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/OpenJDK 21

Class ImageReaderWriterSpi

java.lang.Object
javax.imageio.spi.IIOServiceProvider
javax.imageio.spi.ImageReaderWriterSpi
All Implemented Interfaces:
RegisterableService
Direct Known Subclasses:
ImageReaderSpi, ImageWriterSpi 
public abstract class ImageReaderWriterSpi extends IIOServiceProvider
A superclass containing instance variables and methods common to ImageReaderSpi and ImageWriterSpi.
See Also:

Field Summary

Modifier and Type Field Description
protected String[] extraImageMetadataFormatClassNames
An array of Strings containing the class names of any additional image metadata formats supported by this plug-in, initially null.
protected String[] extraImageMetadataFormatNames
An array of Strings containing the names of any additional image metadata formats supported by this plug-in, initially null.
protected String[] extraStreamMetadataFormatClassNames
An array of Strings containing the class names of any additional stream metadata formats supported by this plug-in, initially null.
protected String[] extraStreamMetadataFormatNames
An array of Strings containing the names of any additional stream metadata formats supported by this plug-in, initially null.
protected String[] MIMETypes
An array of strings to be returned from getMIMETypes, initially null.
protected String[] names
An array of strings to be returned from getFormatNames, initially null.
protected String nativeImageMetadataFormatClassName
A String containing the class name of the native stream metadata format supported by this plug-in, initially null.
protected String nativeImageMetadataFormatName
A String containing the name of the native stream metadata format supported by this plug-in, initially null.
protected String nativeStreamMetadataFormatClassName
A String containing the class name of the native stream metadata format supported by this plug-in, initially null.
protected String nativeStreamMetadataFormatName
A String containing the name of the native stream metadata format supported by this plug-in, initially null.
protected String pluginClassName
A String containing the name of the associated plug-in class, initially null.
protected String[] suffixes
An array of strings to be returned from getFileSuffixes, initially null.
protected boolean supportsStandardImageMetadataFormat
A boolean indicating whether this plug-in supports the standard metadata format for image metadata, initially false.
protected boolean supportsStandardStreamMetadataFormat
A boolean indicating whether this plug-in supports the standard metadata format for stream metadata, initially false.

Fields declared in class javax.imageio.spi.IIOServiceProvider

vendorName, version

Constructor Summary

Constructor Description
ImageReaderWriterSpi()
Constructs a blank ImageReaderWriterSpi.
ImageReaderWriterSpi(String vendorName, String version, String[] names, String[] suffixes, String[] MIMETypes, String pluginClassName, boolean supportsStandardStreamMetadataFormat, String nativeStreamMetadataFormatName, String nativeStreamMetadataFormatClassName, String[] extraStreamMetadataFormatNames, String[] extraStreamMetadataFormatClassNames, boolean supportsStandardImageMetadataFormat, String nativeImageMetadataFormatName, String nativeImageMetadataFormatClassName, String[] extraImageMetadataFormatNames, String[] extraImageMetadataFormatClassNames)
Constructs an ImageReaderWriterSpi with a given set of values.

