java.awt.image.renderable
Class ParameterBlock

java.lang.Object   
  java.awt.image.renderable.ParameterBlock

All Implemented Interfaces:

Serializable , Cloneable

public class ParameterBlock
extends Object   
implements Cloneable   , Serializable   

A ParameterBlock encapsulates all the information about sources and parameters (Objects) required by a RenderableImageOp, or other classes that process images.

Although it is possible to place arbitrary objects in the source Vector, users of this class may impose semantic constraints such as requiring all sources to be RenderedImages or RenderableImage. ParameterBlock itself is merely a container and performs no checking on source or parameter types.

All parameters in a ParameterBlock are objects; convenience add and set methods are available that take arguments of base type and construct the appropriate subclass of Number (such as Integer or Float). Corresponding get methods perform a downward cast and have return values of base type; an exception will be thrown if the stored values do not have the correct type. There is no way to distinguish between the results of "short s; add(s)" and "add(new Short(s))".

Note that the get and set methods operate on references. Therefore, one must be careful not to share references between ParameterBlocks when this is inappropriate. For example, to create a new ParameterBlock that is equal to an old one except for an added source, one might be tempted to write:

 ParameterBlock addSource(ParameterBlock pb, RenderableImage im) {
     ParameterBlock pb1 = new ParameterBlock(pb.getSources());
     pb1.addSource(im);
     return pb1;
 }
 

This code will have the side effect of altering the original ParameterBlock, since the getSources operation returned a reference to its source Vector. Both pb and pb1 share their source Vector, and a change in either is visible to both.

A correct way to write the addSource function is to clone the source Vector:

 ParameterBlock addSource (ParameterBlock pb, RenderableImage im) {
     ParameterBlock pb1 = new ParameterBlock(pb.getSources().clone());
     pb1.addSource(im);
     return pb1;
 }
 

The clone method of ParameterBlock has been defined to perform a clone of both the source and parameter Vectors for this reason. A standard, shallow clone is available as shallowClone.

The addSource, setSource, add, and set methods are defined to return 'this' after adding their argument. This allows use of syntax like:

 ParameterBlock pb = new ParameterBlock();
 op = new RenderableImageOp("operation", pb.add(arg1).add(arg2));
 

See Also:

Serialized Form

Field Summary

protected Vector <Object >	parameters A Vector of non-source parameters, stored as arbitrary Objects.
protected Vector <Object >	sources A Vector of sources, stored as arbitrary Objects.

Constructor Summary

ParameterBlock ()
A dummy constructor.

ParameterBlock (Vector <Object > sources)
Constructs a ParameterBlock with a given Vector of sources.

ParameterBlock (Vector <Object > sources, Vector <Object > parameters)
Constructs a ParameterBlock with a given Vector of sources and Vector of parameters.

Method Summary

ParameterBlock	add (byte b) Adds a Byte to the list of parameters.
ParameterBlock	add (char c) Adds a Character to the list of parameters.
ParameterBlock	add (double d) Adds a Double to the list of parameters.
ParameterBlock	add (float f) Adds a Float to the list of parameters.
ParameterBlock	add (int i) Adds a Integer to the list of parameters.
ParameterBlock	add (long l) Adds a Long to the list of parameters.
ParameterBlock	add (Object obj) Adds an object to the list of parameters.
ParameterBlock	add (short s) Adds a Short to the list of parameters.
ParameterBlock	addSource (Object source) Adds an image to end of the list of sources.
Object	clone () Creates a copy of a ParameterBlock.
byte	getByteParameter (int index) A convenience method to return a parameter as a byte.
char	getCharParameter (int index) A convenience method to return a parameter as a char.
double	getDoubleParameter (int index) A convenience method to return a parameter as a double.
float	getFloatParameter (int index) A convenience method to return a parameter as a float.
int	getIntParameter (int index) A convenience method to return a parameter as an int.
long	getLongParameter (int index) A convenience method to return a parameter as a long.
int	getNumParameters () Returns the number of parameters (not including source images).
int	getNumSources () Returns the number of source images.
Object	getObjectParameter (int index) Gets a parameter as an object.
Class []	getParamClasses () Returns an array of Class objects describing the types of the parameters.
Vector <Object >	getParameters () Returns the entire Vector of parameters.
RenderableImage	getRenderableSource (int index) Returns a source as a RenderableImage.
RenderedImage	getRenderedSource (int index) Returns a source as a RenderedImage.
short	getShortParameter (int index) A convenience method to return a parameter as a short.
Object	getSource (int index) Returns a source as a general Object.
Vector <Object >	getSources () Returns the entire Vector of sources.
void	removeParameters () Clears the list of parameters.
void	removeSources () Clears the list of source images.
ParameterBlock	set (byte b, int index) Replaces an Object in the list of parameters with a Byte.
ParameterBlock	set (char c, int index) Replaces an Object in the list of parameters with a Character.
ParameterBlock	set (double d, int index) Replaces an Object in the list of parameters with a Double.
ParameterBlock	set (float f, int index) Replaces an Object in the list of parameters with a Float.
ParameterBlock	set (int i, int index) Replaces an Object in the list of parameters with an Integer.
ParameterBlock	set (long l, int index) Replaces an Object in the list of parameters with a Long.
ParameterBlock	set (Object obj, int index) Replaces an Object in the list of parameters.
ParameterBlock	set (short s, int index) Replaces an Object in the list of parameters with a Short.
void	setParameters (Vector <Object > parameters) Sets the entire Vector of parameters to a given Vector.
ParameterBlock	setSource (Object source, int index) Replaces an entry in the list of source with a new source.
void	setSources (Vector <Object > sources) Sets the entire Vector of sources to a given Vector.
Object	shallowClone () Creates a shallow copy of a ParameterBlock.

