/*
 * Copyright 2015 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * 
 *      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.drools.compiler.compiler;

import org.kie.internal.builder.KnowledgeBuilder;
import org.kie.internal.utils.ServiceRegistryImpl;


public class ProcessBuilderFactory {

    private static final String PROVIDER_CLASS = "org.jbpm.process.builder.ProcessBuilderFactoryServiceImpl";

    private static IllegalArgumentException initializationException;
    private static ProcessBuilderFactoryService provider = initializeProvider();

    public static ProcessBuilder newProcessBuilder(KnowledgeBuilder kBuilder) {
        if (initializationException != null) {
            // KnowledgeBuilderImpl expects an exception to report the origin of the failure
            throw initializationException;
        } else if (getProcessBuilderFactoryService() == null) {
            return null;
        } else {
            return getProcessBuilderFactoryService().newProcessBuilder(kBuilder);
        }
    }

    public static void setProcessBuilderFactoryService(ProcessBuilderFactoryService provider) {
        ProcessBuilderFactory.provider = provider;
    }

    private static ProcessBuilderFactoryService initializeProvider() {
        ProcessBuilderFactoryService service = null;
        try {
            ServiceRegistryImpl.getInstance().addDefault(ProcessBuilderFactoryService.class, PROVIDER_CLASS);
            service = ServiceRegistryImpl.getInstance().get(ProcessBuilderFactoryService.class);
            setProcessBuilderFactoryService(ServiceRegistryImpl.getInstance().get(ProcessBuilderFactoryService.class ) );
        } catch (IllegalArgumentException e) {
            initializationException = e;
            // intentionally ignored
        }
        return service;
    }

    /**
     * This method is used in jBPM OSGi Activators as we need a way to force re-initialization when starting
     * the bundles.
     */
    public static synchronized  void reInitializeProvider() {
        // reset the possible initialization exception captured before
        initializationException = null;
        provider = initializeProvider();
    }

    public static ProcessBuilderFactoryService getProcessBuilderFactoryService() {
        return provider;
    }

    public static synchronized void loadProvider(ClassLoader cl) {
        if (provider == null) {
            try {
                provider = (ProcessBuilderFactoryService)Class.forName(PROVIDER_CLASS, true, cl).newInstance();
            } catch (Exception e) { }
        }
    }

}