Method Summary

Modifier and Type Method Description
String[] getExtraImageMetadataFormatNames()
Returns an array of Strings containing the names of additional document formats, other than the native and standard formats, recognized by the getAsTree and setFromTree methods on the image metadata objects produced or consumed by this plug-in.
String[] getExtraStreamMetadataFormatNames()
Returns an array of Strings containing the names of additional document formats, other than the native and standard formats, recognized by the getAsTree and setFromTree methods on the stream metadata objects produced or consumed by this plug-in.
String[] getFileSuffixes()
Returns an array of Strings containing a list of file suffixes associated with the formats that are generally usable by the ImageReader or ImageWriter implementation associated with this service provider.
String[] getFormatNames()
Returns an array of Strings containing human-readable names for the formats that are generally usable by the ImageReader or ImageWriter implementation associated with this service provider.
IIOMetadataFormat getImageMetadataFormat(String formatName)
Returns an IIOMetadataFormat object describing the given image metadata format, or null if no description is available.
String[] getMIMETypes()
Returns an array of Strings containing a list of MIME types associated with the formats that are generally usable by the ImageReader or ImageWriter implementation associated with this service provider.
String getNativeImageMetadataFormatName()
Returns the name of the "native" image metadata format for this plug-in, which typically allows for lossless encoding and transmission of the image metadata stored in the format handled by this plug-in.
String getNativeStreamMetadataFormatName()
Returns the name of the "native" stream metadata format for this plug-in, which typically allows for lossless encoding and transmission of the stream metadata stored in the format handled by this plug-in.
String getPluginClassName()
Returns the fully-qualified class name of the ImageReader or ImageWriter plug-in associated with this service provider.
IIOMetadataFormat getStreamMetadataFormat(String formatName)
Returns an IIOMetadataFormat object describing the given stream metadata format, or null if no description is available.
boolean isStandardImageMetadataFormatSupported()
Returns true if the standard metadata format is among the document formats recognized by the getAsTree and setFromTree methods on the image metadata objects produced or consumed by this plug-in.
boolean isStandardStreamMetadataFormatSupported()
Returns true if the standard metadata format is among the document formats recognized by the getAsTree and setFromTree methods on the stream metadata objects produced or consumed by this plug-in.

Methods declared in class javax.imageio.spi.IIOServiceProvider

getDescription, getVendorName, getVersion, onDeregistration, onRegistration

Methods declared in class java.lang.Object

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

Field Details

names

protected String[] names
An array of strings to be returned from getFormatNames, initially null. Constructors should set this to a non-null value.

suffixes

protected String[] suffixes
An array of strings to be returned from getFileSuffixes, initially null.

MIMETypes

protected String[] MIMETypes
An array of strings to be returned from getMIMETypes, initially null.

pluginClassName

protected String pluginClassName
A String containing the name of the associated plug-in class, initially null.

supportsStandardStreamMetadataFormat

protected boolean supportsStandardStreamMetadataFormat
A boolean indicating whether this plug-in supports the standard metadata format for stream metadata, initially false.

nativeStreamMetadataFormatName

protected String nativeStreamMetadataFormatName
A String containing the name of the native stream metadata format supported by this plug-in, initially null.

nativeStreamMetadataFormatClassName

protected String nativeStreamMetadataFormatClassName
A String containing the class name of the native stream metadata format supported by this plug-in, initially null.

extraStreamMetadataFormatNames

protected String[] extraStreamMetadataFormatNames
An array of Strings containing the names of any additional stream metadata formats supported by this plug-in, initially null.

extraStreamMetadataFormatClassNames

protected String[] extraStreamMetadataFormatClassNames
An array of Strings containing the class names of any additional stream metadata formats supported by this plug-in, initially null.

supportsStandardImageMetadataFormat

protected boolean supportsStandardImageMetadataFormat
A boolean indicating whether this plug-in supports the standard metadata format for image metadata, initially false.

nativeImageMetadataFormatName

protected String nativeImageMetadataFormatName
A String containing the name of the native stream metadata format supported by this plug-in, initially null.

nativeImageMetadataFormatClassName

protected String nativeImageMetadataFormatClassName
A String containing the class name of the native stream metadata format supported by this plug-in, initially null.

extraImageMetadataFormatNames

protected String[] extraImageMetadataFormatNames
An array of Strings containing the names of any additional image metadata formats supported by this plug-in, initially null.

extraImageMetadataFormatClassNames

protected String[] extraImageMetadataFormatClassNames
An array of Strings containing the class names of any additional image metadata formats supported by this plug-in, initially null.

