BindingDefaults.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 java.util.ArrayList;
import java.util.List;

import com.google.gwt.core.ext.BadPropertyValueException;
import com.google.gwt.core.ext.GeneratorContext;
import com.google.gwt.core.ext.TreeLogger;

/**
 * compile-time defaults
 *
 * with this class it will be possible to take part of the generation process of restserviceimpl
 * classes. by default there are no additional resolvers registered, you can add some if wanted.
 *
 * @see <a href='http://code.google.com/p/google-web-toolkit/wiki/MultiValuedConfigProperties'>MultiValuedConfigProperties</a>
 * @author abalke
 *
 */
public class BindingDefaults {
    /**
     * additional AnnotationResolvers, added by {@link #addAnnotationResolver(AnnotationResolver)}
     */
    private static final List<AnnotationResolver> annotationResolvers = new ArrayList<AnnotationResolver>();

    /**
     * to avoid returning different Sets of AnnotationResolvers by false
     * usage, the return of the first call to {@link #getAnnotationResolvers()}
     * is cached here.
     *
     * if there will be a call to {@link #addAnnotationResolver(AnnotationResolver)} after
     * that first call, we will throw a runtime exception to avoid nasty bugs.
     */
    private static List<AnnotationResolver> _annotationResolversRequested = null;

    /**
     * access all annotationresolvers that are registered
     *
     * @return a copy of all AnnotationResolvers
     */
    public static List<AnnotationResolver> getAnnotationResolvers(final GeneratorContext context,
            final TreeLogger logger) {

        // do this only the first time call
        if(null == _annotationResolversRequested) {
            // call additional AnnotationResolvers if there are some configured
            try {
                for (String className : context.getPropertyOracle()
                        .getConfigurationProperty("org.fusesource.restygwt.annotationresolver").getValues()) {
                    logger.log(TreeLogger.INFO, "classname to resolve: " + className);
                    Class<?> clazz = null;

                    try {
                        clazz = Class.forName(className);
                    } catch (ClassNotFoundException e) {
                        new RuntimeException("could not resolve class " + className + " "
                                + e.getMessage());
                    }

                    if (null != clazz) {
                        try {
                            logger.log(TreeLogger.INFO, "add annotationresolver: " + clazz.getName());
                            addAnnotationResolver((AnnotationResolver) clazz.newInstance());
                        } catch (InstantiationException e) {
                            new RuntimeException("could not instanciate class " + className + " "
                                    + e.getMessage());
                        } catch (IllegalAccessException e) {
                            new RuntimeException("could not access class " + className + " "
                                    + e.getMessage());
                        }
                    } else {
                        throw new RuntimeException("could not create instance for classname " + className);
                    }
                }
            } catch (BadPropertyValueException ignored) {
                /*
                 *  ignored since there is no
                 *
                 *  <set-configuration-property name="org.fusesource.restygwt.annotationresolver"
                 *          value="org.fusesource.restygwt.rebind.ModelChangeAnnotationResolver"/>
                 */
                logger.log(TreeLogger.DEBUG, "no additional annotationresolvers found");
            }
        }

        // return a copy
        List<AnnotationResolver> ret = new ArrayList<AnnotationResolver>();

        for (AnnotationResolver a : annotationResolvers) {
            ret.add(a);
        }
        return _annotationResolversRequested = ret;
    }

    /**
     * access all annotationresolvers that are registered
     */
    public static void addAnnotationResolver(AnnotationResolver ar) {
        if (_annotationResolversRequested != null) {
            throw new RuntimeException("Sorry, you cannot add more AnnotationResolver instances after the first time " +
                    "`BindingDefaults#getAnnotationResolvers´ has been called. please check your runtime logic.");
        }
        annotationResolvers.add(ar);
    }
}