HÖNNUN OG SMÍÐI HUGBÚNAÐAR 2015L09 PROCESS DESIGN

Agenda

Why processes?Ru FrameworkRU Process Framework ImplementationImport Content Process

Why Processes?

What is a Processes anyway?▪ Enterprise system need to run processes for several

reasons– Manual, event-driven, scheduled▪ Things in the “background”, for exampe:– Nightly update of customers– Reconciliation of systems▪ Lengthy operations– Recalculate of all accounts▪ Processes have no user interface– Traditionally know as “Jobs”

Our Task

We need to build a framework from running processesWhat patterns can we use?

Design Issues▪ Each process has simple task▪ Each process can be re-run at any time▪ Locations are always the same▪ Logging is always the same▪ Customer specific functionality

can be added to generic processes▪ Other considerations– Must handle large amount of data– Must support multiple threads for performance

Process Framework

Generic Process

Customer Specific Plugin

RU Framework

RU Framework▪ Simple Framework developed during the course– Illustrates design ideas– Application Framework– Reduce dependence on other frameworks by wrapping

them in interfaces and classes– Builds on Spring▪ Package– is.ruframework• domain• process– All classes are prefixed with “Ru”

▪ The idea is that the Process Framework starts the process▪ Process Developers must implement some interface▪ Information will be in a context XML file

Process Framework

Process Framework

processContext.xmlProcess Class

read CreateCall methods

Process Design▪ Let’s create an interface, RuProcess– This is what all processes have to implement

package is.ruframework.process;

public interface RuProcess { public void startProcess (); public void beforeProcess (); public void afterProcess (); }

Process Design▪ Let’s implement this with RuAbstractProcess– Processes can extend this classes – Layer Supertype

package is.ruframework.process;

import is.ruframework.domain.RuObject;

abstract public class RuAbstractProcess extends RuObject implements RuProcess { abstract public void startProcess (); public void beforeProcess () { } public void afterProcess () { } }

Process Design▪ We needs some context, RuProcessContext– Processes can get information about their process from this

context

public class RuProcessContext { private String processName; private String processClass; private String importFile; private String importURL; private String dataSourceFile; private Map params;

... }

Process Design▪ Let’s change the interface, RuProcess

– Dependency Injection

package is.ruframework.process;

public interface RuProcess { public void setProcessContext (RuProcessContext processContext); public void setParameters(String[] params); abstract public void startProcess (); public void beforeProcess (); public void afterProcess (); }

▪ Change the RuAbstractProcess– Let this class implement the injection

abstract public class RuAbstractProcess extends RuObject implements RuProcess { private RuProcessContext processContext; private String contextFile; private String parameters[]; ... public void setProcessContext(RuProcessContext processContext) { this.processContext = processContext; } ...

Process Design

▪ Let’s use a factory to create the process, RuProcessFactory– This class can load the context file

public class RuProcessFactory { private String contextFile; private RuProcessContext processContext;

public RuProcess loadProcess(RuProcessContext ctx) throws RuProcessException public void loadProcessContext(String contextFile) throws RuProcessException ... }

Process Design

▪ Create a class to run the process, RuProcessRunner– This class puts everything together

public class RuProcessRunner extends RuObject implements Runnable { private RuProcess process = null;

public static void main(String[] args) { } public RuProcessRunner(String contextFile) throws RuProcessException public void run() { } }

Process Design

RU Process Framework Implementation

Process Framework▪ To create process, we must

– Create the process class that implements RuProcess– Create the Process Context XML file

Process Framework

processContext.xmlProcess Class

read CreateCall methods

Process Context XML file▪ The framework will create the object RuProcessContext

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" http://www.springframework.org/dtd/spring-beans.dtd> <beans> <bean id="processContext” class="is.ruframework.process.RuProcessContext"> <property name="processName"> <value>RSSProcess</value> </property> <property name="importURL"> <value>http://rss.news.yahoo.com/rss/tech</value> </property> <property name="processClass"> <value>is.ru.honn.blog.process.RssReaderProcess</value> </property> </bean> </beans>

RuProcessContext

▪ Class for storing the Process Context– The environment the process runs in– Attributes line process name, class, importURL, data source

The RuProcess Interface▪ RuProcess is the interface for all processes▪ The framework will load the process context and set

with setProcessContext– Dependency Injection▪ The Framework will call the process methods– beforeProcess, startProcess, afterProcess

RuProcess▪ RuProcess is the interface for all processes

– The Process Factory will call setProcessContext

public interface RuProcess { public void setProcessContext(RuProcessContextprocessContext); public void setParameters(String[] params); public void startProcess (); public void beforeProcess (); public void afterProcess (); }

