Java tutorial
/* * Copyright 2013 Red Hat Inc. and/or its affiliates and other contributors. * * 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 org.switchyard.console.components.rebind; import java.io.PrintWriter; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import org.switchyard.console.components.client.extension.ComponentExtension; import org.switchyard.console.components.client.extension.ComponentProvider; import org.switchyard.console.components.client.internal.ComponentExtensionManager; import org.switchyard.console.components.client.internal.ComponentProviderProxyImpl; 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.TypeOracle; import com.google.gwt.user.rebind.ClassSourceFileComposerFactory; import com.google.gwt.user.rebind.SourceWriter; import com.google.inject.Inject; /** * ComponentExtensionManagerGenerator * * GWT code generator for ComponentExtensionManager. A code generator is used * because reflection cannot be used on the client side. This generator scans * for classes annotated with ComponentExtension and adds them to the manager. * * @author Rob Cernich */ public class ComponentExtensionManagerGenerator extends Generator { @Override public String generate(TreeLogger logger, GeneratorContext context, String typeName) throws UnableToCompleteException { TypeOracle typeOracle = context.getTypeOracle(); JClassType componentExtensionManager = typeOracle.findType(typeName); if (componentExtensionManager == null) { logger.log(TreeLogger.ERROR, "Unable to find metadata for type '" + typeName + "'", null); throw new UnableToCompleteException(); } if (componentExtensionManager.isInterface() == null) { logger.log(TreeLogger.ERROR, componentExtensionManager.getQualifiedSourceName() + " is not an interface", null); throw new UnableToCompleteException(); } JClassType componentProvider = typeOracle.findType(ComponentProvider.class.getCanonicalName()); if (componentProvider == null) { logger.log(TreeLogger.ERROR, "Unable to find metadata for type 'ComponentProvider'", null); throw new UnableToCompleteException(); } List<JClassType> componentExtensionClasses = new ArrayList<JClassType>(); for (JClassType type : typeOracle.getTypes()) { if (type.isAnnotationPresent(ComponentExtension.class)) { if (type.isClass() == null || type.isAbstract()) { // type must be a class that can be instantiated logger.log(TreeLogger.ERROR, "ComponentExtension type '" + type.getQualifiedSourceName() + "' cannot be instantiated.", null); throw new UnableToCompleteException(); } else if (!type.isDefaultInstantiable()) { // type must have default constructor logger.log(TreeLogger.ERROR, "ComponentExtension type '" + type.getQualifiedSourceName() + "' does not provide a default constructor.", null); throw new UnableToCompleteException(); } else if (!type.isAssignableTo(componentProvider)) { // type must implement ComponentProvider logger.log(TreeLogger.ERROR, "ComponentExtension type '" + type.getQualifiedSourceName() + "' does not implement ComponentProvider.", null); throw new UnableToCompleteException(); } componentExtensionClasses.add(type); } } String packageName = componentExtensionManager.getPackage().getName(); String className = componentExtensionManager.getSimpleSourceName() + "Impl"; generateClass(logger, context, packageName, className, componentExtensionClasses); return packageName + "." + className; } private void generateClass(TreeLogger logger, GeneratorContext context, String packageName, String className, List<JClassType> componentExtensionClasses) { PrintWriter pw = context.tryCreate(logger, packageName, className); if (pw == null) { return; } ClassSourceFileComposerFactory composerFactory = new ClassSourceFileComposerFactory(packageName, className); // imports composerFactory.addImport(HashMap.class.getCanonicalName()); composerFactory.addImport(Map.class.getCanonicalName()); composerFactory.addImport(ComponentProvider.class.getCanonicalName()); composerFactory.addImport(ComponentExtensionManager.class.getCanonicalName()); composerFactory.addImport(ComponentProviderProxyImpl.class.getCanonicalName()); composerFactory.addImport(GWT.class.getCanonicalName()); composerFactory.addImport(Inject.class.getCanonicalName()); // interface composerFactory.addImplementedInterface(ComponentExtensionManager.class.getCanonicalName()); SourceWriter sw = composerFactory.createSourceWriter(context, pw); // fields sw.println( "private Map<String, ComponentProviderProxy> _providers = new HashMap<String, ComponentProviderProxy>();"); sw.println("private Map<String, String> _typeToName = new HashMap<String, String>();"); // constructor sw.println("public " + className + "() {"); sw.indent(); for (JClassType extensionClass : componentExtensionClasses) { ComponentExtension extensionAnnotation = extensionClass.getAnnotation(ComponentExtension.class); sw.println("_providers.put(\"" + extensionAnnotation.componentName() + "\", new ComponentProviderProxyImpl(\"" + extensionAnnotation.displayName() + "\") {"); sw.indent(); sw.println("public ComponentProvider instantiate() {"); sw.indentln("return GWT.create(" + extensionClass.getQualifiedSourceName() + ".class);"); sw.println("}"); sw.outdent(); sw.println("});"); for (String type : extensionAnnotation.activationTypes()) { sw.println("_typeToName.put(\"" + type + "\", \"" + extensionAnnotation.componentName() + "\");"); } } sw.outdent(); sw.println("}"); // methods // getExtensionProviders sw.println("public Map<String, ComponentProviderProxy> getExtensionProviders() {"); sw.indentln("return _providers;"); sw.println("}"); // getExtensionProviderByComponentName sw.println("public ComponentProviderProxy getExtensionProviderByComponentName(String componentName) {"); sw.indent(); sw.println("if (_providers.containsKey(componentName)) {"); sw.indentln("return _providers.get(componentName);"); sw.println("}"); sw.println("return null;"); sw.outdent(); sw.println("}"); // getExtensionProviderByTypeName sw.println("public ComponentProviderProxy getExtensionProviderByTypeName(String typeName) {"); sw.indent(); sw.println("if (_typeToName.containsKey(typeName)) {"); sw.indentln("return getExtensionProviderByComponentName(_typeToName.get(typeName));"); sw.println("}"); sw.println("return null;"); sw.outdent(); sw.println("}"); // close it out sw.outdent(); sw.println("}"); context.commit(logger, pw); } }