Constructor Details

ImageReaderWriterSpi

public ImageReaderWriterSpi(String vendorName, String version, String[] names, String[] suffixes, String[] MIMETypes, String pluginClassName, boolean supportsStandardStreamMetadataFormat, String nativeStreamMetadataFormatName, String nativeStreamMetadataFormatClassName, String[] extraStreamMetadataFormatNames, String[] extraStreamMetadataFormatClassNames, boolean supportsStandardImageMetadataFormat, String nativeImageMetadataFormatName, String nativeImageMetadataFormatClassName, String[] extraImageMetadataFormatNames, String[] extraImageMetadataFormatClassNames)
Constructs an ImageReaderWriterSpi with a given set of values.
Parameters:
vendorName - the vendor name, as a non-null String.
version - a version identifier, as a non-null String.
names - a non-null array of Strings indicating the format names. At least one entry must be present.
suffixes - an array of Strings indicating the common file suffixes. If no suffixes are defined, null should be supplied. An array of length 0 will be normalized to null.
MIMETypes - an array of Strings indicating the format's MIME types. If no MIME types are defined, null should be supplied. An array of length 0 will be normalized to null.
pluginClassName - the fully-qualified name of the associated ImageReader or ImageWriter class, as a non-null String.
supportsStandardStreamMetadataFormat - a boolean that indicates whether a stream metadata object can use trees described by the standard metadata format.
nativeStreamMetadataFormatName - a String, or null, to be returned from getNativeStreamMetadataFormatName.
nativeStreamMetadataFormatClassName - a String, or null, to be used to instantiate a metadata format object to be returned from getNativeStreamMetadataFormat.
extraStreamMetadataFormatNames - an array of Strings, or null, to be returned from getExtraStreamMetadataFormatNames. An array of length 0 is normalized to null.
extraStreamMetadataFormatClassNames - an array of Strings, or null, to be used to instantiate a metadata format object to be returned from getStreamMetadataFormat. An array of length 0 is normalized to null.
supportsStandardImageMetadataFormat - a boolean that indicates whether an image metadata object can use trees described by the standard metadata format.
nativeImageMetadataFormatName - a String, or null, to be returned from getNativeImageMetadataFormatName.
nativeImageMetadataFormatClassName - a String, or null, to be used to instantiate a metadata format object to be returned from getNativeImageMetadataFormat.
extraImageMetadataFormatNames - an array of Strings to be returned from getExtraImageMetadataFormatNames. An array of length 0 is normalized to null.
extraImageMetadataFormatClassNames - an array of Strings, or null, to be used to instantiate a metadata format object to be returned from getImageMetadataFormat. An array of length 0 is normalized to null.
Throws:
IllegalArgumentException - if vendorName is null.
IllegalArgumentException - if version is null.
IllegalArgumentException - if names is null or has length 0.
IllegalArgumentException - if pluginClassName is null.

ImageReaderWriterSpi

public ImageReaderWriterSpi()
Constructs a blank ImageReaderWriterSpi. It is up to the subclass to initialize instance variables and/or override method implementations in order to provide working versions of all methods.

Method Details

getFormatNames

public String[] getFormatNames()
Returns an array of Strings containing human-readable names for the formats that are generally usable by the ImageReader or ImageWriter implementation associated with this service provider. For example, a single ImageReader might be able to process both PBM and PNM files.
Returns:
a non-null array of Strings or length at least 1 containing informal format names associated with this reader or writer.

getFileSuffixes

public String[] getFileSuffixes()
Returns an array of Strings containing a list of file suffixes associated with the formats that are generally usable by the ImageReader or ImageWriter implementation associated with this service provider. For example, a single ImageReader might be able to process files with '.pbm' and '.pnm' suffixes, or both '.jpg' and '.jpeg' suffixes. If there are no known file suffixes, null will be returned.

Returning a particular suffix does not guarantee that files with that suffix can be processed; it merely indicates that it may be worthwhile attempting to decode or encode such files using this service provider.

Returns:
an array of Strings or length at least 1 containing common file suffixes associated with this reader or writer, or null.

getMIMETypes

public String[] getMIMETypes()
Returns an array of Strings containing a list of MIME types associated with the formats that are generally usable by the ImageReader or ImageWriter implementation associated with this service provider.

Ideally, only a single MIME type would be required in order to describe a particular format. However, for several reasons it is necessary to associate a list of types with each service provider. First, many common image file formats do not have standard MIME types, so a list of commonly used unofficial names will be required, such as image/x-pbm and image/x-portable-bitmap. Some file formats have official MIME types but may sometimes be referred to using their previous unofficial designations, such as image/x-png instead of the official image/png. Finally, a single service provider may be capable of parsing multiple distinct types from the MIME point of view, for example image/x-xbitmap and image/x-xpixmap.

