package gr.iti.mklab.visual.utilities;
/*
* %W% %E%
*
* Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
import java.awt.image.BufferedImage;
import java.awt.image.RenderedImage;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.Method;
import java.net.URL;
import java.security.AccessController;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import javax.imageio.IIOException;
import javax.imageio.ImageReadParam;
import javax.imageio.ImageReader;
import javax.imageio.ImageTranscoder;
import javax.imageio.ImageTypeSpecifier;
import javax.imageio.ImageWriter;
import javax.imageio.spi.IIORegistry;
import javax.imageio.spi.ImageInputStreamSpi;
import javax.imageio.spi.ImageOutputStreamSpi;
import javax.imageio.spi.ImageReaderSpi;
import javax.imageio.spi.ImageReaderWriterSpi;
import javax.imageio.spi.ImageTranscoderSpi;
import javax.imageio.spi.ImageWriterSpi;
import javax.imageio.spi.ServiceRegistry;
import javax.imageio.stream.ImageInputStream;
import javax.imageio.stream.ImageOutputStream;
import sun.awt.AppContext;
import sun.security.action.GetPropertyAction;
/**
* A class containing static convenience methods for locating <code>ImageReader</code>s and
* <code>ImageWriter</code>s, and performing simple encoding and decoding.
*
* @version 0.5
*/
public final class ImageIOGreyScale {
private static final IIORegistry theRegistry = IIORegistry.getDefaultInstance();
/**
* Constructor is private to prevent instantiation.
*/
private ImageIOGreyScale() {
}
/**
* Scans for plug-ins on the application class path, loads their service provider classes, and registers a
* service provider instance for each one found with the <code>IIORegistry</code>.
*
* <p>
* This method is needed because the application class path can theoretically change, or additional
* plug-ins may become available. Rather than re-scanning the classpath on every invocation of the API,
* the class path is scanned automatically only on the first invocation. Clients can call this method to
* prompt a re-scan. Thus this method need only be invoked by sophisticated applications which dynamically
* make new plug-ins available at runtime.
*
* <p>
* The <code>getResources</code> method of the context <code>ClassLoader</code> is used locate JAR files
* containing files named <code>META-INF/services/javax.imageio.spi.</code><i>classname</i>, where
* <i>classname</i> is one of <code>ImageReaderSpi</code>, <code>ImageWriterSpi</code>,
* <code>ImageTranscoderSpi</code>, <code>ImageInputStreamSpi</code>, or <code>ImageOutputStreamSpi</code>
* , along the application class path.
*
* <p>
* The contents of the located files indicate the names of actual implementation classes which implement
* the aforementioned service provider interfaces; the default class loader is then used to load each of
* these classes and to instantiate an instance of each class, which is then placed into the registry for
* later retrieval.
*
* <p>
* The exact set of locations searched depends on the implementation of the Java runtime enviroment.
*
* @see ClassLoader#getResources
*/
public static void scanForPlugins() {
theRegistry.registerApplicationClasspathSpis();
}
// ImageInputStreams
/**
* A class to hold information about caching. Each <code>ThreadGroup</code> will have its own copy via the
* <code>AppContext</code> mechanism.
*/
static class CacheInfo {
boolean useCache = true;
File cacheDirectory = null;
Boolean hasPermission = null;
public CacheInfo() {
}
public boolean getUseCache() {
return useCache;
}
public void setUseCache(boolean useCache) {
this.useCache = useCache;
}
public File getCacheDirectory() {
return cacheDirectory;
}
public void setCacheDirectory(File cacheDirectory) {
this.cacheDirectory = cacheDirectory;
}
public Boolean getHasPermission() {
return hasPermission;
}
public void setHasPermission(Boolean hasPermission) {
this.hasPermission = hasPermission;
}
}
/**
* Returns the <code>CacheInfo</code> object associated with this <code>ThreadGroup</code>.
*/
private static synchronized CacheInfo getCacheInfo() {
AppContext context = AppContext.getAppContext();
CacheInfo info = (CacheInfo) context.get(CacheInfo.class);
if (info == null) {
info = new CacheInfo();
context.put(CacheInfo.class, info);
}
return info;
}
/**
* Returns the default temporary (cache) directory as defined by the java.io.tmpdir system property.
*/
private static String getTempDir() {
GetPropertyAction a = new GetPropertyAction("java.io.tmpdir");
return (String) AccessController.doPrivileged(a);
}
/**
* Determines whether the caller has write access to the cache directory, stores the result in the
* <code>CacheInfo</code> object, and returns the decision. This method helps to prevent mysterious
* SecurityExceptions to be thrown when this convenience class is used in an applet, for example.
*/
private static boolean hasCachePermission() {
Boolean hasPermission = getCacheInfo().getHasPermission();
if (hasPermission != null) {
return hasPermission.booleanValue();
} else {
try {
SecurityManager security = System.getSecurityManager();
if (security != null) {
File cachedir = getCacheDirectory();
String cachepath;
if (cachedir != null) {
cachepath = cachedir.getPath();
} else {
cachepath = getTempDir();
if (cachepath == null) {
getCacheInfo().setHasPermission(Boolean.FALSE);
return false;
}
}
security.checkWrite(cachepath);
}
} catch (SecurityException e) {
getCacheInfo().setHasPermission(Boolean.FALSE);
return false;
}
getCacheInfo().setHasPermission(Boolean.TRUE);
return true;
}
}
/**
* Sets a flag indicating whether a disk-based cache file should be used when creating
* <code>ImageInputStream</code>s and <code>ImageOutputStream</code>s.