RuAbstractProcess▪ Abstract class that implements RuProcess

– Takes care of handling Process Context– Overrides beforeProcess

and afterProcess with empty methods, allowing them to become optional

– Declares startProcessas abstract

Template Method▪ Interface defines the methods needed

– Some are generic for all derived classes▪ Use abstract super classes to implement some but not all of

the interface methods

InterfacemethodA methodB

abstract super classmethodA

abstract methodB

Concrete classmethodB

implements

extends

RuAbstractProcessabstract public class RuAbstractProcess extends RuObject implements RuProcess { private RuProcessContextprocessContext; private String contextFile; private String parameters[];

public void setProcessContext(RuProcessContextprocessContext) { this.processContext = processContext; }

public RuProcessContextgetProcessContext() { return processContext; } ... abstract public void startProcess (); public void beforeProcess () {} public void afterProcess () {} }

Eat these methods

RuProcessFactory▪ Factory that loads processes

– Factroy and Plugin Patterns– loadProcess method returns RuProcess– Extends the generic RuFactory

RuProcessFactorypublic class RuProcessFactory extends RuFactory { private static final String PROCESS_CONTEXT = "process.xml"; private RuProcessContextprocessContext;

public RuProcessloadProcess(RuProcessContextctx) throws RuProcessException { RuProcess process = null;

// Load the process specified in the context file try { Class cls = Class.forName(ctx.getProcessClass()); process = (RuProcess)cls.newInstance(); process.setProcessContext(ctx); } catch (Exception e) { ... } return process; }

RuProcessFactory

public void loadProcessContext(String contextFile) throws RuProcessException { try { processContext = (RuProcessContext)getObject("processContext"); } catch (BeansException e) { String tmp = "File '" + contextFile + "' not found. Exception: " + e.getMessage(); log.severe(tmp); throw new RuProcessException(tmp, e); }

}

RuProcessRunner▪ Class that calls the factory and runs the process

– Name of Process Context file is parameter

public static void main(String[] args) { RuProcessRunner runner;

if (args.length> 0) { runner = new RuProcessRunner(args[0]); } else { runner = new RuProcessRunner(); }

try { runner.run(); } catch (RuProcessExceptionfwpe) { System.out.println(fwpe.getMessage()); } }

RuProcessRunner

public RuProcessRunner(String contextFile) throws RuProcessException { if (contextFile == null) { String tmp = "Parameter contextFile must not be null"; log.severe(tmp); throw new RuProcessException(tmp); } RuProcessFactory factory = new RuProcessFactory(contextFile); process = factory.loadProcess(); } public void run() { if (process != null) { process.beforeProcess(); process.startProcess(); process.afterProcess(); } } }

RuProcessRunner

Process Framework

Data Transfer Object

Factory

Plug-in

Layered Supertype

Dependency injection

Layered Supertype

Process Framework

Template Method

Import Content Process

Import Content Process▪ Problem– We need to import RSS feeds into our database– Example URL:

http://rss.news.yahoo.com/rss/tech

▪ Solution– Use the RU Framework• ImportContentPrcess– Use the FeedReader

Import Content Process▪ Process that reads contents from an URL▪ Tasks

– Creates a FeedReader to read entries– The process implements the processContent callback– Uses ContentService from our Domain Layer to store each

content– Must log out the progress using a message source

▪ Process that reads contents from an URL▪ Tasks

– The Process must “wire” all components together– Mapper Design Pattern

Import Content Process

Import ContentProcess

process.xml

uses

reads

FeedReader

ContentService

uses

app.xml

reads

▪ Process that reads contents from an URL▪ Solution

– Create class ImportContentProcess that extends RuAbstractProcessbeforeProcessstartProcessafterProcess

– Define the Process Context in process.xml– Use Spring ApplicationContext to load all the components

• Specified in app.xml

Import Content Process

public class ImportContentProcess extends RuAbstractProcess implements FeedHandler { protected ContentServicecontentService; FeedReader reader; MessageSourcemsg;

public void beforeProcess() { ApplicationContextctx = new FileSystemXmlApplicationContext("app.xml"); contentService = (ContentService)ctx.getBean("contentService"); reader = (FeedReader)ctx.getBean("feedReader"); reader.setFeedHandler(this); msg = (MessageSource)ctx.getBean("messageSource"); log.info(msg.getMessage("processbefore", new Object[] { getProcessContext().getProcessName() } , Locale.getDefault())); }

Import Content Process

ApplicationContextctx = new FileSystemXmlApplicationContext("app.xml"); contentService = (ContentService)ctx.getBean("contentService"); reader = (FeedReader)ctx.getBean("feedReader"); reader.setFeedHandler(this); msg = (MessageSource)ctx.getBean("messageSource");

