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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package javax.imageio.spi;

import java.io.IOException;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Arrays;
import java.util.Iterator;
import javax.imageio.ImageReader;
import javax.imageio.metadata.IIOMetadata;
import javax.imageio.metadata.IIOMetadataFormat;
import javax.imageio.metadata.IIOMetadataFormatImpl;
import javax.imageio.stream.ImageInputStream;


A superclass containing instance variables and methods common to ImageReaderSpi and ImageWriterSpi. 
See Also:
/**
 * A superclass containing instance variables and methods common to
 * {@code ImageReaderSpi} and {@code ImageWriterSpi}.
 *
 * @see IIORegistry
 * @see ImageReaderSpi
 * @see ImageWriterSpi
 *
 */
public abstract class ImageReaderWriterSpi extends IIOServiceProvider {

    
An array of strings to be returned from getFormatNames, initially null. Constructors should set this to a non-null value. 
/**
     * An array of strings to be returned from
     * {@code getFormatNames}, initially {@code null}.
     * Constructors should set this to a non-{@code null} value.
     */
    protected String[] names = null;

    
An array of strings to be returned from getFileSuffixes, initially null. 
/**
     * An array of strings to be returned from
     * {@code getFileSuffixes}, initially {@code null}.
     */
    protected String[] suffixes = null;

    
An array of strings to be returned from getMIMETypes, initially null. 
/**
     * An array of strings to be returned from
     * {@code getMIMETypes}, initially {@code null}.
     */
    protected String[] MIMETypes = null;

    
A String containing the name of the associated plug-in class, initially null. 
/**
     * A {@code String} containing the name of the associated
     * plug-in class, initially {@code null}.
     */
    protected String pluginClassName = null;

    
A boolean indicating whether this plug-in supports the standard metadata format for stream metadata, initially false. 
/**
     * A boolean indicating whether this plug-in supports the
     * standard metadata format for stream metadata, initially
     * {@code false}.
     */
    protected boolean supportsStandardStreamMetadataFormat = false;

    
A String containing the name of the native stream metadata format supported by this plug-in, initially null. 
/**
     * A {@code String} containing the name of the native stream
     * metadata format supported by this plug-in, initially
     * {@code null}.
     */
    protected String nativeStreamMetadataFormatName = null;

    
A String containing the class name of the native stream metadata format supported by this plug-in, initially null. 
/**
     * A {@code String} containing the class name of the native
     * stream metadata format supported by this plug-in, initially
     * {@code null}.
     */
    protected String nativeStreamMetadataFormatClassName = null;

    
An array of Strings containing the names of any additional stream metadata formats supported by this plug-in, initially null. 
/**
     * An array of {@code String}s containing the names of any
     * additional stream metadata formats supported by this plug-in,
     * initially {@code null}.
     */
    protected String[] extraStreamMetadataFormatNames = null;

    
An array of Strings containing the class names of any additional stream metadata formats supported by this plug-in, initially null. 
/**
     * An array of {@code String}s containing the class names of
     * any additional stream metadata formats supported by this plug-in,
     * initially {@code null}.
     */
    protected String[] extraStreamMetadataFormatClassNames = null;

    
A boolean indicating whether this plug-in supports the standard metadata format for image metadata, initially false. 
/**
     * A boolean indicating whether this plug-in supports the
     * standard metadata format for image metadata, initially
     * {@code false}.
     */
    protected boolean supportsStandardImageMetadataFormat = false;

    
A String containing the name of the native stream metadata format supported by this plug-in, initially null. 
/**
     * A {@code String} containing the name of the
     * native stream metadata format supported by this plug-in,
     * initially {@code null}.
     */
    protected String nativeImageMetadataFormatName = null;

    
A String containing the class name of the native stream metadata format supported by this plug-in, initially null. 
/**
     * A {@code String} containing the class name of the
     * native stream metadata format supported by this plug-in,
     * initially {@code null}.
     */
    protected String nativeImageMetadataFormatClassName = null;

    
An array of Strings containing the names of any additional image metadata formats supported by this plug-in, initially null. 
/**
     * An array of {@code String}s containing the names of any
     * additional image metadata formats supported by this plug-in,
     * initially {@code null}.
     */
    protected String[] extraImageMetadataFormatNames = null;

    
An array of Strings containing the class names of any additional image metadata formats supported by this plug-in, initially null. 
/**
     * An array of {@code String}s containing the class names of
     * any additional image metadata formats supported by this
     * plug-in, initially {@code null}.
     */
    protected String[] extraImageMetadataFormatClassNames = null;