*
* <p>
* When reading from a standard <code>InputStream</code>>, it may be necessary to save previously read
* information in a cache since the underlying stream does not allow data to be re-read. Similarly, when
* writing to a standard <code>OutputStream</code>, a cache may be used to allow a previously written
* value to be changed before flushing it to the final destination.
*
* <p>
* The cache may reside in main memory or on disk. Setting this flag to <code>false</code> disallows the
* use of disk for future streams, which may be advantageous when working with small images, as the
* overhead of creating and destroying files is removed.
*
* <p>
* On startup, the value is set to <code>true</code>.
*
* @param useCache
* a <code>boolean</code> indicating whether a cache file should be used, in cases where it is
* optional.
*
* @see #getUseCache
*/
public static void setUseCache(boolean useCache) {
getCacheInfo().setUseCache(useCache);
}
/**
* Returns the current value set by <code>setUseCache</code>, or <code>true</code> if no explicit setting
* has been made.
*
* @return true if a disk-based cache may be used for <code>ImageInputStream</code>s and
* <code>ImageOutputStream</code>s.
*
* @see #setUseCache
*/
public static boolean getUseCache() {
return getCacheInfo().getUseCache();
}
/**
* Sets the directory where cache files are to be created. A value of <code>null</code> indicates that the
* system-dependent default temporary-file directory is to be used. If <code>getUseCache</code> returns
* false, this value is ignored.
*
* @param cacheDirectory
* a <code>File</code> specifying a directory.
*
* @see File#createTempFile(String, String, File)
*
* @exception SecurityException
* if the security manager denies access to the directory.
* @exception IllegalArgumentException
* if <code>cacheDir</code> is non-<code>null</code> but is not a directory.
*
* @see #getCacheDirectory
*/
public static void setCacheDirectory(File cacheDirectory) {
if ((cacheDirectory != null) && !(cacheDirectory.isDirectory())) {
throw new IllegalArgumentException("Not a directory!");
}
getCacheInfo().setCacheDirectory(cacheDirectory);
getCacheInfo().setHasPermission(null);
}
/**
* Returns the current value set by <code>setCacheDirectory</code>, or <code>null</code> if no explicit
* setting has been made.
*
* @return a <code>File</code> indicating the directory where cache files will be created, or
* <code>null</code> to indicate the system-dependent default temporary-file directory.
*
* @see #setCacheDirectory
*/
public static File getCacheDirectory() {
return getCacheInfo().getCacheDirectory();
}
/**
* Returns an <code>ImageInputStream</code> that will take its input from the given <code>Object</code>.
* The set of <code>ImageInputStreamSpi</code>s registered with the <code>IIORegistry</code> class is
* queried and the first one that is able to take input from the supplied object is used to create the
* returned <code>ImageInputStream</code>. If no suitable <code>ImageInputStreamSpi</code> exists,
* <code>null</code> is returned.
*
* <p>
* The current cache settings from <code>getUseCache</code>and <code>getCacheDirectory</code> will be used
* to control caching.
*
* @param input
* an <code>Object</code> to be used as an input source, such as a <code>File</code>, readable
* <code>RandomAccessFile</code>, or <code>InputStream</code>.
*
* @return an <code>ImageInputStream</code>, or <code>null</code>.
*
* @exception IllegalArgumentException
* if <code>input</code> is <code>null</code>.
* @exception IOException
* if a cache file is needed but cannot be created.
*
* @see javax.imageio.spi.ImageInputStreamSpi
*/
public static ImageInputStream createImageInputStream(Object input) throws IOException {
if (input == null) {
throw new IllegalArgumentException("input == null!");
}
Iterator iter;
// Ensure category is present
try {
iter = theRegistry.getServiceProviders(ImageInputStreamSpi.class, true);
} catch (IllegalArgumentException e) {
return null;
}
boolean usecache = getUseCache() && hasCachePermission();
while (iter.hasNext()) {
ImageInputStreamSpi spi = (ImageInputStreamSpi) iter.next();
if (spi.getInputClass().isInstance(input)) {
try {
return spi.createInputStreamInstance(input, usecache, getCacheDirectory());
} catch (IOException e) {
throw new IIOException("Can't create cache file!", e);
}
}
}
return null;
}
// ImageOutputStreams
/**
* Returns an <code>ImageOutputStream</code> that will send its output to the given <code>Object</code>.
* The set of <code>ImageOutputStreamSpi</code>s registered with the <code>IIORegistry</code> class is
* queried and the first one that is able to send output from the supplied object is used to create the
* returned <code>ImageOutputStream</code>. If no suitable <code>ImageOutputStreamSpi</code> exists,
* <code>null</code> is returned.
*
* <p>
* The current cache settings from <code>getUseCache</code>and <code>getCacheDirectory</code> will be used
* to control caching.
*
* @param output
* an <code>Object</code> to be used as an output destination, such as a <code>File</code>,
* writable <code>RandomAccessFile</code>, or <code>OutputStream</code>.
*
* @return an <code>ImageOutputStream</code>, or <code>null</code>.
*
* @exception IllegalArgumentException
* if <code>output</code> is <code>null</code>.
* @exception IOException
* if a cache file is needed but cannot be created.
