Java tutorial
package org.bimserver.shared.reflector; /****************************************************************************** * Copyright (C) 2009-2013 BIMserver.org * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as * published by the Free Software Foundation, either version 3 of the * License, or (at your option) any later version. * * This program 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 Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. *****************************************************************************/ import java.io.File; import java.io.IOException; import javassist.CannotCompileException; import javassist.ClassClassPath; import javassist.ClassPool; import javassist.CtClass; import javassist.CtConstructor; import javassist.CtField; import javassist.CtMethod; import javassist.NotFoundException; import org.apache.commons.io.FileUtils; import org.bimserver.shared.interfaces.PublicInterface; import org.bimserver.shared.meta.SMethod; import org.bimserver.shared.meta.SParameter; import org.bimserver.shared.meta.SService; import org.bimserver.shared.meta.SServicesMap; import org.slf4j.Logger; import org.slf4j.LoggerFactory; public class RealtimeReflectorFactoryBuilder implements ReflectorFactoryBuilder { private static final Logger LOGGER = LoggerFactory.getLogger(RealtimeReflectorFactoryBuilder.class); private SServicesMap servicesMap; private ClassPool pool; private static int implementationCounter = 0; private static final String GENERATED_CLASSES_PACKAGE = "org.bimserver.generated"; private File generatedClassesDir; public RealtimeReflectorFactoryBuilder(SServicesMap servicesMap) { this.servicesMap = servicesMap; } public RealtimeReflectorFactoryBuilder(SServicesMap servicesMap, File generatedClassesDir) { this.servicesMap = servicesMap; this.generatedClassesDir = generatedClassesDir; } public ReflectorFactory newReflectorFactory() { implementationCounter++; try { pool = ClassPool.getDefault(); pool.insertClassPath(new ClassClassPath(this.getClass())); for (String name : servicesMap.keySetName()) { SService sService = servicesMap.getByName(name); build1((Class<? extends PublicInterface>) sService.getInterfaceClass(), sService); build2((Class<? extends PublicInterface>) sService.getInterfaceClass(), sService); } CtClass reflectorFactoryImpl = pool .makeClass("org.bimserver.reflector.ReflectorFactoryImpl" + implementationCounter); reflectorFactoryImpl.addInterface(pool.get(ReflectorFactory.class.getName())); createCreateReflectorMethod1(reflectorFactoryImpl); createCreateReflectorMethod2(reflectorFactoryImpl); writeClassFile(reflectorFactoryImpl); Class<?> class1 = pool.toClass(reflectorFactoryImpl, getClass().getClassLoader(), getClass().getProtectionDomain()); return (ReflectorFactory) class1.newInstance(); } catch (Exception e) { LOGGER.error("", e); } return null; } private void writeClassFile(CtClass ctClass) throws IOException, CannotCompileException { if (generatedClassesDir != null) { File dir = new File(generatedClassesDir, ctClass.getPackageName().replace(".", "/")); FileUtils.forceMkdir(dir); FileUtils.writeByteArrayToFile(new File(dir, ctClass.getSimpleName() + ".class"), ctClass.toBytecode()); } } private void createCreateReflectorMethod2(CtClass reflectorFactoryImpl) throws NotFoundException, CannotCompileException { CtClass[] parameters = new CtClass[2]; parameters[0] = pool.get(Class.class.getName()); parameters[1] = pool.get(PublicInterface.class.getName()); CtMethod method = new CtMethod(pool.get(Reflector.class.getName()), "createReflector", parameters, reflectorFactoryImpl); StringBuilder methodBuilder = new StringBuilder(); methodBuilder.append("{"); methodBuilder.append("if (1==0) {"); for (String name : servicesMap.keySetName()) { SService sService = servicesMap.getByName(name); methodBuilder.append("} else if ($1.getSimpleName().equals(\"" + sService.getSimpleName() + "\")) {"); methodBuilder .append("return new " + GENERATED_CLASSES_PACKAGE + "." + sService.getSimpleName() + "Reflector" + implementationCounter + "((" + sService.getInterfaceClass().getName() + ")$2);"); } methodBuilder.append("}"); methodBuilder.append("return null;"); methodBuilder.append("}"); method.setBody(methodBuilder.toString()); reflectorFactoryImpl.addMethod(method); } private void createCreateReflectorMethod1(CtClass reflectorFactoryImpl) throws NotFoundException, CannotCompileException { CtClass[] parameters = new CtClass[2]; parameters[0] = pool.get(Class.class.getName()); parameters[1] = pool.get(Reflector.class.getName()); CtMethod method = new CtMethod(pool.get(PublicInterface.class.getName()), "createReflector", parameters, reflectorFactoryImpl); StringBuilder methodBuilder = new StringBuilder(); methodBuilder.append("{"); methodBuilder.append("if (1==0) {"); for (String name : servicesMap.keySetName()) { SService sService = servicesMap.getByName(name); methodBuilder.append("} else if ($1.getSimpleName().equals(\"" + sService.getSimpleName() + "\")) {"); methodBuilder.append("return