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

    
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. 
/**
     * Constructs a blank {@code 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.
     */
    public ImageReaderWriterSpi() {
    }

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

    
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.
/**
     * Returns an array of {@code String}s containing a list of
     * file suffixes associated with the formats that are generally
     * usable by the {@code ImageReader} or
     * {@code ImageWriter} implementation associated with this
     * service provider.  For example, a single
     * {@code 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,
     * {@code null} will be returned.
     *
     * <p> 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 {@code String}s or length at least 1
     * containing common file suffixes associated with this reader or
     * writer, or {@code null}.
     */
    public String[] getFileSuffixes() {
        return suffixes == null ? null : suffixes.clone();
    }

    
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.
/**
     * Returns an array of {@code String}s containing a list of
     * MIME types associated with the formats that are generally
     * usable by the {@code ImageReader} or
     * {@code ImageWriter} implementation associated with this
     * service provider.
     *
     * <p> 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 {@code image/x-pbm} and
     * {@code image/x-portable-bitmap}.  Some file formats have
     * official MIME types but may sometimes be referred to using
     * their previous unofficial designations, such as
     * {@code image/x-png} instead of the official
     * {@code image/png}.  Finally, a single service provider may
     * be capable of parsing multiple distinct types from the MIME
     * point of view, for example {@code image/x-xbitmap} and
     * {@code image/x-xpixmap}.
     *
     * <p> 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 {@code String}s or length at least 1
     * containing MIME types associated with this reader or writer, or
     * {@code null}.
     */
    public String[] getMIMETypes() {
        return MIMETypes == null ? null : MIMETypes.clone();
    }

    
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.
/**
     * Returns the fully-qualified class name of the
     * {@code ImageReader} or {@code ImageWriter} plug-in
     * associated with this service provider.
     *
     * @return the class name, as a non-{@code null}
     * {@code String}.
     */
    public String getPluginClassName() {
        return pluginClassName;
    }

    
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.
/**
     * Returns {@code true} if the standard metadata format is
     * among the document formats recognized by the
     * {@code getAsTree} and {@code setFromTree} methods on
     * the stream metadata objects produced or consumed by this
     * plug-in.
     *
     * @return {@code true} if the standard format is supported
     * for stream metadata.
     */
    public boolean isStandardStreamMetadataFormatSupported() {
        return supportsStandardStreamMetadataFormat;
    }

    
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.
/**
     * 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,
     * {@code null} will be returned.
     *
     * <p> The default implementation returns the
     * {@code nativeStreamMetadataFormatName} instance variable,
     * which is typically set by the constructor.
     *
     * @return the name of the native stream metadata format, or
     * {@code null}.
     *
     */
    public String getNativeStreamMetadataFormatName() {
        return nativeStreamMetadataFormatName;
    }

    
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. 
See Also:
Returns:an array of Strings, or null.
/**
     * Returns an array of {@code String}s containing the names
     * of additional document formats, other than the native and
     * standard formats, recognized by the
     * {@code getAsTree} and {@code setFromTree} methods on
     * the stream metadata objects produced or consumed by this
     * plug-in.
     *
     * <p> If the plug-in does not handle metadata, null should be
     * returned.
     *
     * <p> 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.
     *
     * <p> The default implementation returns a clone of the
     * {@code extraStreamMetadataFormatNames} instance variable,
     * which is typically set by the constructor.
     *
     * @return an array of {@code String}s, or null.
     *
     * @see IIOMetadata#getMetadataFormatNames
     * @see #getExtraImageMetadataFormatNames
     * @see #getNativeStreamMetadataFormatName
     */
    public String[] getExtraStreamMetadataFormatNames() {
        return extraStreamMetadataFormatNames == null ?
            null : extraStreamMetadataFormatNames.clone();
    }

    
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.
/**
     * Returns {@code true} if the standard metadata format is
     * among the document formats recognized by the
     * {@code getAsTree} and {@code setFromTree} methods on
     * the image metadata objects produced or consumed by this
     * plug-in.
     *
     * @return {@code true} if the standard format is supported
     * for image metadata.
     */
    public boolean isStandardImageMetadataFormatSupported() {
        return supportsStandardImageMetadataFormat;
    }

    
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. 
See Also:
Returns:the name of the native image metadata format, or null.
/**
     * 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,
     * {@code null} will be returned.
     *
     * <p> The default implementation returns the
     * {@code nativeImageMetadataFormatName} instance variable,
     * which is typically set by the constructor.
     *
     * @return the name of the native image metadata format, or
     * {@code null}.
     *
     * @see #getExtraImageMetadataFormatNames
     */
    public String getNativeImageMetadataFormatName() {
        return nativeImageMetadataFormatName;
    }