*
* @see javax.imageio.spi.ImageOutputStreamSpi
*/
public static ImageOutputStream createImageOutputStream(Object output) throws IOException {
if (output == null) {
throw new IllegalArgumentException("output == null!");
}
Iterator iter;
// Ensure category is present
try {
iter = theRegistry.getServiceProviders(ImageOutputStreamSpi.class, true);
} catch (IllegalArgumentException e) {
return null;
}
boolean usecache = getUseCache() && hasCachePermission();
while (iter.hasNext()) {
ImageOutputStreamSpi spi = (ImageOutputStreamSpi) iter.next();
if (spi.getOutputClass().isInstance(output)) {
try {
return spi.createOutputStreamInstance(output, usecache, getCacheDirectory());
} catch (IOException e) {
throw new IIOException("Can't create cache file!", e);
}
}
}
return null;
}
private static enum SpiInfo {
FORMAT_NAMES {
@Override
String[] info(ImageReaderWriterSpi spi) {
return spi.getFormatNames();
}
},
MIME_TYPES {
@Override
String[] info(ImageReaderWriterSpi spi) {
return spi.getMIMETypes();
}
},
FILE_SUFFIXES {
@Override
String[] info(ImageReaderWriterSpi spi) {
return spi.getFileSuffixes();
}
};
abstract String[] info(ImageReaderWriterSpi spi);
}
private static <S extends ImageReaderWriterSpi> String[] getReaderWriterInfo(Class<S> spiClass, SpiInfo spiInfo) {
// Ensure category is present
Iterator<S> iter;
try {
iter = theRegistry.getServiceProviders(spiClass, true);
} catch (IllegalArgumentException e) {
return new String[0];
}
HashSet<String> s = new HashSet<String>();
while (iter.hasNext()) {
ImageReaderWriterSpi spi = iter.next();
Collections.addAll(s, spiInfo.info(spi));
}
return s.toArray(new String[s.size()]);
}
// Readers
/**
* Returns an array of <code>String</code>s listing all of the informal format names understood by the
* current set of registered readers.
*
* @return an array of <code>String</code>s.
*/
public static String[] getReaderFormatNames() {
return getReaderWriterInfo(ImageReaderSpi.class, SpiInfo.FORMAT_NAMES);
}
/**
* Returns an array of <code>String</code>s listing all of the MIME types understood by the current set of
* registered readers.
*
* @return an array of <code>String</code>s.
*/
public static String[] getReaderMIMETypes() {
return getReaderWriterInfo(ImageReaderSpi.class, SpiInfo.MIME_TYPES);
}
/**
* Returns an array of <code>String</code>s listing all of the file suffixes associated with the formats
* understood by the current set of registered readers.
*
* @return an array of <code>String</code>s.
* @since 1.6
*/
public static String[] getReaderFileSuffixes() {
return getReaderWriterInfo(ImageReaderSpi.class, SpiInfo.FILE_SUFFIXES);
}
static class ImageReaderIterator implements Iterator<ImageReader> {
// Contains ImageReaderSpis
public Iterator iter;
public ImageReaderIterator(Iterator iter) {
this.iter = iter;
}
public boolean hasNext() {
return iter.hasNext();
}
public ImageReader next() {
ImageReaderSpi spi = null;
try {
spi = (ImageReaderSpi) iter.next();
return spi.createReaderInstance();
} catch (IOException e) {
// Deregister the spi in this case, but only as
// an ImageReaderSpi
theRegistry.deregisterServiceProvider(spi, ImageReaderSpi.class);
}
return null;
}
public void remove() {
throw new UnsupportedOperationException();
}
}
static class CanDecodeInputFilter implements ServiceRegistry.Filter {
Object input;
public CanDecodeInputFilter(Object input) {
this.input = input;
}
public boolean filter(Object elt) {
try {
ImageReaderSpi spi = (ImageReaderSpi) elt;
ImageInputStream stream = null;
if (input instanceof ImageInputStream) {
stream = (ImageInputStream) input;
}
// Perform mark/reset as a defensive measure
// even though plug-ins are supposed to take
// care of it.
boolean canDecode = false;
if (stream != null) {
stream.mark();
}
canDecode = spi.canDecodeInput(input);
if (stream != null) {
stream.reset();
}
return canDecode;
} catch (IOException e) {
return false;
}
}
}
static class CanEncodeImageAndFormatFilter implements ServiceRegistry.Filter {
ImageTypeSpecifier type;
String formatName;
public CanEncodeImageAndFormatFilter(ImageTypeSpecifier type, String formatName) {
this.type = type;
this.formatName = formatName;
}
public boolean filter(Object elt) {
ImageWriterSpi spi = (ImageWriterSpi) elt;
return Arrays.asList(spi.getFormatNames()).contains(formatName) && spi.canEncodeImage(type);
}
}
static class ContainsFilter implements ServiceRegistry.Filter {
Method method;
String name;
// method returns an array of Strings
public ContainsFilter(Method method, String name) {
this.method = method;
this.name = name;
}
public boolean filter(Object elt) {
try {
return contains((String[]) method.invoke(elt), name);
} catch (Exception e) {
return false;
}
}
}
/**
* Returns an <code>Iterator</code> containing all currently registered <code>ImageReader</code>s that
* claim to be able to decode the supplied <code>Object</code>, typically an <code>ImageInputStream</code>
* .
*
* <p>
* The stream position is left at its prior position upon exit from this method.
*
* @param input
* an <code>ImageInputStream</code> or other <code>Object</code> containing encoded image data.
*
* @return an <code>Iterator</code> containing <code>ImageReader</code>s.
*
* @exception IllegalArgumentException
* if <code>input</code> is <code>null</code>.
