1/* 2 * Copyright (c) 1999, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26package javax.imageio.spi; 27 28import java.security.PrivilegedAction; 29import java.security.AccessController; 30import java.util.HashMap; 31import java.util.Iterator; 32import java.util.Map; 33import java.util.NoSuchElementException; 34import java.util.Set; 35import java.util.Vector; 36import com.sun.imageio.spi.FileImageInputStreamSpi; 37import com.sun.imageio.spi.FileImageOutputStreamSpi; 38import com.sun.imageio.spi.InputStreamImageInputStreamSpi; 39import com.sun.imageio.spi.OutputStreamImageOutputStreamSpi; 40import com.sun.imageio.spi.RAFImageInputStreamSpi; 41import com.sun.imageio.spi.RAFImageOutputStreamSpi; 42import com.sun.imageio.plugins.gif.GIFImageReaderSpi; 43import com.sun.imageio.plugins.gif.GIFImageWriterSpi; 44import com.sun.imageio.plugins.jpeg.JPEGImageReaderSpi; 45import com.sun.imageio.plugins.jpeg.JPEGImageWriterSpi; 46import com.sun.imageio.plugins.png.PNGImageReaderSpi; 47import com.sun.imageio.plugins.png.PNGImageWriterSpi; 48import com.sun.imageio.plugins.bmp.BMPImageReaderSpi; 49import com.sun.imageio.plugins.bmp.BMPImageWriterSpi; 50import com.sun.imageio.plugins.wbmp.WBMPImageReaderSpi; 51import com.sun.imageio.plugins.wbmp.WBMPImageWriterSpi; 52import com.sun.imageio.plugins.tiff.TIFFImageReaderSpi; 53import com.sun.imageio.plugins.tiff.TIFFImageWriterSpi; 54import sun.awt.AppContext; 55import java.util.ServiceLoader; 56import java.util.ServiceConfigurationError; 57 58/** 59 * A registry for service provider instances. Service provider 60 * classes may be detected at run time by means of meta-information in 61 * the JAR files containing them. The intent is that it be relatively 62 * inexpensive to load and inspect all available service provider 63 * classes. These classes may them be used to locate and instantiate 64 * more heavyweight classes that will perform actual work, in this 65 * case instances of {@code ImageReader}, 66 * {@code ImageWriter}, {@code ImageTranscoder}, 67 * {@code ImageInputStream}, and {@code ImageOutputStream}. 68 * 69 * Service providers found from the Java platform are automatically 70 * loaded as soon as this class is instantiated. 71 * 72 * <p> When the {@code registerApplicationClasspathSpis} method 73 * is called, service provider instances declared in the 74 * meta-information section of JAR files on the application class path 75 * are loaded. To declare a service provider, a {@code services} 76 * subdirectory is placed within the {@code META-INF} directory 77 * that is present in every JAR file. This directory contains a file 78 * for each service provider interface that has one or more 79 * implementation classes present in the JAR file. For example, if 80 * the JAR file contained a class named 81 * {@code com.mycompany.imageio.MyFormatReaderSpi} which 82 * implements the {@code ImageReaderSpi} interface, the JAR file 83 * would contain a file named: 84 * 85 * <pre> 86 * META-INF/services/javax.imageio.spi.ImageReaderSpi 87 * </pre> 88 * 89 * containing the line: 90 * 91 * <pre> 92 * com.mycompany.imageio.MyFormatReaderSpi 93 * </pre> 94 * 95 * <p> The service provider classes are intended to be lightweight 96 * and quick to load. Implementations of these interfaces 97 * should avoid complex dependencies on other classes and on 98 * native code. 99 * 100 * <p> It is also possible to manually add service providers not found 101 * automatically, as well as to remove those that are using the 102 * interfaces of the {@code ServiceRegistry} class. Thus 103 * the application may customize the contents of the registry as it 104 * sees fit. 105 * 106 * <p> For more details on declaring service providers, and the JAR 107 * format in general, see the 108 * <a href="{@docRoot}/../specs/jar/jar.html">JAR File Specification</a>. 109 */ 110public final class IIORegistry extends ServiceRegistry { 111 112 /** 113 * A {@code Vector} containing the valid IIO registry 114 * categories (superinterfaces) to be used in the constructor. 115 */ 116 private static final Vector<Class<?>> initialCategories = new Vector<>(5); 117 118 static { 119 initialCategories.add(ImageReaderSpi.class); 120 initialCategories.add(ImageWriterSpi.class); 121 initialCategories.add(ImageTranscoderSpi.class); 122 initialCategories.add(ImageInputStreamSpi.class); 123 initialCategories.add(ImageOutputStreamSpi.class); 124 } 125 126 /** 127 * Set up the valid service provider categories and automatically 128 * register all available service providers. 