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ImageReaderWriterSpi.javaAPI DocJava SE 5 API24637Fri Aug 26 14:57:30 BST 2005javax.imageio.spi

ImageReaderWriterSpi

public abstract class ImageReaderWriterSpi extends IIOServiceProvider
A superclass containing instance variables and methods common to ImageReaderSpi and ImageWriterSpi.
see
IIORegistry
see
ImageReaderSpi
see
ImageWriterSpi
version
0.5

Fields Summary
protected String[]
names
An array of strings to be returned from getFormatNames, initially null. Constructors should set this to a non-null value.
protected String[]
suffixes
An array of strings to be returned from getFileSuffixes, initially null.
protected String[]
MIMETypes
An array of strings to be returned from getMIMETypes, initially null.
protected String
pluginClassName
A String containing the name of the associated plug-in class, initially null.
protected boolean
supportsStandardStreamMetadataFormat
A boolean indicating whether this plug-in supports the standard metadata format for stream metadata, initially false.
protected String
nativeStreamMetadataFormatName
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[]
extraStreamMetadataFormatNames
An array of Strings containing the names of any additional stream 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 boolean
supportsStandardImageMetadataFormat
A boolean indicating whether this plug-in supports the standard metadata format for image metadata, initially false.
protected String
nativeImageMetadataFormatName
A String containing the name of the native stream metadata format supported by this plug-in, 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[]
extraImageMetadataFormatNames
An array of Strings containing the names of any additional image metadata formats supported by this plug-in, initially null.
protected String[]
extraImageMetadataFormatClassNames
An array of Strings containing the class names of any additional image metadata formats supported by this plug-in, initially null.
Constructors Summary
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.

param
vendorName the vendor name, as a non-null String.
param
version a version identifier, as a non-null String.
param
names a non-null array of Strings indicating the format names. At least one entry must be present.
param
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.
param
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.
param
pluginClassName the fully-qualified name of the associated ImageReader or ImageWriter class, as a non-null String.
param
supportsStandardStreamMetadataFormat a boolean that indicates whether a stream metadata object can use trees described by the standard metadata format.
param
nativeStreamMetadataFormatName a String, or null, to be returned from getNativeStreamMetadataFormatName.
param
nativeStreamMetadataFormatClassName a String, or null, to be used to instantiate a metadata format object to be returned from getNativeStreamMetadataFormat.
param
extraStreamMetadataFormatNames an array of Strings, or null, to be returned from getExtraStreamMetadataFormatNames. An array of length 0 is normalized to null.
param
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.
param
supportsStandardImageMetadataFormat a boolean that indicates whether an image metadata object can use trees described by the standard metadata format.
param
nativeImageMetadataFormatName a String, or null, to be returned from getNativeImageMetadataFormatName.
param
nativeImageMetadataFormatClassName a String, or null, to be used to instantiate a metadata format object to be returned from getNativeImageMetadataFormat.
param
extraImageMetadataFormatNames an array of Strings to be returned from getExtraImageMetadataFormatNames. An array of length 0 is normalized to null.
param
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.
exception
IllegalArgumentException if vendorName is null.
exception
IllegalArgumentException if version is null.
exception
IllegalArgumentException if names is null or has length 0.
exception
IllegalArgumentException if pluginClassName is null.


                                                                                                                                                                                                                                                                                                                                                                                       
      
                                 
                                 
                                 
                                 
                                 
                                 
                                 
                                 
                                 
                                 
                                 
                                 
                                 
                                 
                                  
        super(vendorName, version);
        if (names == null) {
            throw new IllegalArgumentException("names == null!");
        }
        if (names.length == 0) {
            throw new IllegalArgumentException("names.length == 0!");
        }
        if (pluginClassName == null) {
            throw new IllegalArgumentException("pluginClassName == null!");
        }

        this.names = (String[])names.clone();
        // If length == 0, leave it null
        if (suffixes != null && suffixes.length > 0) {
            this.suffixes = (String[])suffixes.clone();
        }
        // If length == 0, leave it null
        if (MIMETypes != null && MIMETypes.length > 0) {
            this.MIMETypes = (String[])MIMETypes.clone();
        }
        this.pluginClassName = pluginClassName;

        this.supportsStandardStreamMetadataFormat = 
            supportsStandardStreamMetadataFormat;
        this.nativeStreamMetadataFormatName = nativeStreamMetadataFormatName;
        this.nativeStreamMetadataFormatClassName = 
            nativeStreamMetadataFormatClassName;
        // If length == 0, leave it null
        if (extraStreamMetadataFormatNames != null &&
            extraStreamMetadataFormatNames.length > 0) {
            this.extraStreamMetadataFormatNames =
                (String[])extraStreamMetadataFormatNames.clone();
        }
        // If length == 0, leave it null
        if (extraStreamMetadataFormatClassNames != null &&
            extraStreamMetadataFormatClassNames.length > 0) {
            this.extraStreamMetadataFormatClassNames =
                (String[])extraStreamMetadataFormatClassNames.clone();
        }
        this.supportsStandardImageMetadataFormat = 
            supportsStandardImageMetadataFormat;
        this.nativeImageMetadataFormatName = nativeImageMetadataFormatName;
        this.nativeImageMetadataFormatClassName = 
            nativeImageMetadataFormatClassName;
        // If length == 0, leave it null
        if (extraImageMetadataFormatNames != null &&
            extraImageMetadataFormatNames.length > 0) {
            this.extraImageMetadataFormatNames =
                (String[])extraImageMetadataFormatNames.clone();
        }
        // If length == 0, leave it null
        if (extraImageMetadataFormatClassNames != null &&
            extraImageMetadataFormatClassNames.length > 0) {
            this.extraImageMetadataFormatClassNames =
                (String[])extraImageMetadataFormatClassNames.clone();
        }
    
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.