Returning a particular MIME type does not guarantee that files claiming to be of that type can be processed; it merely indicates that it may be worthwhile attempting to decode or encode such files using this service provider.

Returns:
an array of Strings or length at least 1 containing MIME types associated with this reader or writer, or null.

getPluginClassName

public String getPluginClassName()
Returns the fully-qualified class name of the ImageReader or ImageWriter plug-in associated with this service provider.
Returns:
the class name, as a non-null String.

isStandardStreamMetadataFormatSupported

public boolean isStandardStreamMetadataFormatSupported()
Returns true if the standard metadata format is among the document formats recognized by the getAsTree and setFromTree methods on the stream metadata objects produced or consumed by this plug-in.
Returns:
true if the standard format is supported for stream metadata.

getNativeStreamMetadataFormatName

public String getNativeStreamMetadataFormatName()
Returns the name of the "native" stream metadata format for this plug-in, which typically allows for lossless encoding and transmission of the stream metadata stored in the format handled by this plug-in. If no such format is supported, null will be returned.

The default implementation returns the nativeStreamMetadataFormatName instance variable, which is typically set by the constructor.

Returns:
the name of the native stream metadata format, or null.

getExtraStreamMetadataFormatNames

public String[] getExtraStreamMetadataFormatNames()
Returns an array of Strings containing the names of additional document formats, other than the native and standard formats, recognized by the getAsTree and setFromTree methods on the stream metadata objects produced or consumed by this plug-in.

If the plug-in does not handle metadata, null should be returned.

The set of formats may differ according to the particular images being read or written; this method should indicate all the additional formats supported by the plug-in under any circumstances.

The default implementation returns a clone of the extraStreamMetadataFormatNames instance variable, which is typically set by the constructor.

Returns:
an array of Strings, or null.
See Also:

isStandardImageMetadataFormatSupported

public boolean isStandardImageMetadataFormatSupported()
Returns true if the standard metadata format is among the document formats recognized by the getAsTree and setFromTree methods on the image metadata objects produced or consumed by this plug-in.
Returns:
true if the standard format is supported for image metadata.

getNativeImageMetadataFormatName

public String getNativeImageMetadataFormatName()
Returns the name of the "native" image metadata format for this plug-in, which typically allows for lossless encoding and transmission of the image metadata stored in the format handled by this plug-in. If no such format is supported, null will be returned.

The default implementation returns the nativeImageMetadataFormatName instance variable, which is typically set by the constructor.

Returns:
the name of the native image metadata format, or null.
See Also:

getExtraImageMetadataFormatNames

public String[] getExtraImageMetadataFormatNames()
Returns an array of Strings containing the names of additional document formats, other than the native and standard formats, recognized by the getAsTree and setFromTree methods on the image metadata objects produced or consumed by this plug-in.

If the plug-in does not handle image metadata, null should be returned.

The set of formats may differ according to the particular images being read or written; this method should indicate all the additional formats supported by the plug-in under any circumstances.

The default implementation returns a clone of the extraImageMetadataFormatNames instance variable, which is typically set by the constructor.

Returns:
an array of Strings, or null.
See Also:

getStreamMetadataFormat

public IIOMetadataFormat getStreamMetadataFormat(String formatName)
Returns an IIOMetadataFormat object describing the given stream metadata format, or null if no description is available. The supplied name must be the native stream metadata format name, the standard metadata format name, or one of those returned by getExtraStreamMetadataFormatNames.
Parameters:
formatName - the desired stream metadata format.
Returns:
an IIOMetadataFormat object.
Throws:
IllegalArgumentException - if formatName is null or is not a supported name.

getImageMetadataFormat

public IIOMetadataFormat getImageMetadataFormat(String formatName)
Returns an IIOMetadataFormat object describing the given image metadata format, or null if no description is available. The supplied name must be the native image metadata format name, the standard metadata format name, or one of those returned by getExtraImageMetadataFormatNames.
Parameters:
formatName - the desired image metadata format.
Returns:
an IIOMetadataFormat object.
Throws:
IllegalArgumentException - if formatName is null or is not a supported name.

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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/javax/imageio/spi/ImageReaderWriterSpi.html