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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

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 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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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

 * {@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

     * {@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

     * {@code getFileSuffixes}, initially {@code null}.

     */

    protected String[] suffixes = null;

    /**

     * An array of strings to be returned from

     * {@code getMIMETypes}, initially {@code null}.

     */

    protected String[] MIMETypes = 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

     * {@code false}.

     */

    protected boolean supportsStandardStreamMetadataFormat = false;

    /**

     * 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 {@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 {@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 {@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

     * {@code false}.

     */

    protected boolean supportsStandardImageMetadataFormat = false;

    /**

     * 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 {@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 {@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 {@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 {@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 {@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 {@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 {@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 {@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

     * {@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 {@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,

     * {@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 {@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 {@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,

     * {@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 {@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