    
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. 
See Also:
Returns:an array of Strings, or null.
/**
     * Returns an array of {@code String}s containing the names
     * of additional document formats, other than the native and
     * standard formats, recognized by the
     * {@code getAsTree} and {@code setFromTree} methods on
     * the image metadata objects produced or consumed by this
     * plug-in.
     *
     * <p> If the plug-in does not handle image metadata, null should
     * be returned.
     *
     * <p> 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.
     *
     * <p> The default implementation returns a clone of the
     * {@code extraImageMetadataFormatNames} instance variable,
     * which is typically set by the constructor.
     *
     * @return an array of {@code String}s, or null.
     *
     * @see IIOMetadata#getMetadataFormatNames
     * @see #getExtraStreamMetadataFormatNames
     * @see #getNativeImageMetadataFormatName
     */
    public String[] getExtraImageMetadataFormatNames() {
        return extraImageMetadataFormatNames == null ?
            null : extraImageMetadataFormatNames.clone();
    }

    
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. 
Params:
  • formatName – the desired stream metadata format.
Throws:
Returns:an IIOMetadataFormat object.
/**
     * Returns an {@code IIOMetadataFormat} object describing the
     * given stream metadata format, or {@code 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
     * {@code getExtraStreamMetadataFormatNames}.
     *
     * @param formatName the desired stream metadata format.
     *
     * @return an {@code IIOMetadataFormat} object.
     *
     * @exception IllegalArgumentException if {@code formatName}
     * is {@code null} or is not a supported name.
     */
    public IIOMetadataFormat getStreamMetadataFormat(String formatName) {
        return getMetadataFormat(formatName,
                                 supportsStandardStreamMetadataFormat,
                                 nativeStreamMetadataFormatName,
                                 nativeStreamMetadataFormatClassName,
                                 extraStreamMetadataFormatNames,
                                 extraStreamMetadataFormatClassNames);
    }

    
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. 
Params:
  • formatName – the desired image metadata format.
Throws:
Returns:an IIOMetadataFormat object.
/**
     * Returns an {@code IIOMetadataFormat} object describing the
     * given image metadata format, or {@code 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
     * {@code getExtraImageMetadataFormatNames}.
     *
     * @param formatName the desired image metadata format.
     *
     * @return an {@code IIOMetadataFormat} object.
     *
     * @exception IllegalArgumentException if {@code formatName}
     * is {@code null} or is not a supported name.
     */
    public IIOMetadataFormat getImageMetadataFormat(String formatName) {
        return getMetadataFormat(formatName,
                                 supportsStandardImageMetadataFormat,
                                 nativeImageMetadataFormatName,
                                 nativeImageMetadataFormatClassName,
                                 extraImageMetadataFormatNames,
                                 extraImageMetadataFormatClassNames);
    }

    private IIOMetadataFormat getMetadataFormat(String formatName,
                                                boolean supportsStandard,
                                                String nativeName,
                                                String nativeClassName,
                                                String [] extraNames,
                                                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 {
            // Try to load from the same location as the module of the SPI
            final String className = formatClassName;
            PrivilegedAction<Class<?>> pa = () -> { return getMetadataFormatClass(className); };
            Class<?> cls = AccessController.doPrivileged(pa);
            Method meth = cls.getMethod("getInstance");
            return (IIOMetadataFormat) meth.invoke(null);
        } catch (Exception e) {
            RuntimeException ex =
                new IllegalStateException ("Can't obtain format");
            ex.initCause(e);
            throw ex;
        }
    }

    // If updating this method also see the same in IIOMetadata.java
    private Class<?> getMetadataFormatClass(String formatClassName) {
        Module thisModule = ImageReaderWriterSpi.class.getModule();
        Module targetModule = this.getClass().getModule();
        Class<?> c = null;
        try {
            ClassLoader cl = this.getClass().getClassLoader();
            c = Class.forName(formatClassName, false, cl);
            if (!IIOMetadataFormat.class.isAssignableFrom(c)) {
                return null;
            }
        } catch (ClassNotFoundException e) {
        }
        if (thisModule.equals(targetModule) || c == null) {
            return c;
        }
        if (targetModule.isNamed()) {
            int i = formatClassName.lastIndexOf(".");
            String pn = i > 0 ? formatClassName.substring(0, i) : "";
            if (!targetModule.isExported(pn, thisModule)) {
                throw new IllegalStateException("Class " +  formatClassName +
                  " in named module must be exported to java.desktop module.");
            }
        }
        return c;
    }
}