*
* @see javax.imageio.spi.ImageReaderSpi#canDecodeInput
*/
public static Iterator<ImageReader> getImageReaders(Object input) {
if (input == null) {
throw new IllegalArgumentException("input == null!");
}
Iterator iter;
// Ensure category is present
try {
iter = theRegistry.getServiceProviders(ImageReaderSpi.class, new CanDecodeInputFilter(input), true);
} catch (IllegalArgumentException e) {
return new HashSet().iterator();
}
return new ImageReaderIterator(iter);
}
private static Method readerFormatNamesMethod;
private static Method readerFileSuffixesMethod;
private static Method readerMIMETypesMethod;
private static Method writerFormatNamesMethod;
private static Method writerFileSuffixesMethod;
private static Method writerMIMETypesMethod;
static {
try {
readerFormatNamesMethod = ImageReaderSpi.class.getMethod("getFormatNames");
readerFileSuffixesMethod = ImageReaderSpi.class.getMethod("getFileSuffixes");
readerMIMETypesMethod = ImageReaderSpi.class.getMethod("getMIMETypes");
writerFormatNamesMethod = ImageWriterSpi.class.getMethod("getFormatNames");
writerFileSuffixesMethod = ImageWriterSpi.class.getMethod("getFileSuffixes");
writerMIMETypesMethod = ImageWriterSpi.class.getMethod("getMIMETypes");
} catch (NoSuchMethodException e) {
e.printStackTrace();
}
}
/**
* Returns an <code>Iterator</code> containing all currently registered <code>ImageReader</code>s that
* claim to be able to decode the named format.
*
* @param formatName
* a <code>String</code> containing the informal name of a format (<i>e.g.</i>, "jpeg" or
* "tiff".
*
* @return an <code>Iterator</code> containing <code>ImageReader</code>s.
*
* @exception IllegalArgumentException
* if <code>formatName</code> is <code>null</code>.
*
* @see javax.imageio.spi.ImageReaderSpi#getFormatNames
*/
public static Iterator<ImageReader> getImageReadersByFormatName(String formatName) {
if (formatName == null) {
throw new IllegalArgumentException("formatName == null!");
}
Iterator iter;
// Ensure category is present
try {
iter = theRegistry.getServiceProviders(ImageReaderSpi.class, new ContainsFilter(readerFormatNamesMethod, formatName), true);
} catch (IllegalArgumentException e) {
return new HashSet().iterator();
}
return new ImageReaderIterator(iter);
}
/**
* Returns an <code>Iterator</code> containing all currently registered <code>ImageReader</code>s that
* claim to be able to decode files with the given suffix.
*
* @param fileSuffix
* a <code>String</code> containing a file suffix (<i>e.g.</i>, "jpg" or "tiff").
*
* @return an <code>Iterator</code> containing <code>ImageReader</code>s.
*
* @exception IllegalArgumentException
* if <code>fileSuffix</code> is <code>null</code>.
*
* @see javax.imageio.spi.ImageReaderSpi#getFileSuffixes
*/
public static Iterator<ImageReader> getImageReadersBySuffix(String fileSuffix) {
if (fileSuffix == null) {
throw new IllegalArgumentException("fileSuffix == null!");
}
// Ensure category is present
Iterator iter;
try {
iter = theRegistry.getServiceProviders(ImageReaderSpi.class, new ContainsFilter(readerFileSuffixesMethod, fileSuffix), true);
} catch (IllegalArgumentException e) {
return new HashSet().iterator();
}
return new ImageReaderIterator(iter);
}
/**
* Returns an <code>Iterator</code> containing all currently registered <code>ImageReader</code>s that
* claim to be able to decode files with the given MIME type.
*
* @param MIMEType
* a <code>String</code> containing a file suffix (<i>e.g.</i>, "image/jpeg" or "image/x-bmp").
*
* @return an <code>Iterator</code> containing <code>ImageReader</code>s.
*
* @exception IllegalArgumentException
* if <code>MIMEType</code> is <code>null</code>.
*
* @see javax.imageio.spi.ImageReaderSpi#getMIMETypes
*/
public static Iterator<ImageReader> getImageReadersByMIMEType(String MIMEType) {
if (MIMEType == null) {
throw new IllegalArgumentException("MIMEType == null!");
}
// Ensure category is present
Iterator iter;
try {
iter = theRegistry.getServiceProviders(ImageReaderSpi.class, new ContainsFilter(readerMIMETypesMethod, MIMEType), true);
} catch (IllegalArgumentException e) {
return new HashSet().iterator();
}
return new ImageReaderIterator(iter);
}
// Writers
/**
* Returns an array of <code>String</code>s listing all of the informal format names understood by the
* current set of registered writers.
*
* @return an array of <code>String</code>s.
*/
public static String[] getWriterFormatNames() {
return getReaderWriterInfo(ImageWriterSpi.class, SpiInfo.FORMAT_NAMES);
}
/**
* Returns an array of <code>String</code>s listing all of the MIME types understood by the current set of
* registered writers.
*
* @return an array of <code>String</code>s.
*/
public static String[] getWriterMIMETypes() {
return getReaderWriterInfo(ImageWriterSpi.class, SpiInfo.MIME_TYPES);
}
/**
* Returns an array of <code>String</code>s listing all of the file suffixes associated with the formats
* understood by the current set of registered writers.
*
* @return an array of <code>String</code>s.
* @since 1.6
*/
public static String[] getWriterFileSuffixes() {
return getReaderWriterInfo(ImageWriterSpi.class, SpiInfo.FILE_SUFFIXES);
}
static class ImageWriterIterator implements Iterator<ImageWriter> {
// Contains ImageWriterSpis
public Iterator iter;
public ImageWriterIterator(Iterator iter) {
this.iter = iter;
}
public boolean hasNext() {
return iter.hasNext();
}
public ImageWriter next() {
ImageWriterSpi spi = null;
try {
spi = (ImageWriterSpi) iter.next();
return spi.createWriterInstance();
} catch (IOException e) {
// Deregister the spi in this case, but only as a writerSpi
theRegistry.deregisterServiceProvider(spi, ImageWriterSpi.class);
}
return null;
}
public void remove() {
throw new UnsupportedOperationException();
}
}
private static boolean contains(String[] names, String name) {
for (int i = 0; i < names.length; i++) {
if (name.equalsIgnoreCase(names[i])) {
return true;
}
}
return false;
}
/**
* Returns an <code>Iterator</code> containing all currently registered <code>ImageWriter</code>s that
* claim to be able to encode the named format.
