javax.media.jai
Class NullCRIF

java.lang.Object
  javax.media.jai.CRIFImpl
      javax.media.jai.NullCRIF

All Implemented Interfaces:

ContextualRenderedImageFactory, RenderedImageFactory

public class NullCRIF

extends CRIFImpl

A ContextualRenderedImageFactory representing an operation which performs no processing of its image source(s) per se, i.e., a no-op.

The primary use of this image factory is as a utility class in implementing operations which generate only non-image data via the use of PropertyGenerators. A PropertyGenerator is defined as always contributing to the property environment of a given operation when it is returned by the getPropertyGenerators() method of the OperationDescriptor corresponding to the operation.

The procedure to be followed to register an operation which generates only non-image data as JAI image properties is as follows:

• Create a PropertyGenerator which calculates the non-image data given the operation node;
• Create an OperationDescriptor the getPropertyGenerators() method of which returns the PropertyGenerator defined in the previous step;
• Register the OperationDescriptor with the OperationRegistry as usual by passing it to registerOperationDescriptor() along with the operation name;
• Register a NullCRIF as the image factory corresponding to this operation.

The properties emitted by the associated PropertyGenerator(s) will then be available by invoking getProperty() on the node returned by JAI.create() using the registered operation name.

Since:

JAI 1.1

See Also:

CRIFImpl, ContextualRenderedImageFactory

Field Summary

Fields inherited from class javax.media.jai.CRIFImpl

operationName

Constructor Summary

NullCRIF()
Constructs a NullCRIF.

Method Summary

RenderedImage	create(ParameterBlock args, RenderingHints renderHints) Returns the first source in the source list in the ParameterBlock or the value returned by getSourcelessImage() if there are no soures.
static RenderedImage	getSourcelessImage() Gets the value of the RenderedImage to be returned by the RIF.create() method when there are no sources in the ParameterBlock.
static void	setSourcelessImage(RenderedImage im) Sets the value of the RenderedImage to be returned by the RenderedImageFactory.create() method when there are no sources in the ParameterBlock.

Methods inherited from class javax.media.jai.CRIFImpl

create, getBounds2D, getProperty, getPropertyNames, isDynamic, mapRenderContext

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

NullCRIF

public NullCRIF()

Constructs a NullCRIF. The operationName in the superclass is set to null.

Method Detail

setSourcelessImage

public static final void setSourcelessImage(RenderedImage im)

Sets the value of the RenderedImage to be returned by the RenderedImageFactory.create() method when there are no sources in the ParameterBlock.

getSourcelessImage

public static final RenderedImage getSourcelessImage()

Gets the value of the RenderedImage to be returned by the RIF.create() method when there are no sources in the ParameterBlock.

Returns:

a RenderedImage or null.

create

public RenderedImage create(ParameterBlock args,
                            RenderingHints renderHints)

Returns the first source in the source list in the ParameterBlock or the value returned by getSourcelessImage() if there are no soures.

Specified by:

create in interface RenderedImageFactory

Specified by:

create in class CRIFImpl

Throws:

ClassCastException - if there are sources and the source at index zero is not a RenderedImage.