Java tutorial
/** * Copyright 2011 The ForPlay Authors * * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except * in compliance with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software distributed under the License * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express * or implied. See the License for the specific language governing permissions and limitations under * the License. */ package forplay.rebind; import java.io.File; import java.io.FileFilter; import java.io.IOException; import java.io.PrintWriter; import java.util.HashSet; import java.util.Map; import java.util.Set; import com.google.gwt.core.client.GWT; import com.google.gwt.core.ext.Generator; import com.google.gwt.core.ext.GeneratorContext; import com.google.gwt.core.ext.TreeLogger; import com.google.gwt.core.ext.UnableToCompleteException; import com.google.gwt.core.ext.typeinfo.JClassType; import com.google.gwt.core.ext.typeinfo.NotFoundException; import com.google.gwt.core.ext.typeinfo.TypeOracle; import com.google.gwt.dev.util.collect.HashMap; import com.google.gwt.resources.client.ClientBundleWithLookup; import com.google.gwt.resources.client.DataResource; import com.google.gwt.resources.client.ImageResource; import com.google.gwt.resources.client.ResourcePrototype; import com.google.gwt.resources.client.TextResource; import com.google.gwt.user.rebind.ClassSourceFileComposerFactory; import com.google.gwt.user.rebind.SourceWriter; import forplay.core.Asserts; /** * Automatically generate a client bundle from the resources available in the provided interface's * package directory and below. */ public class AutoClientBundleGenerator extends Generator { private static final Map<String, String> EXTENSION_MAP = new HashMap<String, String>(); private static FileFilter fileFilter = new FileFilter() { @Override public boolean accept(File file) { if (file.isDirectory()) { // Skip .svn directories if (file.getName().equals(".svn")) { return false; } // By default descend into all directories return true; } else { // Include only all explicitly mapped extensions String extension = getExtension(file.getName()); return EXTENSION_MAP.containsKey(extension); } } }; private static final String WEB_INF_CLASSES = "WEB-INF/classes/"; static { EXTENSION_MAP.put(".png", "image/png"); EXTENSION_MAP.put(".gif", "image/gif"); EXTENSION_MAP.put(".jpg", "image/jpeg"); /* * Do not include WAV files, since HTML5 audio playback ended events are not yet a part of GWT * 2.2.0, which means we won't know when these sounds stop playing. * * EXTENSION_MAP.put(".wav", "audio/wav"); */ EXTENSION_MAP.put(".mp3", "audio/mp3"); EXTENSION_MAP.put(".json", "text/json"); } private static String getContentType(TreeLogger logger, File file) { String name = file.getName().toLowerCase(); int pos = name.lastIndexOf('.'); String extension = pos == -1 ? "" : name.substring(pos); String contentType = EXTENSION_MAP.get(extension); if (contentType == null) { logger.log(TreeLogger.WARN, "No Content Type mapping for files with '" + extension + "' extension. Please add a mapping to the " + AutoClientBundleGenerator.class.getCanonicalName() + " class."); contentType = "application/octet-stream"; } return contentType; } /** * Determine whether the provided method name is valid in Java. */ private static boolean isValidMethodName(String methodName) { return methodName.matches("^[a-zA-Z_$][a-zA-Z0-9_$]*$"); // TODO: fix regex } /** * Strip off the filename extension, if it's present. */ private static String stripExtension(String filename) { return filename.replaceFirst("\\.[^.]+$", ""); } /** * Get the filename extension or return an empty string if there's no extension. */ private static String getExtension(String filename) { return filename.replaceFirst(".*(\\.[^.]+)$", "$1"); } @Override public String generate(TreeLogger logger, GeneratorContext context, String typeName) throws UnableToCompleteException { TypeOracle typeOracle = context.getTypeOracle(); JClassType userType; try { userType = typeOracle.getType(typeName); } catch (NotFoundException e) { logger.log(TreeLogger.ERROR, "Unable to find metadata for type: " + typeName, e); throw new UnableToCompleteException(); } String packageName = userType.getPackage().getName(); String className = userType.getName(); className = className.replace('.', '_'); if (userType.isInterface() == null) { logger.log(TreeLogger.ERROR, userType.getQualifiedSourceName() + " is not an interface", null); throw new UnableToCompleteException(); } ClassSourceFileComposerFactory composerFactory = new ClassSourceFileComposerFactory(packageName, className + "Impl"); composerFactory.addImplementedInterface(userType.getQualifiedSourceName()); composerFactory.addImport(ClientBundleWithLookup.class.getName()); composerFactory.addImport(DataResource.class.getName()); composerFactory.addImport(GWT.class.getName()); composerFactory.addImport(ImageResource.class.getName()); composerFactory.addImport(ResourcePrototype.class.getName()); composerFactory.addImport(TextResource.class.getName()); File