*
* @param formatName
* a <code>String</code> containing the informal name of a format (<i>e.g.</i>, "jpeg" or
* "tiff".
*
* @return an <code>Iterator</code> containing <code>ImageWriter</code>s.
*
* @exception IllegalArgumentException
* if <code>formatName</code> is <code>null</code>.
*
* @see javax.imageio.spi.ImageWriterSpi#getFormatNames
*/
public static Iterator<ImageWriter> getImageWritersByFormatName(String formatName) {
if (formatName == null) {
throw new IllegalArgumentException("formatName == null!");
}
Iterator iter;
// Ensure category is present
try {
iter = theRegistry.getServiceProviders(ImageWriterSpi.class, new ContainsFilter(writerFormatNamesMethod, formatName), true);
} catch (IllegalArgumentException e) {
return new HashSet().iterator();
}
return new ImageWriterIterator(iter);
}
/**
* Returns an <code>Iterator</code> containing all currently registered <code>ImageWriter</code>s that
* claim to be able to encode files with the given suffix.
*
* @param fileSuffix
* a <code>String</code> containing a file suffix (<i>e.g.</i>, "jpg" or "tiff").
*
* @return an <code>Iterator</code> containing <code>ImageWriter</code>s.
*
* @exception IllegalArgumentException
* if <code>fileSuffix</code> is <code>null</code>.
*
* @see javax.imageio.spi.ImageWriterSpi#getFileSuffixes
*/
public static Iterator<ImageWriter> getImageWritersBySuffix(String fileSuffix) {
if (fileSuffix == null) {
throw new IllegalArgumentException("fileSuffix == null!");
}
Iterator iter;
// Ensure category is present
try {
iter = theRegistry.getServiceProviders(ImageWriterSpi.class, new ContainsFilter(writerFileSuffixesMethod, fileSuffix), true);
} catch (IllegalArgumentException e) {
return new HashSet().iterator();
}
return new ImageWriterIterator(iter);
}
/**
* Returns an <code>Iterator</code> containing all currently registered <code>ImageWriter</code>s that
* claim to be able to encode files with the given MIME type.
*
* @param MIMEType
* a <code>String</code> containing a file suffix (<i>e.g.</i>, "image/jpeg" or "image/x-bmp").
*
* @return an <code>Iterator</code> containing <code>ImageWriter</code>s.
*
* @exception IllegalArgumentException
* if <code>MIMEType</code> is <code>null</code>.
*
* @see javax.imageio.spi.ImageWriterSpi#getMIMETypes
*/
public static Iterator<ImageWriter> getImageWritersByMIMEType(String MIMEType) {
if (MIMEType == null) {
throw new IllegalArgumentException("MIMEType == null!");
}
Iterator iter;
// Ensure category is present
try {
iter = theRegistry.getServiceProviders(ImageWriterSpi.class, new ContainsFilter(writerMIMETypesMethod, MIMEType), true);
} catch (IllegalArgumentException e) {
return new HashSet().iterator();
}
return new ImageWriterIterator(iter);
}
/**
* Returns an <code>ImageWriter</code>corresponding to the given <code>ImageReader</code>, if there is
* one, or <code>null</code> if the plug-in for this <code>ImageReader</code> does not specify a
* corresponding <code>ImageWriter</code>, or if the given <code>ImageReader</code> is not registered.
* This mechanism may be used to obtain an <code>ImageWriter</code> that will understand the internal
* structure of non-pixel metadata (as encoded by <code>IIOMetadata</code> objects) generated by the
* <code>ImageReader</code>. By obtaining this data from the <code>ImageReader</code> and passing it on to
* the <code>ImageWriter</code> obtained with this method, a client program can read an image, modify it
* in some way, and write it back out preserving all metadata, without having to understand anything about
* the structure of the metadata, or even about the image format. Note that this method returns the
* "preferred" writer, which is the first in the list returned by
* <code>javax.imageio.spi.ImageReaderSpi.getImageWriterSpiNames()</code>.
*
* @param reader
* an instance of a registered <code>ImageReader</code>.
*
* @return an <code>ImageWriter</code>, or null.
*
* @exception IllegalArgumentException
* if <code>reader</code> is <code>null</code>.
*
* @see #getImageReader(ImageWriter)
* @see javax.imageio.spi.ImageReaderSpi#getImageWriterSpiNames()
*/
public static ImageWriter getImageWriter(ImageReader reader) {
if (reader == null) {
throw new IllegalArgumentException("reader == null!");
}
ImageReaderSpi readerSpi = reader.getOriginatingProvider();
if (readerSpi == null) {
Iterator readerSpiIter;
// Ensure category is present
try {
readerSpiIter = theRegistry.getServiceProviders(ImageReaderSpi.class, false);
} catch (IllegalArgumentException e) {
return null;
}
while (readerSpiIter.hasNext()) {
ImageReaderSpi temp = (ImageReaderSpi) readerSpiIter.next();
if (temp.isOwnReader(reader)) {
readerSpi = temp;
break;
}
}
if (readerSpi == null) {
return null;
}
}
String[] writerNames = readerSpi.getImageWriterSpiNames();
if (writerNames == null) {
return null;
}
Class writerSpiClass = null;
try {
writerSpiClass = Class.forName(writerNames[0], true, ClassLoader.getSystemClassLoader());
} catch (ClassNotFoundException e) {
return null;
}
ImageWriterSpi writerSpi = (ImageWriterSpi) theRegistry.getServiceProviderByClass(writerSpiClass);
if (writerSpi == null) {
return null;
}
try {
return writerSpi.createWriterInstance();
} catch (IOException e) {
// Deregister the spi in this case, but only as a writerSpi
theRegistry.deregisterServiceProvider(writerSpi, ImageWriterSpi.class);
return null;
}
}
/**
* Returns an <code>ImageReader</code>corresponding to the given <code>ImageWriter</code>, if there is
* one, or <code>null</code> if the plug-in for this <code>ImageWriter</code> does not specify a
* corresponding <code>ImageReader</code>, or if the given <code>ImageWriter</code> is not registered.
