javax.media.jai.operator
Class FileLoadDescriptor

java.lang.Object
  javax.media.jai.OperationDescriptorImpl
      javax.media.jai.operator.FileLoadDescriptor

All Implemented Interfaces:

OperationDescriptor, RegistryElementDescriptor, Serializable

public class FileLoadDescriptor

extends OperationDescriptorImpl

An OperationDescriptor describing the "FileLoad" operation.

In the default instance the validateParameters() method checks that the named file exists and is readable. If not, it will return false, causing JAI.createNS() to throw an IllegalArgumentException. In special cases like when an image is loaded from a Remote system, the above check for existence of a file on the local system could be bypassed. This is done by setting the Boolean variable checkFileLocally to FALSE in the ParameterBlock

The allowable formats are those registered with the com.sun.media.jai.codec.ImageCodec class.

The second parameter contains an instance of ImageDecodeParam to be used during the decoding. It may be set to null in order to perform default decoding, or equivalently may be omitted.

The classes in the com.sun.media.jai.codec package are not a committed part of the JAI API. Future releases of JAI will make use of new classes in their place. This class will change accordingly.

Resource List

Name	Value
GlobalName	fileload
LocalName	fileload
Vendor	com.sun.media.jai
Description	Reads an image from a file.
DocURL	http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/operator/FileLoadDescriptor.html
Version	1.0
arg0Desc	The path of the file to read from.
arg1Desc	The ImageDecodeParam to use.
arg2Desc	Boolean specifying if File existence should be checked locally.

Parameter List

Name	Class Type	Default Value
filename	java.lang.String	NO_PARAMETER_DEFAULT
param	com.sun.media.jai.codec.ImageDecodeParam	null
checkFileLocally	java.lang.Boolean	TRUE

See Also:

OperationDescriptor, Serialized Form

Field Summary

Fields inherited from class javax.media.jai.OperationDescriptorImpl

sourceNames, supportedModes

Fields inherited from interface javax.media.jai.OperationDescriptor

NO_PARAMETER_DEFAULT

Constructor Summary

FileLoadDescriptor()
Constructor.

Method Summary

static RenderedOp	create(String filename, ImageDecodeParam param, Boolean checkFileLocally, RenderingHints hints) Reads an image from a file.
protected boolean	validateParameters(ParameterBlock args, StringBuffer msg) Validates the input parameters.

Methods inherited from class javax.media.jai.OperationDescriptorImpl

arePropertiesSupported, getDefaultSourceClass, getDestClass, getDestClass, getInvalidRegion, getName, getNumParameters, getNumSources, getParamClasses, getParamDefaults, getParamDefaultValue, getParameterListDescriptor, getParamMaxValue, getParamMinValue, getParamNames, getPropertyGenerators, getPropertyGenerators, getRenderableDestClass, getRenderableSourceClasses, getResourceBundle, getResources, getSourceClasses, getSourceClasses, getSourceNames, getSupportedModes, isImmediate, isModeSupported, isRenderableSupported, isRenderedSupported, makeDefaultSourceClassList, validateArguments, validateArguments, validateParameters, validateRenderableArguments, validateRenderableSources, validateSources, validateSources

Methods inherited from class java.lang.Object

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

Constructor Detail

FileLoadDescriptor

public FileLoadDescriptor()

Constructor.

Method Detail

validateParameters

protected boolean validateParameters(ParameterBlock args,
                                     StringBuffer msg)

Validates the input parameters.

In addition to the standard checks performed by the superclass method, this method by default checks that the source file exists and is readable. This check may be bypassed by setting the checkFileLocally parameter to FALSE

Overrides:

validateParameters in class OperationDescriptorImpl

See Also:

OperationDescriptorImpl.validateParameters(java.lang.String, java.awt.image.renderable.ParameterBlock, java.lang.StringBuffer)

create

public static RenderedOp create(String filename,
                                ImageDecodeParam param,
                                Boolean checkFileLocally,
                                RenderingHints hints)

Reads an image from a file.

Creates a ParameterBlockJAI from all supplied arguments except hints and invokes JAI.create(String,ParameterBlock,RenderingHints).

Parameters:

filename - The path of the file to read from.

param - The ImageDecodeParam to use. May be null.

checkFileLocally - Boolean specifying if File existence should be checked locally May be null.

hints - The RenderingHints to use. May be null.

Returns:

The RenderedOp destination.

Throws:

IllegalArgumentException - if filename is null.

See Also:

JAI, ParameterBlockJAI, RenderedOp