    
Methods Summary
public java.lang.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.

return
an array of Strings, or null.
see
IIOMetadata#getMetadataFormatNames
see
#getExtraStreamMetadataFormatNames
see
#getNativeImageMetadataFormatName

        return extraImageMetadataFormatNames == null ?
            null : (String[])extraImageMetadataFormatNames.clone();
    
public java.lang.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.

return
an array of Strings, or null.
see
IIOMetadata#getMetadataFormatNames
see
#getExtraImageMetadataFormatNames
see
#getNativeStreamMetadataFormatName

        return extraStreamMetadataFormatNames == null ?
            null : (String[])extraStreamMetadataFormatNames.clone();
    
public java.lang.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.

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

        return suffixes == null ? null : (String[])suffixes.clone();
    
public java.lang.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.

return
a non-null array of Strings or length at least 1 containing informal format names associated with this reader or writer.

        return (String[])names.clone();
    
public javax.imageio.metadata.IIOMetadataFormatgetImageMetadataFormat(java.lang.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 iamge metadata format name, the standard metadata format name, or one of those returned by getExtraImageMetadataFormatNames.

param
formatName the desired image metadata format.
return
an IIOMetadataFormat object.
exception
IllegalArgumentException if formatName is null or is not a supported name.

        return getMetadataFormat(formatName,
                                 supportsStandardImageMetadataFormat,
                                 nativeImageMetadataFormatName,
                                 nativeImageMetadataFormatClassName,
                                 extraImageMetadataFormatNames,
                                 extraImageMetadataFormatClassNames);
    
public java.lang.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.

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

        return MIMETypes == null ? null : (String[])MIMETypes.clone();
    
private javax.imageio.metadata.IIOMetadataFormatgetMetadataFormat(java.lang.String formatName, boolean supportsStandard, java.lang.String nativeName, java.lang.String nativeClassName, java.lang.String[] extraNames, java.lang.String[] extraClassNames)

        if (formatName == null) {
            throw new IllegalArgumentException("formatName == null!");
        }
        if (supportsStandard && formatName.equals
                (IIOMetadataFormatImpl.standardMetadataFormatName)) {

            return IIOMetadataFormatImpl.getStandardFormatInstance();
        }
        String formatClassName = null;
        if (formatName.equals(nativeName)) {
            formatClassName = nativeClassName; 
        } else if (extraNames != null) {
            for (int i = 0; i < extraNames.length; i++) {
                if (formatName.equals(extraNames[i])) {
                    formatClassName = extraClassNames[i];
                    break;  // out of for
                }
            }
        }
        if (formatClassName == null) {
            throw new IllegalArgumentException("Unsupported format name");
        }
        try {
            Class cls = Class.forName(formatClassName, true,
                                      ClassLoader.getSystemClassLoader());
            Method meth = cls.getMethod("getInstance", null);
            return (IIOMetadataFormat) meth.invoke(null, null);
        } catch (Exception e) {
            RuntimeException ex = 
                new IllegalStateException ("Can't obtain format");
            ex.initCause(e);
            throw ex;
        }
    
public java.lang.StringgetNativeImageMetadataFormatName()
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, nullwill be returned.

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

return
the name of the native image metadata format, or null.
see
#getExtraImageMetadataFormatNames

        return nativeImageMetadataFormatName;
    
public java.lang.StringgetNativeStreamMetadataFormatName()
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, nullwill be returned.

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

return
the name of the native stream metadata format, or null.

        return nativeStreamMetadataFormatName;
    
public java.lang.StringgetPluginClassName()
Returns the fully-qualified class name of the ImageReader or ImageWriter plug-in associated with this service provider.

return
the class name, as a non-null String.

        return pluginClassName;
    
public javax.imageio.metadata.IIOMetadataFormatgetStreamMetadataFormat(java.lang.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.

param
formatName the desired stream metadata format.
return
an IIOMetadataFormat object.
exception
IllegalArgumentException if formatName is null or is not a supported name.

        return getMetadataFormat(formatName,
                                 supportsStandardStreamMetadataFormat,
                                 nativeStreamMetadataFormatName,
                                 nativeStreamMetadataFormatClassName,
                                 extraStreamMetadataFormatNames,
                                 extraStreamMetadataFormatClassNames);
    
public booleanisStandardImageMetadataFormatSupported()
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.

return
true if the standard format is supported for image metadata.

        return supportsStandardImageMetadataFormat;
    
public booleanisStandardStreamMetadataFormatSupported()
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.

return
true if the standard format is supported for stream metadata.

        return supportsStandardStreamMetadataFormat;