be found in the following file:
If the graphic objects are created using a specific renderer, you
must save that renderer to render the objects in the same way the
next time they are loaded. The class IlvSDOLayer, for example, lets you specify a
renderer ( setFeatureRenderer that will be saved with
the layer.
The
ColorLineRenderer
presented in the section Creating a colored line renderer derives from
the
IlvFeatureRenderer
interface, which extends
IlvPersistentObject
and can thus be saved.
/**
* Writes this to specified stream.
*/
public void write(IlvOutputStream stream)
throws java.io.IOException
{
stream.write("attributeName",myAttributeName);
if (myColorModel instanceof IlvPersistentObject)
stream.write("colorModel",(IlvPersistentObject)myColorModel);
else
System.err.println("Warning : colormodel not saved");
}
public ColorLineRenderer(IlvInputStream stream)
throws IlvReadFileException
{
myAttributeName = stream.readString("attributeName");
try {
myColorModel = (ColorModel)stream.readPersistentObject("colorModel");
} catch (IlvFieldNotFoundException e) {
// Get default colormodel
myColorModel = IlvIntervalColorModel.MakeElevationColorModel();
}
}
}