org.fornax.cartridges.sculptor.framework.drools.DroolsAdvice.java Source code

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Here is the source code for org.fornax.cartridges.sculptor.framework.drools.DroolsAdvice.java

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/*
 * (C) Copyright Factory4Solutions a.s. 2009
 *
 * 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.fornax.cartridges.sculptor.framework.drools;

/**
 * This advice should be used to wave Drools to service calls
 *
 * @author Ing. Pavel Tavoda
 */
import java.util.ArrayList;
import java.util.Calendar;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;

import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.drools.agent.KnowledgeAgent;
import org.drools.agent.KnowledgeAgentFactory;
import org.drools.command.Command;
import org.drools.command.CommandFactory;
import org.drools.io.ResourceChangeScannerConfiguration;
import org.drools.io.ResourceFactory;
import org.drools.runtime.StatelessKnowledgeSession;
import org.fornax.cartridges.sculptor.framework.errorhandling.ServiceContext;
import org.fornax.cartridges.sculptor.framework.errorhandling.ServiceContextStore;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

public class DroolsAdvice implements MethodInterceptor, ApplicationContextAware {
    private static final Logger log = LoggerFactory.getLogger(DroolsAdvice.class);

    private ApplicationContext appContext;
    private KnowledgeAgent kagent;

    int updateInterval = 300; // 5 min
    String ruleSet = "/CompanyPolicy.xml";
    boolean catchAllExceptions = false;

    public Object invoke(MethodInvocation procJointpoint) throws Throwable {
        long startTimeExec = System.currentTimeMillis();
        log.info("############# START DROOLS RULES");
        RequestDescription req = new RequestDescription(procJointpoint);
        try {
            Object[] arguments = procJointpoint.getArguments();
            ServiceContext ctx;
            int startArg;
            if (arguments[0] instanceof ServiceContext) {
                ctx = (ServiceContext) arguments[0];
                startArg = 1;
            } else {
                ctx = ServiceContextStore.get();
                startArg = 0;
            }

            HashMap<String, Object> objects = new HashMap<String, Object>();
            for (int i = startArg; i < arguments.length; i++) {
                objects.put("arg" + i, arguments[i]);
            }
            objects.put("request", req);
            objects.put("service", procJointpoint.getThis());
            objects.put("username", ServiceContextStore.getCurrentUser());

            HashMap<String, Object> globals = new HashMap<String, Object>();
            if (ctx != null) {
                globals.put("serviceContext", ctx);
            }
            globals.put("appContext", appContext);
            globals.put("log", log);

            Calendar curDate = Calendar.getInstance();
            globals.put("currentDate", curDate);
            globals.put("currentTimestamp", curDate.getTimeInMillis());

            applyCompanyPolicy(objects, globals);
        } catch (Throwable th) {
            if (catchAllExceptions) {
                while (th.getCause() != null) {
                    th = th.getCause();
                }
                log.warn("Applying company policy finished with error: " + th.getMessage(), th);
            } else {
                throw th;
            }
        } finally {
            log.info("############# END DROOLS RULES (" + (System.currentTimeMillis() - startTimeExec) + " ms)");
        }

        if (req.wasProceed() && req.getLastResult() != null && req.getLastResult() instanceof Throwable) {
            throw (Throwable) req.getLastResult();
        } else if (req.wasProceed()) {
            return req.getLastResult();
        } else {
            return procJointpoint.proceed();
        }
    }

    private void applyCompanyPolicy(HashMap<String, Object> objects, HashMap<String, Object> globals) {
        if (kagent == null) {
            synchronized (DroolsAdvice.class) {
                if (kagent == null) {
                    KnowledgeAgent unconfigAgent = KnowledgeAgentFactory.newKnowledgeAgent("CompanyPolicyAgent");
                    unconfigAgent.applyChangeSet(ResourceFactory.newClassPathResource(getDroolsRuleSet()));

                    ResourceChangeScannerConfiguration sconf = ResourceFactory.getResourceChangeScannerService()
                            .newResourceChangeScannerConfiguration();
                    sconf.setProperty("drools.resource.scanner.interval", Integer.toString(getUpdateInterval()));
                    ResourceFactory.getResourceChangeScannerService().configure(sconf);
                    ResourceFactory.getResourceChangeNotifierService().start();
                    ResourceFactory.getResourceChangeScannerService().start();

                    kagent = unconfigAgent;
                }
            }
        }

        StatelessKnowledgeSession slSession = kagent.newStatelessKnowledgeSession();
        List<Command<?>> cmds = new ArrayList<Command<?>>();
        if (globals != null && globals.size() > 0) {
            for (Iterator<String> keys = globals.keySet().iterator(); keys.hasNext();) {
                String key = keys.next();
                cmds.add(CommandFactory.newSetGlobal(key, globals.get(key)));
            }
        }

        if (objects != null && objects.size() > 0) {
            for (Iterator<String> keys = objects.keySet().iterator(); keys.hasNext();) {
                String key = keys.next();
                cmds.add(CommandFactory.newInsert(objects.get(key), key));
            }
        }
        // For stateless sesion is automatic
        // cmds.add(CommandFactory.newFireAllRules());

        slSession.execute(CommandFactory.newBatchExecution(cmds));
    }

    public int getUpdateInterval() {
        return updateInterval;
    }

    public void setUpdateInterval(int updateInterval) {
        this.updateInterval = updateInterval;
    }

    public String getDroolsRuleSet() {
        return ruleSet;
    }

    public void setDroolsRuleSet(String ruleSet) {
        this.ruleSet = ruleSet;
    }

    public boolean getCatchAllExceptions() {
        return catchAllExceptions;
    }

    public void setCatchAllExceptions(boolean catchAllExceptions) {
        this.catchAllExceptions = catchAllExceptions;
    }

    /**
     * Dependency injection, ApplicationContextAware.
     */
    public void setApplicationContext(ApplicationContext appContext) throws BeansException {
        this.appContext = appContext;
    }
}