Java tutorial
package ch.unifr.pai.twice.module.rebind; /* * Copyright 2013 Oliver Schmid * 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. */ import java.io.PrintWriter; import java.util.HashMap; import java.util.Map; import ch.unifr.pai.twice.module.client.TWICEAnnotations.Configurable; import ch.unifr.pai.twice.module.client.TWICEModule; import ch.unifr.pai.twice.module.client.TWICEModuleInstantiator; import com.google.gwt.core.client.GWT; import com.google.gwt.core.client.RunAsyncCallback; 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.JField; import com.google.gwt.core.ext.typeinfo.JPrimitiveType; import com.google.gwt.core.ext.typeinfo.NotFoundException; import com.google.gwt.user.client.rpc.AsyncCallback; import com.google.gwt.user.rebind.ClassSourceFileComposerFactory; import com.google.gwt.user.rebind.SourceWriter; /** * Generator logic applied at GWT compile time to create the instantiators for modules to establish the lazy loading mechanism * * @author Oliver Schmid * */ public class TWICEModuleGenerator extends Generator { /** * @param classType * @return the class type of the actual component widget provided through the generic annotation */ private JClassType getGenericClass(JClassType classType) { JClassType clazz = null; for (JClassType intf : classType.getImplementedInterfaces()) { if (intf.getQualifiedSourceName().equals(TWICEModule.class.getName())) { JClassType[] generics = intf.isParameterized().getTypeArgs(); // The twice module has only one generic for (JClassType g : generics) clazz = g; } } return clazz; } /* * (non-Javadoc) * @see com.google.gwt.core.ext.Generator#generate(com.google.gwt.core.ext.TreeLogger, com.google.gwt.core.ext.GeneratorContext, java.lang.String) */ @Override public String generate(TreeLogger logger, GeneratorContext context, String typeName) throws UnableToCompleteException { // Build a new class, that implements a "paintScreen" method JClassType classType; try { classType = context.getTypeOracle().getType(typeName); JClassType genericClass = getGenericClass(classType); SourceWriter src = getSourceWriter(classType, context, logger); if (src != null) { src.println("@Override"); src.println("public " + Map.class.getName() + "<" + String.class.getName() + ", " + Object.class.getName() + "> getConfigurableFields(" + genericClass.getQualifiedSourceName() + " instance){"); src.println(Map.class.getName() + "<" + String.class.getName() + ", " + Object.class.getName() + "> result = new " + HashMap.class.getName() + "<" + String.class.getName() + ", " + Object.class.getName() + ">();"); for (JField f : genericClass.getFields()) { Configurable c = f.getAnnotation(Configurable.class); if (c != null && !f.isFinal() && !f.isPrivate() && !f.isProtected()) { src.println("result.put(\"" + c.value() + "\", instance." + f.getName() + ");"); } } src.println("return result;"); src.println("}"); src.println("@Override"); src.println("public void configure(" + Map.class.getName() + "<" + String.class.getName() + ", " + String.class.getName() + "> properties, " + genericClass.getQualifiedSourceName() + " instance){"); src.println("for(" + String.class.getName() + " key : properties.keySet()){"); src.println("String value = properties.get(key);"); src.println("if(key==null){"); src.println("}"); for (JField f : genericClass.getFields()) { Configurable c = f.getAnnotation(Configurable.class); if (c != null && !f.isFinal() && !f.isPrivate() && !f.isProtected()) { JPrimitiveType t = f.getType().isPrimitive(); if (t != null) { src.println("else if(key.equals(\"" + c.value() + "\")){"); switch (t) { case INT: src.println("instance." + f.getName() + "=" + Integer.class.getName() + ".parseInt(value);"); break; case BOOLEAN: src.println("instance." + f.getName() + "=" + Boolean.class.getName() + ".parseBoolean(value);"); break; case DOUBLE: src.println("instance." + f.getName() + "=" + Double.class.getName() + ".parseDouble(value);"); break; case FLOAT: src.println("instance." + f.getName() + "=" + Float.class.getName() + ".parseFloat(value);"); break; case LONG: src.println("instance." + f.getName() + "=" + Long.class.getName() + ".parseLong(value);"); break; default: throw new RuntimeException("The primitive type \"" + t.name() + "\" is not supported for configuration"); } } else if (f.getType().getQualifiedSourceName().equals(String.class.getName())) { src.println("instance." + f.getName() + "=value"); } else { throw new RuntimeException("The type \"" + f.getType().getQualifiedSourceName() + "\" is not supported for configuration"); } src.println("}"); } } src.println("}"); src.println("}"); src.println("@Override"); src.println("public " + RunAsyncCallback.class.getName() + " instantiate(final " + AsyncCallback.class.getName() + "<" + genericClass.getQualifiedSourceName() + "> callback){"); src.println("return new " + RunAsyncCallback.class.getName() + "(){"); src.println("@Override"); src.println("public void onSuccess(){"); src.println(genericClass.getQualifiedSourceName() + " module = " + GWT.class.getName() + ".create(" + genericClass.getQualifiedSourceName() + ".class);"); src.println("//start(module);"); src.println("callback.onSuccess(module);"); src.println("}"); src.println("@Override"); src.println("public void onFailure(" + Throwable.class.getName() + " reason){"); src.println("callback.onFailure(reason);"); src.println("}"); src.println("};"); src.println("}"); src.commit(logger); } return typeName + "Impl"; } catch (NotFoundException e) { e.printStackTrace(); } return null; } /** * Define the class to be generated. * * @param classType * @param context * @param logger * @return */ public SourceWriter getSourceWriter(JClassType classType, GeneratorContext context, TreeLogger logger) { String packageName = classType.getPackage().getName(); String simpleName = classType.getSimpleSourceName() + "Impl"; ClassSourceFileComposerFactory composer = new ClassSourceFileComposerFactory(packageName, simpleName); composer.setSuperclass(classType.getName()); composer.addImplementedInterface(TWICEModuleInstantiator.class.getName() + "<" + getGenericClass(classType).getQualifiedSourceName() + ">"); PrintWriter printWriter = context.tryCreate(logger, packageName, simpleName); if (printWriter == null) { return null; } else { SourceWriter sw = composer.createSourceWriter(context, printWriter); return sw; } } }