GwtJacksonEncoderDecoderClassCreator.java

/**
 * Copyright (C) 2009-2012 the original author or authors.
 * See the notice.md file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * 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.fusesource.restygwt.rebind;

import com.fasterxml.jackson.annotation.JsonValue;
import com.github.nmorel.gwtjackson.client.ObjectMapper;
import com.google.gwt.core.client.GWT;
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.JMethod;
import com.google.gwt.json.client.JSONParser;
import com.google.gwt.json.client.JSONString;
import com.google.gwt.json.client.JSONValue;
import com.google.gwt.user.rebind.ClassSourceFileComposerFactory;

/**
 *
 * @author lucasam
 *
 *         Based on @see
 *         corg.fusesource.restygwt.rebind.JsonEncoderDecoderClassCreator
 *
 */

public class GwtJacksonEncoderDecoderClassCreator extends BaseSourceCreator {
	private static final String GWT_JACKSON_ENCODER_SUFFIX = "_Gen_GwtJackEncDec_";
	private static final String GWT_JACKSON_MAPPER_IF = "GwtJackMapper";

	private static final String OBJECT_MAPPER_CLASS = ObjectMapper.class.getName();

	protected static final String JSON_VALUE_CLASS = JSONValue.class.getName();
	protected static final String JSON_STRING_CLASS = JSONString.class.getName();


	protected boolean javaBeansNamingConventionEnabled;

	public GwtJacksonEncoderDecoderClassCreator(TreeLogger logger, GeneratorContext context, JClassType source) {
		super(logger, context, source, GWT_JACKSON_ENCODER_SUFFIX);
	}

	@Override
	public void generate() throws UnableToCompleteException {
		//Forcing class to be loaded
		try {
			Class.forName(ObjectMapper.class.getName());
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
		final JClassType sourceClazz = source.isClass() == null ? source.isInterface() : source.isClass();
		if (sourceClazz == null) {
			getLogger().log(ERROR, "Type is not a class");
			throw new UnableToCompleteException();
		}
		generateMapper();
		generateSingleton(shortName);
		generateEncodeMethod(source);
		generateDecodeMethod(source);
	}

	private void generateMapper() {
		p();
		p("public static interface " + GWT_JACKSON_MAPPER_IF + " extends " + OBJECT_MAPPER_CLASS + "<"
				+ source.getParameterizedQualifiedSourceName() + "> {};");
		p();
	}

	protected void generateSingleton(String shortName) {
		p();
		p("public static final " + shortName + " INSTANCE = new " + shortName + "();");
		p();
	}

	@Override
	protected ClassSourceFileComposerFactory createComposerFactory() {
		ClassSourceFileComposerFactory composerFactory = new ClassSourceFileComposerFactory(packageName, shortName);
		composerFactory.setSuperclass(JsonEncoderDecoderInstanceLocator.JSON_ENCODER_DECODER_CLASS + "<"
				+ source.getParameterizedQualifiedSourceName() + ">");
		return composerFactory;
	}

	private void generateEncodeMethod(JClassType classType) {

		p("public " + JSON_VALUE_CLASS + " encode(" + source.getParameterizedQualifiedSourceName() + " value) {").i(1);

		{
			p("if( value==null ) {").i(1);
			{
				p("return getNullType();");
			}
			i(-1).p("}");

			p(GWT_JACKSON_MAPPER_IF + " mapper__ = "+GWT.class.getName()+".create(" + GWT_JACKSON_MAPPER_IF + ".class);");
			p(" String returnStr = mapper__.write(value);");
			p("return " + JSONParser.class.getName() + ".parseLenient(returnStr);");
		}
		i(-1).p("}");
		p();
	}

	protected String getValueMethod(JClassType classType) {
		String method = "name";
		for (JMethod jm : classType.isEnum().getMethods()) {
			if (jm.isAnnotationPresent(JsonValue.class)) {
				method = jm.getName();
				break;
			}
		}
		return method;
	}

	private void generateDecodeMethod(JClassType classType) {
		p("public " + source.getParameterizedQualifiedSourceName() + " decode(" + JSON_VALUE_CLASS + " value) {").i(1);
		{
			p("if( value == null || value.isNull()!=null ) {").i(1);
			{
				p("return null;").i(-1);
			}
			p("}");


			p(GWT_JACKSON_MAPPER_IF + " mapper__ = "+GWT.class.getName()+".create(" + GWT_JACKSON_MAPPER_IF + ".class);");
			p(" return (" + source.getParameterizedQualifiedSourceName() + ") mapper__.read(value.toString());");

			i(-1).p("}");
			p();
		}
	}

}