129 * 130 * <p> The constructor is private in order to prevent creation of 131 * additional instances. 132 */ 133 private IIORegistry() { 134 super(initialCategories.iterator()); 135 registerStandardSpis(); 136 registerApplicationClasspathSpis(); 137 } 138 139 /** 140 * Returns the default {@code IIORegistry} instance used by 141 * the Image I/O API. This instance should be used for all 142 * registry functions. 143 * 144 * <p> Each {@code ThreadGroup} will receive its own 145 * instance; this allows different {@code Applet}s in the 146 * same browser (for example) to each have their own registry. 147 * 148 * @return the default registry for the current 149 * {@code ThreadGroup}. 150 */ 151 public static IIORegistry getDefaultInstance() { 152 AppContext context = AppContext.getAppContext(); 153 IIORegistry registry = 154 (IIORegistry)context.get(IIORegistry.class); 155 if (registry == null) { 156 // Create an instance for this AppContext 157 registry = new IIORegistry(); 158 context.put(IIORegistry.class, registry); 159 } 160 return registry; 161 } 162 163 private void registerStandardSpis() { 164 // Hardwire standard SPIs 165 registerServiceProvider(new GIFImageReaderSpi()); 166 registerServiceProvider(new GIFImageWriterSpi()); 167 registerServiceProvider(new BMPImageReaderSpi()); 168 registerServiceProvider(new BMPImageWriterSpi()); 169 registerServiceProvider(new WBMPImageReaderSpi()); 170 registerServiceProvider(new WBMPImageWriterSpi()); 171 registerServiceProvider(new TIFFImageReaderSpi()); 172 registerServiceProvider(new TIFFImageWriterSpi()); 173 registerServiceProvider(new PNGImageReaderSpi()); 174 registerServiceProvider(new PNGImageWriterSpi()); 175 registerServiceProvider(new JPEGImageReaderSpi()); 176 registerServiceProvider(new JPEGImageWriterSpi()); 177 registerServiceProvider(new FileImageInputStreamSpi()); 178 registerServiceProvider(new FileImageOutputStreamSpi()); 179 registerServiceProvider(new InputStreamImageInputStreamSpi()); 180 registerServiceProvider(new OutputStreamImageOutputStreamSpi()); 181 registerServiceProvider(new RAFImageInputStreamSpi()); 182 registerServiceProvider(new RAFImageOutputStreamSpi()); 183 184 registerInstalledProviders(); 185 } 186 187 /** 188 * Registers all available service providers found on the 189 * application class path, using the default 190 * {@code ClassLoader}. This method is typically invoked by 191 * the {@code ImageIO.scanForPlugins} method. 192 * 193 * @see javax.imageio.ImageIO#scanForPlugins 194 * @see ClassLoader#getResources 195 */ 196 public void registerApplicationClasspathSpis() { 197 // FIX: load only from application classpath 198 199 ClassLoader loader = Thread.currentThread().getContextClassLoader(); 200 201 Iterator<Class<?>> categories = getCategories(); 202 while (categories.hasNext()) { 203 @SuppressWarnings("unchecked") 204 Class<IIOServiceProvider> c = (Class<IIOServiceProvider>)categories.next(); 205 Iterator<IIOServiceProvider> riter = 206 ServiceLoader.load(c, loader).iterator(); 207 while (riter.hasNext()) { 208 try { 209 // Note that the next() call is required to be inside 210 // the try/catch block; see 6342404. 211 IIOServiceProvider r = riter.next(); 212 registerServiceProvider(r); 213 } catch (ServiceConfigurationError err) { 214 if (System.getSecurityManager() != null) { 215 // In the applet case, we will catch the error so 216 // registration of other plugins can proceed 217 err.printStackTrace(); 218 } else { 219 // In the application case, we will throw the 220 // error to indicate app/system misconfiguration 221 throw err; 222 } 223 } 224 } 225 } 226 } 227 228 private void registerInstalledProviders() { 229 /* 230 We need to load installed providers 231 in the privileged mode in order to 232 be able read corresponding jar files even if 233 file read capability is restricted (like the 234 applet context case). 235 */ 236 PrivilegedAction<Object> doRegistration = 237 new PrivilegedAction<Object>() { 238 public Object run() { 239 Iterator<Class<?>> categories = getCategories(); 240 while (categories.hasNext()) { 241 @SuppressWarnings("unchecked") 242 Class<IIOServiceProvider> c = (Class<IIOServiceProvider>)categories.next(); 243 for (IIOServiceProvider p : ServiceLoader.loadInstalled(c)) { 244 registerServiceProvider(p); 245 } 246 } 247 return this; 248 } 249 }; 250 251 AccessController.doPrivileged(doRegistration); 252 } 253} 254