InjectionHelper.java example

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/*
 * Copyright 2017 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.
 * 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.drools.compiler.kie.util;

import java.util.Map;

import org.drools.core.impl.InternalKnowledgeBase;
import org.kie.api.builder.model.KieSessionModel;
import org.kie.api.builder.model.ListenerModel;
import org.kie.api.builder.model.WorkItemHandlerModel;
import org.kie.api.event.process.ProcessEventListener;
import org.kie.api.event.rule.AgendaEventListener;
import org.kie.api.event.rule.RuleRuntimeEventListener;
import org.kie.api.runtime.KieSession;
import org.kie.api.runtime.StatelessKieSession;
import org.kie.api.runtime.process.WorkItemHandler;

public class InjectionHelper {

    private static class BeanCreatorHolder {
        private static final BeanCreator beanCreator = loadBeanCreator();

        private static BeanCreator loadBeanCreator() {
            BeanCreator beanCreator = lookupCdiBeanCreator();
            return beanCreator != null ? beanCreator : new ReflectionBeanCreator();
        }

        private static BeanCreator lookupCdiBeanCreator() {
            try {
                return (BeanCreator) Class.forName( "org.drools.cdi.CDIHelper" )
                                          .getMethod( "getCdiBeanCreator" ).invoke( null );
            } catch (Exception e) {
                return null;
            }
        }
    }

    public static void wireListnersAndWIHs(KieSessionModel model, KieSession kSession) {
        wireListnersAndWIHs(BeanCreatorHolder.beanCreator, model, kSession);
    }

    public static void wireListnersAndWIHs(KieSessionModel model, StatelessKieSession kSession) {
        wireListnersAndWIHs(BeanCreatorHolder.beanCreator, model, kSession);
    }

    public static void wireListnersAndWIHs( KieSessionModel model, KieSession kSession, Map<String, Object> parameters ) {
        wireListnersAndWIHs( new MVELBeanCreator( parameters), model, kSession );
    }

    public static void wireListnersAndWIHs(KieSessionModel model, StatelessKieSession kSession, Map<String, Object> parameters) {
        wireListnersAndWIHs(new MVELBeanCreator(parameters), model, kSession);
    }

    public static void wireListnersAndWIHs(BeanCreator beanCreator, KieSessionModel model, KieSession kSession) {
        BeanCreator fallbackBeanCreator = new ReflectionBeanCreator();
        ClassLoader cl = ((InternalKnowledgeBase)kSession.getKieBase()).getRootClassLoader();

        for (ListenerModel listenerModel : model.getListenerModels()) {
            Object listener = createListener( beanCreator, fallbackBeanCreator, cl, listenerModel );
            switch(listenerModel.getKind()) {
                case AGENDA_EVENT_LISTENER:
                    kSession.addEventListener((AgendaEventListener)listener );
                    break;
                case RULE_RUNTIME_EVENT_LISTENER:
                    kSession.addEventListener((RuleRuntimeEventListener)listener );
                    break;
                case PROCESS_EVENT_LISTENER:
                    kSession.addEventListener((ProcessEventListener)listener );
                    break;
            }
        }
        for (WorkItemHandlerModel wihModel : model.getWorkItemHandlerModels()) {
            WorkItemHandler wih;
            try {
                wih = beanCreator.createBean(cl, wihModel.getType(), wihModel.getQualifierModel());
            } catch (Exception e) {
                try {
                    wih = fallbackBeanCreator.createBean(cl, wihModel.getType(), wihModel.getQualifierModel() );
                } catch (Exception ex) {
                    throw new RuntimeException("Cannot instance WorkItemHandler " + wihModel.getType(), e);
                }
            }
            kSession.getWorkItemManager().registerWorkItemHandler(wihModel.getName(), wih );
        }
    }

    public static Object createListener( BeanCreator beanCreator, BeanCreator fallbackBeanCreator, ClassLoader cl, ListenerModel listenerModel ) {
        Object listener;
        try {
            listener = beanCreator.createBean(cl, listenerModel.getType(), listenerModel.getQualifierModel());
        } catch (Exception e) {
            try {
                listener = fallbackBeanCreator.createBean(cl, listenerModel.getType(), listenerModel.getQualifierModel());
            } catch (Exception ex) {
                throw new RuntimeException("Cannot instance listener " + listenerModel.getType(), e);
            }

        }
        return listener;
    }

    public static void wireListnersAndWIHs(BeanCreator beanCreator, KieSessionModel model, StatelessKieSession kSession ) {
        BeanCreator fallbackBeanCreator = new ReflectionBeanCreator();
        ClassLoader cl = ((InternalKnowledgeBase)kSession.getKieBase()).getRootClassLoader();

        for (ListenerModel listenerModel : model.getListenerModels()) {
            Object listener = createListener( beanCreator, fallbackBeanCreator, cl, listenerModel );
            switch(listenerModel.getKind()) {
                case AGENDA_EVENT_LISTENER:
                    kSession.addEventListener((AgendaEventListener)listener);
                    break;
                case RULE_RUNTIME_EVENT_LISTENER:
                    kSession.addEventListener((RuleRuntimeEventListener)listener);
                    break;
                case PROCESS_EVENT_LISTENER:
                    kSession.addEventListener((ProcessEventListener)listener);
                    break;
            }
        }
    }
}