* This method is provided principally for symmetry with <code>getImageWriter(ImageReader)</code>. Note
* that this method returns the "preferred" reader, which is the first in the list returned by
* javax.imageio.spi.ImageWriterSpi.<code>getImageReaderSpiNames()</code>.
*
* @param writer
* an instance of a registered <code>ImageWriter</code>.
*
* @return an <code>ImageReader</code>, or null.
*
* @exception IllegalArgumentException
* if <code>writer</code> is <code>null</code>.
*
* @see #getImageWriter(ImageReader)
* @see javax.imageio.spi.ImageWriterSpi#getImageReaderSpiNames()
*/
public static ImageReader getImageReader(ImageWriter writer) {
if (writer == null) {
throw new IllegalArgumentException("writer == null!");
}
ImageWriterSpi writerSpi = writer.getOriginatingProvider();
if (writerSpi == null) {
Iterator writerSpiIter;
// Ensure category is present
try {
writerSpiIter = theRegistry.getServiceProviders(ImageWriterSpi.class, false);
} catch (IllegalArgumentException e) {
return null;
}
while (writerSpiIter.hasNext()) {
ImageWriterSpi temp = (ImageWriterSpi) writerSpiIter.next();
if (temp.isOwnWriter(writer)) {
writerSpi = temp;
break;
}
}
if (writerSpi == null) {
return null;
}
}
String[] readerNames = writerSpi.getImageReaderSpiNames();
if (readerNames == null) {
return null;
}
Class readerSpiClass = null;
try {
readerSpiClass = Class.forName(readerNames[0], true, ClassLoader.getSystemClassLoader());
} catch (ClassNotFoundException e) {
return null;
}
ImageReaderSpi readerSpi = (ImageReaderSpi) theRegistry.getServiceProviderByClass(readerSpiClass);
if (readerSpi == null) {
return null;
}
try {
return readerSpi.createReaderInstance();
} catch (IOException e) {
// Deregister the spi in this case, but only as a readerSpi
theRegistry.deregisterServiceProvider(readerSpi, ImageReaderSpi.class);
return null;
}
}
/**
* Returns an <code>Iterator</code> containing all currently registered <code>ImageWriter</code>s that
* claim to be able to encode images of the given layout (specified using an
* <code>ImageTypeSpecifier</code>) in the given format.
*
* @param type
* an <code>ImageTypeSpecifier</code> indicating the layout of the image to be written.
* @param formatName
* the informal name of the <code>format</code>.
*
* @return an <code>Iterator</code> containing <code>ImageWriter</code>s.
*
* @exception IllegalArgumentException
* if any parameter is <code>null</code>.
*
* @see javax.imageio.spi.ImageWriterSpi#canEncodeImage(ImageTypeSpecifier)
*/
public static Iterator<ImageWriter> getImageWriters(ImageTypeSpecifier type, String formatName) {
if (type == null) {
throw new IllegalArgumentException("type == null!");
}
if (formatName == null) {
throw new IllegalArgumentException("formatName == null!");
}
Iterator iter;
// Ensure category is present
try {
iter = theRegistry.getServiceProviders(ImageWriterSpi.class, new CanEncodeImageAndFormatFilter(type, formatName), true);
} catch (IllegalArgumentException e) {
return new HashSet().iterator();
}
return new ImageWriterIterator(iter);
}
static class ImageTranscoderIterator implements Iterator<ImageTranscoder> {
// Contains ImageTranscoderSpis
public Iterator iter;
public ImageTranscoderIterator(Iterator iter) {
this.iter = iter;
}
public boolean hasNext() {
return iter.hasNext();
}
public ImageTranscoder next() {
ImageTranscoderSpi spi = null;
spi = (ImageTranscoderSpi) iter.next();
return spi.createTranscoderInstance();
}
public void remove() {
throw new UnsupportedOperationException();
}
}
static class TranscoderFilter implements ServiceRegistry.Filter {
String readerSpiName;
String writerSpiName;
public TranscoderFilter(ImageReaderSpi readerSpi, ImageWriterSpi writerSpi) {
this.readerSpiName = readerSpi.getClass().getName();
this.writerSpiName = writerSpi.getClass().getName();
}
public boolean filter(Object elt) {
ImageTranscoderSpi spi = (ImageTranscoderSpi) elt;
String readerName = spi.getReaderServiceProviderName();
String writerName = spi.getWriterServiceProviderName();
return (readerName.equals(readerSpiName) && writerName.equals(writerSpiName));
}
}
/**
* Returns an <code>Iterator</code> containing all currently registered <code>ImageTranscoder</code>s that
* claim to be able to transcode between the metadata of the given <code>ImageReader</code> and
* <code>ImageWriter</code>.
*
* @param reader
* an <code>ImageReader</code>.
* @param writer
* an <code>ImageWriter</code>.
*
* @return an <code>Iterator</code> containing <code>ImageTranscoder</code>s.
*
* @exception IllegalArgumentException
* if <code>reader</code> or <code>writer</code> is <code>null</code>.