<beans> <bean id="messageSource“ class= "org.springframework.context.support.ResourceBundleMessageSource"> <property name="basename“><value>messages</value></property> </bean> <bean id="contentService" class="is.ru.honn.tube.service.content.ContentServiceStub"> </bean> <bean id="feedReader" class="is.ru.honn.tube.feeds.RssReader"> </bean> </beans>

app.xml

Import Content ProcessImportContentProcess.java

public void startProcess() { log.info(msg.getMessage("processstart", new Object[] { getProcessContext().getProcessName() }, Locale.getDefault())); try { reader.read(getProcessContext().getImportURL()); } catch (FeedException e) { log.info(msg.getMessage("processreaderror", new Object[] { getProcessContext().getImportFile() }, Locale.getDefault())); log.info(e.getMessage()); } log.info(msg.getMessage("processstartdone", new Object[] {contentService.getContents().size()}, Locale.getDefault())); }

Import Content Process

Collecting the Entries public void processContent(Object content) { contentService.addContent((Content)content); }

Call-back Handler

Running the Process public void afterProcess() { Collection<Content>col = contentService.getContents(); for (Content cnt: col) { System.out.println(cnt); } }

Message Source

log.info(msg.getMessage("processstart", new Object[] { getProcessContext().getProcessName() }, Locale.getDefault()));

processbefore=The process {0} is starting (beforeProcess). processstart=Starting process {0} processstartdone=Reading done. Read {0} contents processreaderror=Unable to read file ''{0}''.

messages.properties

msg = (MessageSource)ctx.getBean("messageSource");

<bean id="messageSource“ class= "org.springframework.context.support.ResourceBundleMessageSource"> <property name="basename“><value>messages</value></property> </bean>

app.xml

startProcess in ImportContentProcess.java

beforeProcess in ImportContentProcess.java

Using the ContentService

public void processContent(Content content) { contentService.addContent(content); }

public interface ContentService { public void addContent(Content content); public Collection<Content>getContents(); }

while (i.hasNext()) { ent = (SyndEntry)i.next(); content = new Content(); content.setTitle(ent.getTitle()); ... handler.processContent(content); }

read in RssReader.java

ImportContentProcess.java

ContentService.java

Printing out values public void afterProcess() { Collection<Content>col = contentService.getContents(); for (Content cnt: col) { System.out.println(cnt); } }

INFO: The process ImportContentProcess is starting (beforeProcess). Sep 28, 2008 3:09:31 PM is.ru.honn.tube.process.ImportContentProcessstartProcess INFO: Starting process ImportContentProcess Sep 28, 2008 3:09:32 PM is.ru.honn.tube.process.ImportContentProcessstartProcess INFO: Reading done. Read 12 contents Japan's online social scene isn't so social (AP)

Unlocked iPhone 3G on sale in Hong Kong (AP)

Run with IntelliJ

Running the ProcessSep 13, 2015 1:14:45 PM org.springframework.context.support.FileSystemXmlApplicationContext prepareRefresh INFO: Refreshing org.springframework.context.support.FileSystemXmlApplicationContext@5ef04b5: startup date [Sun Sep 13 13:14:45 GMT 2015]; root of context hierarchy Sep 13, 2015 1:14:45 PM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions INFO: Loading XML bean definitions from file [/Users/Andri/Work/ImportContentProcess/process.xml] Sep 13, 2015 1:14:45 PM org.springframework.context.support.FileSystemXmlApplicationContext prepareRefresh INFO: Refreshing org.springframework.context.support.FileSystemXmlApplicationContext@31dc339b: startup date [Sun Sep 13 13:14:45 GMT 2015]; root of context hierarchy Sep 13, 2015 1:14:45 PM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions INFO: Loading XML bean definitions from class path resource [app.xml] Sep 13, 2015 1:14:45 PM is.ru.honn.tube.process.ImportContentProcess beforeProcess INFO: processbefore: ImportContentProcess Sep 13, 2015 1:14:45 PM is.ru.honn.tube.process.ImportContentProcess startProcess INFO: processstart: ImportContentProcess Prosecutors file charges against ex-CEO of Mt.Gox bitcoin exchange Sprint's plan for new iPhone trumps other U.S. carriers Obama says Chinese cyber practices are not acceptable, calls for faster U.S. response High-profile busts signal caution in start-up investing Court approves settlement over Curt Schilling's failed game studio What to look out for at the Frankfurt auto show Washington state fines a crowdfunding project for stiffing backers Go to the dark side of debt with this $28,500 'Star Wars' watch Self-destructing computer chip can protect top secret data iPhone 6s, 6s Plus Australian pricing Plex will bring its media streaming to Apple TV Professor says he's grateful feds dropped China secrets case

Summary▪ Process Framework▪ Import Content Process