warDirectory = getWarDirectory(logger); Asserts.check(warDirectory.isDirectory()); File classesDirectory = new File(warDirectory, WEB_INF_CLASSES); Asserts.check(classesDirectory.isDirectory()); File resourcesDirectory = new File(classesDirectory, packageName.replace('.', '/')); Asserts.check(resourcesDirectory.isDirectory()); String baseClassesPath = classesDirectory.getPath(); logger.log(TreeLogger.DEBUG, "baseClassesPath: " + baseClassesPath); Set<File> files = preferMp3(getFiles(resourcesDirectory, fileFilter)); Set<String> methodNames = new HashSet<String>(); PrintWriter pw = context.tryCreate(logger, packageName, className + "Impl"); if (pw != null) { SourceWriter sw = composerFactory.createSourceWriter(context, pw); // write out jump methods sw.println("public ResourcePrototype[] getResources() {"); sw.indent(); sw.println("return MyBundle.INSTANCE.getResources();"); sw.outdent(); sw.println("}"); sw.println("public ResourcePrototype getResource(String name) {"); sw.indent(); sw.println("return MyBundle.INSTANCE.getResource(name);"); sw.outdent(); sw.println("}"); // write out static ClientBundle interface sw.println("static interface MyBundle extends ClientBundleWithLookup {"); sw.indent(); sw.println("MyBundle INSTANCE = GWT.create(MyBundle.class);"); for (File file : files) { String filepath = file.getPath(); String relativePath = filepath.replace(baseClassesPath, "").replace('\\', '/').replaceFirst("^/", ""); String filename = file.getName(); String contentType = getContentType(logger, file); String methodName = stripExtension(filename); if (!isValidMethodName(methodName)) { logger.log(TreeLogger.WARN, "Skipping invalid method name (" + methodName + ") due to: " + relativePath); continue; } if (!methodNames.add(methodName)) { logger.log(TreeLogger.WARN, "Skipping duplicate method name due to: " + relativePath); continue; } logger.log(TreeLogger.DEBUG, "Generating method for: " + relativePath); Class<? extends ResourcePrototype> returnType = getResourcePrototype(contentType); // generate method sw.println(); if (returnType == DataResource.class) { if (contentType.startsWith("audio/")) { // Prevent the use of data URLs, which Flash won't play sw.println("@DataResource.DoNotEmbed"); } else { // Specify an explicit MIME type, for use in the data URL sw.println("@DataResource.MimeType(\"" + contentType + "\")"); } } sw.println("@Source(\"" + relativePath + "\")"); sw.println(returnType.getName() + " " + methodName + "();"); } sw.outdent(); sw.println("}"); sw.commit(logger); } return composerFactory.getCreatedClassName(); } /** * Filter file set, preferring *.mp3 files where alternatives exist. */ private HashSet<File> preferMp3(Set<File> files) { HashMap<String, File> map = new HashMap<String, File>(); for (File file : files) { String path = stripExtension(file.getPath()); if (file.getName().endsWith(".mp3") || !map.containsKey(path)) { map.put(path, file); } } return new HashSet<File>(map.values()); } /** * Recursively get a list of files in the provided directory. */ private HashSet<File> getFiles(File dir, FileFilter filter) { Asserts.checkNotNull(dir); Asserts.checkNotNull(filter); Asserts.checkArgument(dir.isDirectory()); HashSet<File> fileList = new HashSet<File>(); File[] files = dir.listFiles(filter); for (int i = 0; i < files.length; i++) { File f = files[i]; if (f.isFile()) { // f = file fileList.add(f); } else { // f = directory if (filter.accept(f)) { fileList.addAll(getFiles(f, filter)); } } } return fileList; } private Class<? extends ResourcePrototype> getResourcePrototype(String contentType) { Class<? extends ResourcePrototype> returnType; if (contentType.startsWith("image/")) { returnType = ImageResource.class; } else if (contentType.startsWith("text/")) { returnType = TextResource.class; } else { returnType = DataResource.class; } return returnType; } /** * When invoking the GWT compiler from GPE, the working directory is the Eclipse project * directory. However, when launching a GPE project, the working directory is the project 'war' * directory. This methods returns the war directory in either case in a fairly naive and * non-robust manner. */ private File getWarDirectory(TreeLogger logger) throws UnableToCompleteException { File currentDirectory = new File("."); try { String canonicalPath = currentDirectory.getCanonicalPath(); logger.log(TreeLogger.INFO, "Current directory in which this generator is executing: " + canonicalPath); if (canonicalPath.endsWith("war")) { return currentDirectory; } else { return new File("war"); } } catch (IOException e) { logger.log(TreeLogger.ERROR, "Failed to get canonical path", e); throw new UnableToCompleteException(); } } }