Methods inherited from class java.lang.Object

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

Field Detail

sources

protected Vector   <Object   > sources

A Vector of sources, stored as arbitrary Objects.

parameters

protected Vector   <Object   > parameters

A Vector of non-source parameters, stored as arbitrary Objects.

Constructor Detail

ParameterBlock

public ParameterBlock()

A dummy constructor.

ParameterBlock

public ParameterBlock(Vector   <Object   > sources)

Constructs a ParameterBlock with a given Vector of sources.

Parameters:

sources - a Vector of source images

ParameterBlock

public ParameterBlock(Vector   <Object   > sources,
                      Vector   <Object   > parameters)

Constructs a ParameterBlock with a given Vector of sources and Vector of parameters.

Parameters:

sources - a Vector of source images

parameters - a Vector of parameters to be used in the rendering operation

Method Detail

shallowClone

public Object    shallowClone()

Creates a shallow copy of a ParameterBlock. The source and parameter Vectors are copied by reference -- additions or changes will be visible to both versions.

Returns:

an Object clone of the ParameterBlock.

clone

public Object    clone()

Creates a copy of a ParameterBlock. The source and parameter Vectors are cloned, but the actual sources and parameters are copied by reference. This allows modifications to the order and number of sources and parameters in the clone to be invisible to the original ParameterBlock. Changes to the shared sources or parameters themselves will still be visible.

Overrides:

clone in class Object

Returns:

an Object clone of the ParameterBlock.

See Also:

Cloneable

addSource

public ParameterBlock    addSource(Object    source)

Adds an image to end of the list of sources. The image is stored as an object in order to allow new node types in the future.

Parameters:

source - an image object to be stored in the source list.

Returns:

a new ParameterBlock containing the specified source.

getSource

public Object    getSource(int index)

Returns a source as a general Object. The caller must cast it into an appropriate type.

Parameters:

index - the index of the source to be returned.

Returns:

an Object that represents the source located at the specified index in the sources Vector.

See Also:

setSource(Object, int)

setSource

public ParameterBlock    setSource(Object    source,
                                int index)

Replaces an entry in the list of source with a new source. If the index lies beyond the current source list, the list is extended with nulls as needed.

Parameters:

source - the specified source image

index - the index into the sources Vector at which to insert the specified source

Returns:

a new ParameterBlock that contains the specified source at the specified index.

See Also:

getSource(int)

getRenderedSource

public RenderedImage    getRenderedSource(int index)

Returns a source as a RenderedImage. This method is a convenience method. An exception will be thrown if the source is not a RenderedImage.

Parameters:

index - the index of the source to be returned

Returns:

a RenderedImage that represents the source image that is at the specified index in the sources Vector.

getRenderableSource

public RenderableImage    getRenderableSource(int index)

Returns a source as a RenderableImage. This method is a convenience method. An exception will be thrown if the sources is not a RenderableImage.

Parameters:

index - the index of the source to be returned

Returns:

a RenderableImage that represents the source image that is at the specified index in the sources Vector.

getNumSources

public int getNumSources()

Returns the number of source images.

Returns:

the number of source images in the sources Vector.

getSources

public Vector   <Object   > getSources()

Returns the entire Vector of sources.

Returns:

the sources Vector.

See Also:

setSources(Vector)

setSources