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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));

Fields

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.

Constructors

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

Methods

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

public void setSources(Vector<Object> sources)

Sets the entire Vector of sources to a given Vector.

Parameters:: sources - the Vector of source images
See Also:: getSources()

removeSources

public void removeSources()

Clears the list of source images.

getNumParameters

public int getNumParameters()

Returns the number of parameters (not including source images).

Returns:: the number of parameters in the parameters Vector.

getParameters

public Vector<Object> getParameters()

Returns the entire Vector of parameters.

Returns:: the parameters Vector.
See Also:: setParameters(Vector)

setParameters

public void setParameters(Vector<Object> parameters)

Sets the entire Vector of parameters to a given Vector.

Parameters:: parameters - the specified Vector of parameters
See Also:: getParameters()

removeParameters

public void removeParameters()

Clears the list of parameters.

add

public ParameterBlock add(Object obj)

Adds an object to the list of parameters.

Parameters:: obj - the Object to add to the parameters Vector
Returns:: a new ParameterBlock containing the specified parameter.

add

public ParameterBlock add(byte b)

Adds a Byte to the list of parameters.

Parameters:: b - the byte to add to the parameters Vector
Returns:: a new ParameterBlock containing the specified parameter.

add

public ParameterBlock add(char c)

Adds a Character to the list of parameters.

Parameters:: c - the char to add to the parameters Vector
Returns:: a new ParameterBlock containing the specified parameter.

add

public ParameterBlock add(short s)

Adds a Short to the list of parameters.

Parameters:: s - the short to add to the parameters Vector
Returns:: a new ParameterBlock containing the specified parameter.

add

public ParameterBlock add(int i)

Adds a Integer to the list of parameters.

Parameters:: i - the int to add to the parameters Vector
Returns:: a new ParameterBlock containing the specified parameter.

add

public ParameterBlock add(long l)

Adds a Long to the list of parameters.

Parameters:: l - the long to add to the parameters Vector
Returns:: a new ParameterBlock containing the specified parameter.

add

public ParameterBlock add(float f)

Adds a Float to the list of parameters.

Parameters:: f - the float to add to the parameters Vector
Returns:: a new ParameterBlock containing the specified parameter.

add

public ParameterBlock add(double d)

Adds a Double to the list of parameters.

Parameters:: d - the double to add to the parameters Vector
Returns:: a new ParameterBlock containing the specified parameter.

set

public ParameterBlock set(Object obj,
                          int index)

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

Parameters:: obj - the parameter that replaces the parameter at the specified index in the parameters Vector; index - the index of the parameter to be replaced with the specified parameter
Returns:: a new ParameterBlock containing the specified parameter.

set

public ParameterBlock set(byte b,
                          int index)

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

Parameters:: b - the parameter that replaces the parameter at the specified index in the parameters Vector; index - the index of the parameter to be replaced with the specified parameter
Returns:: a new ParameterBlock containing the specified parameter.

set

public ParameterBlock set(char c,
                          int index)

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

Parameters:: c - the parameter that replaces the parameter at the specified index in the parameters Vector; index - the index of the parameter to be replaced with the specified parameter
Returns:: a new ParameterBlock containing the specified parameter.

set

public ParameterBlock set(short s,
                          int index)

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

Parameters:: s - the parameter that replaces the parameter at the specified index in the parameters Vector; index - the index of the parameter to be replaced with the specified parameter
Returns:: a new ParameterBlock containing the specified parameter.

set

public ParameterBlock set(int i,
                          int index)

Replaces an Object in the list of parameters with an Integer. If the index lies beyond the current source list, the list is extended with nulls as needed.