*/
public static Iterator<ImageTranscoder> getImageTranscoders(ImageReader reader, ImageWriter writer) {
if (reader == null) {
throw new IllegalArgumentException("reader == null!");
}
if (writer == null) {
throw new IllegalArgumentException("writer == null!");
}
ImageReaderSpi readerSpi = reader.getOriginatingProvider();
ImageWriterSpi writerSpi = writer.getOriginatingProvider();
ServiceRegistry.Filter filter = new TranscoderFilter(readerSpi, writerSpi);
Iterator iter;
// Ensure category is present
try {
iter = theRegistry.getServiceProviders(ImageTranscoderSpi.class, filter, true);
} catch (IllegalArgumentException e) {
return new HashSet().iterator();
}
return new ImageTranscoderIterator(iter);
}
// All-in-one methods
/**
* Returns a <code>BufferedImage</code> as the result of decoding a supplied <code>File</code> with an
* <code>ImageReader</code> chosen automatically from among those currently registered. The
* <code>File</code> is wrapped in an <code>ImageInputStream</code>. If no registered
* <code>ImageReader</code> claims to be able to read the resulting stream, <code>null</code> is returned.
*
* <p>
* The current cache settings from <code>getUseCache</code>and <code>getCacheDirectory</code> will be used
* to control caching in the <code>ImageInputStream</code> that is created.
*
* <p>
* Note that there is no <code>read</code> method that takes a filename as a <code>String</code>; use this
* method instead after creating a <code>File</code> from the filename.
*
* <p>
* This method does not attempt to locate <code>ImageReader</code>s that can read directly from a
* <code>File</code>; that may be accomplished using <code>IIORegistry</code> and
* <code>ImageReaderSpi</code>.
*
* @param input
* a <code>File</code> to read from.
*
* @return a <code>BufferedImage</code> containing the decoded contents of the input, or <code>null</code>
* .
*
* @exception IllegalArgumentException
* if <code>input</code> is <code>null</code>.
* @exception IOException
* if an error occurs during reading.
*/
public static BufferedImage read(File input) throws IOException {
if (input == null) {
throw new IllegalArgumentException("input == null!");
}
if (!input.canRead()) {
throw new IIOException("Can't read input file!");
}
ImageInputStream stream = createImageInputStream(input);
if (stream == null) {
throw new IIOException("Can't create an ImageInputStream!");
}
BufferedImage bi = read(stream);
if (bi == null) {
stream.close();
}
return bi;
}
/**
* Returns a <code>BufferedImage</code> as the result of decoding a supplied <code>InputStream</code> with
* an <code>ImageReader</code> chosen automatically from among those currently registered. The
* <code>InputStream</code> is wrapped in an <code>ImageInputStream</code>. If no registered
* <code>ImageReader</code> claims to be able to read the resulting stream, <code>null</code> is returned.
*
* <p>
* The current cache settings from <code>getUseCache</code>and <code>getCacheDirectory</code> will be used
* to control caching in the <code>ImageInputStream</code> that is created.
*
* <p>
* This method does not attempt to locate <code>ImageReader</code>s that can read directly from an
* <code>InputStream</code>; that may be accomplished using <code>IIORegistry</code> and
* <code>ImageReaderSpi</code>.
*
* <p>
* This method <em>does not</em> close the provided <code>InputStream</code> after the read operation has
* completed; it is the responsibility of the caller to close the stream, if desired.
*
* @param input
* an <code>InputStream</code> to read from.
*
* @return a <code>BufferedImage</code> containing the decoded contents of the input, or <code>null</code>
* .
*
* @exception IllegalArgumentException
* if <code>input</code> is <code>null</code>.
* @exception IOException
* if an error occurs during reading.
*/
public static BufferedImage read(InputStream input) throws IOException {
if (input == null) {
throw new IllegalArgumentException("input == null!");
}
ImageInputStream stream = createImageInputStream(input);
BufferedImage bi = read(stream);
if (bi == null) {
stream.close();
}
return bi;
}
/**
* Returns a <code>BufferedImage</code> as the result of decoding a supplied <code>URL</code> with an
* <code>ImageReader</code> chosen automatically from among those currently registered. An
* <code>InputStream</code> is obtained from the <code>URL</code>, which is wrapped in an
* <code>ImageInputStream</code>. If no registered <code>ImageReader</code> claims to be able to read the
* resulting stream, <code>null</code> is returned.
*
* <p>
* The current cache settings from <code>getUseCache</code>and <code>getCacheDirectory</code> will be used
* to control caching in the <code>ImageInputStream</code> that is created.
*
* <p>
* This method does not attempt to locate <code>ImageReader</code>s that can read directly from a
* <code>URL</code>; that may be accomplished using <code>IIORegistry</code> and
* <code>ImageReaderSpi</code>.
*
* @param input
* a <code>URL</code> to read from.
*
* @return a <code>BufferedImage</code> containing the decoded contents of the input, or <code>null</code>
* .
*
* @exception IllegalArgumentException
* if <code>input</code> is <code>null</code>.
* @exception IOException
* if an error occurs during reading.
*/
public static BufferedImage read(URL input) throws IOException {
if (input == null) {
throw new IllegalArgumentException("input == null!");
}
InputStream istream = null;
try {
istream = input.openStream();
} catch (IOException e) {
throw new IIOException("Can't get input stream from URL!", e);
}
ImageInputStream stream = createImageInputStream(istream);
BufferedImage bi;
try {
bi = read(stream);
if (bi == null) {
stream.close();
}
} finally {
istream.close();
}
return bi;
}
/**
* Returns a <code>BufferedImage</code> as the result of decoding a supplied <code>ImageInputStream</code>
* with an <code>ImageReader</code> chosen automatically from among those currently registered. If no
* registered <code>ImageReader</code> claims to be able to read the stream, <code>null</code> is
* returned.