new " + GENERATED_CLASSES_PACKAGE + "." + sService.getSimpleName() + "Impl" + implementationCounter + "($2);"); } methodBuilder.append("}"); methodBuilder.append("return null;"); methodBuilder.append("}"); method.setBody(methodBuilder.toString()); reflectorFactoryImpl.addMethod(method); } private void build1(Class<? extends PublicInterface> interfaceClass, org.bimserver.shared.meta.SService sService) { try { CtClass reflectorImplClass = pool.makeClass(GENERATED_CLASSES_PACKAGE + "." + interfaceClass.getSimpleName() + "Impl" + implementationCounter); reflectorImplClass.addInterface(pool.get(interfaceClass.getName())); CtClass reflectorClass = pool.get(Reflector.class.getName()); CtField reflectorField = new CtField(reflectorClass, "reflector", reflectorImplClass); reflectorImplClass.addField(reflectorField); CtConstructor constructor = new CtConstructor(new CtClass[] { reflectorClass }, reflectorImplClass); StringBuilder sb = new StringBuilder(); reflectorImplClass.addConstructor(constructor); sb.append("{"); sb.append("this.reflector = $1;"); sb.append("}"); constructor.setBody(sb.toString()); for (SMethod sMethod : sService.getMethods()) { CtClass[] parameters = new CtClass[sMethod.getParameters().size()]; int i = 0; for (org.bimserver.shared.meta.SParameter sParameter : sMethod.getParameters()) { parameters[i] = pool.get(sParameter.getType().toJavaCode()); i++; } CtMethod method = new CtMethod(pool.get(sMethod.getReturnType().toJavaCode()), sMethod.getName(), parameters, reflectorImplClass); StringBuilder methodBuilder = new StringBuilder(); methodBuilder.append("{"); if (sMethod.getReturnType().isVoid()) { } else { methodBuilder.append("return (" + sMethod.getReturnType().toJavaCode() + ")"); } methodBuilder.append("reflector.callMethod(\"" + interfaceClass.getSimpleName() + "\", \"" + sMethod.getName() + "\", " + sMethod.getReturnType().toJavaCode() + ".class"); if (sMethod.getParameters().isEmpty()) { methodBuilder.append(", new " + KeyValuePair.class.getName() + "[0]"); } else { methodBuilder.append(", new " + KeyValuePair.class.getName() + "[]{"); int x = 1; for (SParameter sParameter : sMethod.getParameters()) { methodBuilder.append("new " + KeyValuePair.class.getName() + "(\"" + sParameter.getName() + "\", $" + x + ")"); if (sMethod.getParameter(sMethod.getParameters().size() - 1) != sParameter) { methodBuilder.append(", "); } x++; } methodBuilder.append("}"); } methodBuilder.append(");"); methodBuilder.append("}"); method.setBody(methodBuilder.toString()); reflectorImplClass.addMethod(method); } writeClassFile(reflectorImplClass); pool.toClass(reflectorImplClass, getClass().getClassLoader(), getClass().getProtectionDomain()); } catch (Exception e) { LOGGER.error("", e); } } private void build2(Class<? extends PublicInterface> interfaceClass, org.bimserver.shared.meta.SService sService) { try { CtClass reflectorImplClass = pool.makeClass(GENERATED_CLASSES_PACKAGE + "." + interfaceClass.getSimpleName() + "Reflector" + implementationCounter); CtClass reflectorClass = pool.get(Reflector.class.getName()); CtClass interfaceCtClass = pool.get(interfaceClass.getName()); reflectorImplClass.addInterface(reflectorClass); CtField reflectorField = new CtField(interfaceCtClass, "publicInterface", reflectorImplClass); reflectorImplClass.addField(reflectorField); CtConstructor constructor = new CtConstructor(new CtClass[] { interfaceCtClass }, reflectorImplClass); StringBuilder sb = new StringBuilder(); reflectorImplClass.addConstructor(constructor); sb.append("{"); sb.append("this.publicInterface = $1;"); sb.append("}"); constructor.setBody(sb.toString()); CtClass[] parameters = new CtClass[4]; parameters[0] = pool.get(String.class.getName()); parameters[1] = pool.get(String.class.getName()); parameters[2] = pool.get(Class.class.getName()); parameters[3] = pool.get(KeyValuePair.class.getName() + "[]"); CtMethod method = new CtMethod(pool.get(Object.class.getName()), "callMethod", parameters, reflectorImplClass); StringBuilder methodBuilder = new StringBuilder(); methodBuilder.append("{"); methodBuilder.append("if (1==0) {} "); for (SMethod sMethod : sService.getMethods()) { methodBuilder.append(" else if ($2.equals(\"" + sMethod.getName() + "\")) {"); if (!sMethod.getReturnType().isVoid()) { methodBuilder.append("return "); } methodBuilder.append("publicInterface." + sMethod.getName() + "("); int i = 0; for (SParameter sParameter : sMethod.getParameters()) { methodBuilder.append("(" + sParameter.getType().toJavaCode() + ")$4[" + i + "].getValue()"); if (i < sMethod.getParameters().size() - 1) { methodBuilder.append(", "); } i++; } methodBuilder.append(");"); methodBuilder.append("}"); } methodBuilder.append("return null;"); methodBuilder.append("}"); method.setBody(methodBuilder.toString()); reflectorImplClass.addMethod(method); writeClassFile(reflectorImplClass); pool.toClass(reflectorImplClass, getClass().getClassLoader(), getClass().getProtectionDomain()); } catch (Exception e) { LOGGER.error("", e); } } }