Parameters:: i - the parameter that replaces the parameter at the specified index in the parameters Vector; index - the index of the parameter to be replaced with the specified parameter
Returns:: a new ParameterBlock containing the specified parameter.

set

public ParameterBlock set(long l,
                          int index)

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

Parameters:: l - the parameter that replaces the parameter at the specified index in the parameters Vector; index - the index of the parameter to be replaced with the specified parameter
Returns:: a new ParameterBlock containing the specified parameter.

set

public ParameterBlock set(float f,
                          int index)

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

Parameters:: f - the parameter that replaces the parameter at the specified index in the parameters Vector; index - the index of the parameter to be replaced with the specified parameter
Returns:: a new ParameterBlock containing the specified parameter.

set

public ParameterBlock set(double d,
                          int index)

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

Parameters:: d - the parameter that replaces the parameter at the specified index in the parameters Vector; index - the index of the parameter to be replaced with the specified parameter
Returns:: a new ParameterBlock containing the specified parameter.

getObjectParameter

public Object getObjectParameter(int index)

Gets a parameter as an object.

Parameters:: index - the index of the parameter to get
Returns:: an Object representing the the parameter at the specified index into the parameters Vector.

getByteParameter

public byte getByteParameter(int index)

A convenience method to return a parameter as a byte. An exception is thrown if the parameter is null or not a Byte.

Parameters:: index - the index of the parameter to be returned.
Returns:: the parameter at the specified index as a byte value.
Throws:: ClassCastException - if the parameter at the specified index is not a Byte; NullPointerException - if the parameter at the specified index is null; ArrayIndexOutOfBoundsException - if index is negative or not less than the current size of this ParameterBlock object

getCharParameter

public char getCharParameter(int index)

A convenience method to return a parameter as a char. An exception is thrown if the parameter is null or not a Character.

Parameters:: index - the index of the parameter to be returned.
Returns:: the parameter at the specified index as a char value.
Throws:: ClassCastException - if the parameter at the specified index is not a Character; NullPointerException - if the parameter at the specified index is null; ArrayIndexOutOfBoundsException - if index is negative or not less than the current size of this ParameterBlock object

getShortParameter

public short getShortParameter(int index)

A convenience method to return a parameter as a short. An exception is thrown if the parameter is null or not a Short.

Parameters:: index - the index of the parameter to be returned.
Returns:: the parameter at the specified index as a short value.
Throws:: ClassCastException - if the parameter at the specified index is not a Short; NullPointerException - if the parameter at the specified index is null; ArrayIndexOutOfBoundsException - if index is negative or not less than the current size of this ParameterBlock object

getIntParameter

public int getIntParameter(int index)

A convenience method to return a parameter as an int. An exception is thrown if the parameter is null or not an Integer.

Parameters:: index - the index of the parameter to be returned.
Returns:: the parameter at the specified index as a int value.
Throws:: ClassCastException - if the parameter at the specified index is not a Integer; NullPointerException - if the parameter at the specified index is null; ArrayIndexOutOfBoundsException - if index is negative or not less than the current size of this ParameterBlock object

getLongParameter

public long getLongParameter(int index)

A convenience method to return a parameter as a long. An exception is thrown if the parameter is null or not a Long.

Parameters:: index - the index of the parameter to be returned.
Returns:: the parameter at the specified index as a long value.
Throws:: ClassCastException - if the parameter at the specified index is not a Long; NullPointerException - if the parameter at the specified index is null; ArrayIndexOutOfBoundsException - if index is negative or not less than the current size of this ParameterBlock object

getFloatParameter

public float getFloatParameter(int index)

A convenience method to return a parameter as a float. An exception is thrown if the parameter is null or not a Float.

Parameters:: index - the index of the parameter to be returned.
Returns:: the parameter at the specified index as a float value.
Throws:: ClassCastException - if the parameter at the specified index is not a Float; NullPointerException - if the parameter at the specified index is null; ArrayIndexOutOfBoundsException - if index is negative or not less than the current size of this ParameterBlock object

getDoubleParameter

public double getDoubleParameter(int index)

A convenience method to return a parameter as a double. An exception is thrown if the parameter is null or not a Double.

Parameters:: index - the index of the parameter to be returned.
Returns:: the parameter at the specified index as a double value.
Throws:: ClassCastException - if the parameter at the specified index is not a Double; NullPointerException - if the parameter at the specified index is null; ArrayIndexOutOfBoundsException - if index is negative or not less than the current size of this ParameterBlock object

getParamClasses

public Class[] getParamClasses()

Returns an array of Class objects describing the types of the parameters.

Returns:: an array of Class objects.

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