*
* <p>
* Unlike most other methods in this class, this method <em>does</em> close the provided
* <code>ImageInputStream</code> after the read operation has completed, unless <code>null</code> is
* returned, in which case this method <em>does not</em> close the stream.
*
* @param stream
* an <code>ImageInputStream</code> to read from.
*
* @return a <code>BufferedImage</code> containing the decoded contents of the input, or <code>null</code>
* .
*
* @exception IllegalArgumentException
* if <code>stream</code> is <code>null</code>.
* @exception IOException
* if an error occurs during reading.
*/
public static BufferedImage read(ImageInputStream stream) throws IOException {
if (stream == null) {
throw new IllegalArgumentException("stream == null!");
}
BufferedImage bi = null;
Iterator iter = getImageReaders(stream);
IOException lastException = null;
while (iter.hasNext()) {
ImageReader reader = null;
try {
reader = (ImageReader) iter.next();
ImageReadParam param = reader.getDefaultReadParam();
reader.setInput(stream, true, true);
Iterator<ImageTypeSpecifier> imageTypes = reader.getImageTypes(0);
while (imageTypes.hasNext()) {
ImageTypeSpecifier imageTypeSpecifier = imageTypes.next();
int bufferedImageType = imageTypeSpecifier.getBufferedImageType();
if (bufferedImageType == BufferedImage.TYPE_BYTE_GRAY) {
param.setDestinationType(imageTypeSpecifier);
break;
}
}
bi = reader.read(0, param);
if (null != bi)
break;
} catch (IOException e) {
lastException = e;
} finally {
if (null != reader) {
reader.dispose();
stream.close();
}
}
}
// If you don't have an image at the end of all readers
if (null == bi) {
if (null != lastException) {
throw lastException;
}
}
return bi;
}
/**
* Writes an image using the an arbitrary <code>ImageWriter</code> that supports the given format to an
* <code>ImageOutputStream</code>. The image is written to the <code>ImageOutputStream</code> starting at
* the current stream pointer, overwriting existing stream data from that point forward, if present.
*
* <p>
* This method <em>does not</em> close the provided <code>ImageOutputStream</code> after the write
* operation has completed; it is the responsibility of the caller to close the stream, if desired.
*
* @param im
* a <code>RenderedImage</code> to be written.
* @param formatName
* a <code>String</code> containg the informal name of the format.
* @param output
* an <code>ImageOutputStream</code> to be written to.
*
* @return <code>false</code> if no appropriate writer is found.
*
* @exception IllegalArgumentException
* if any parameter is <code>null</code>.
* @exception IOException
* if an error occurs during writing.
*/
public static boolean write(RenderedImage im, String formatName, ImageOutputStream output) throws IOException {
if (im == null) {
throw new IllegalArgumentException("im == null!");
}
if (formatName == null) {
throw new IllegalArgumentException("formatName == null!");
}
if (output == null) {
throw new IllegalArgumentException("output == null!");
}
ImageWriter writer = null;
ImageTypeSpecifier type = ImageTypeSpecifier.createFromRenderedImage(im);
Iterator iter = getImageWriters(type, formatName);
if (iter.hasNext()) {
writer = (ImageWriter) iter.next();
}
if (writer == null) {
return false;
}
writer.setOutput(output);
try {
writer.write(im);
} finally {
writer.dispose();
output.flush();
}
return true;
}
/**
* Writes an image using an arbitrary <code>ImageWriter</code> that supports the given format to a
* <code>File</code>. If there is already a <code>File</code> present, its contents are discarded.
*
* @param im
* a <code>RenderedImage</code> to be written.
* @param formatName
* a <code>String</code> containg the informal name of the format.
* @param output
* a <code>File</code> to be written to.
*
* @return <code>false</code> if no appropriate writer is found.
*
* @exception IllegalArgumentException
* if any parameter is <code>null</code>.
* @exception IOException
* if an error occurs during writing.
*/
public static boolean write(RenderedImage im, String formatName, File output) throws IOException {
if (output == null) {
throw new IllegalArgumentException("output == null!");
}
ImageOutputStream stream = null;
try {
output.delete();
stream = createImageOutputStream(output);
} catch (IOException e) {
throw new IIOException("Can't create output stream!", e);
}
boolean val;
try {
val = write(im, formatName, stream);
} finally {
stream.close();
}
return val;
}
/**
* Writes an image using an arbitrary <code>ImageWriter</code> that supports the given format to an
* <code>OutputStream</code>.
*
* <p>
* This method <em>does not</em> close the provided <code>OutputStream</code> after the write operation
* has completed; it is the responsibility of the caller to close the stream, if desired.
*
* <p>
* The current cache settings from <code>getUseCache</code>and <code>getCacheDirectory</code> will be used
* to control caching.
*
* @param im
* a <code>RenderedImage</code> to be written.
* @param formatName
* a <code>String</code> containg the informal name of the format.
* @param output
* an <code>OutputStream</code> to be written to.
*
* @return <code>false</code> if no appropriate writer is found.
*
* @exception IllegalArgumentException
* if any parameter is <code>null</code>.
* @exception IOException
* if an error occurs during writing.
*/
public static boolean write(RenderedImage im, String formatName, OutputStream output) throws IOException {
if (output == null) {
throw new IllegalArgumentException("output == null!");
}
ImageOutputStream stream = null;
try {
stream = createImageOutputStream(output);
} catch (IOException e) {
throw new IIOException("Can't create output stream!", e);
}
boolean val;
try {
val = write(im, formatName, stream);
} finally {
stream.close();
}
return val;
}
}
