Club of anonimous developers "Refactoring: Legacy code"

Refactoring: LegacyThe True Hacker's Guide To The Legacy

What is...Very old projects, had been written long long ago.

Mature projects, optimization required.

Die hard, nobody knows why it is still alive.

Market victim, nobody wants this sh%t anymore.

Problem child, nobody loves it.

Every project in active long term support.What is usually NOT...Badly written projects which are not in production.

Low quality designed projects.

Every project you don't understand.What do we need?Legacy project.

Developers who want refactor it.

A customer eager to pay for it.

Open mind – for everything else and many moreMigration #1: from TOM to POM<target name="generate.libs" depends="init" unless="ignore.generate.libdep" description="Generate library dependencies"> <mkdir dir="${build}/svn-checkout"/>  <ant inheritAll="false"antfile="${build.config.dir}/svnsupport.xml" target="checkout"> <property name="svn.username" value="${svn.username}"/> <property name="svn.password" value="${svn.password}"/> <property name="svn.url" value="${svn.url.eterracore}"/> <property name="svn.target.dir" value="${build}/svn-checkout"/> </ant>  <ant inheritAll="false"antfile="${build}/svn-checkout/build.xml" target="jar"> </ant> <copy todir="${libdep.dir}"> <fileset dir="${build}/svn-checkout/build/"> <include name="*.jar"/> </fileset> </copy></target><modules> <module>core</module> <module>demo</module> <module>noncla</module> <module>protocol/bayeux</module> <module>protocol/dwrp</module> <module>protocol/json</module> <module>serverside/guice</module> <module>serverside/hibernate</module> <module>serverside/hibernate2</module> <module>serverside/spring</module> <module>serverside/struts</module> <module>serverside/various</module> <module>serverside/webwork</module> <module>ui/dojo</module> <module>ui/dwr</module> <module>ui/gi</module> <module>ui/jaxer</module> <module>ui/scriptaculous</module> </modules>

Migration #2: IoC (DI) FTWpublic class BlockDefService { private static Logger logger = Logger.getLogger(BlockDefService.class); public static final int MIN_DURATION = 4; public static List<BlockDef> getBlockDefList(final BlockDefParamsparams) { return BlockDefQueries.getBlockDefList(params); } public staticBlockDefloadBlockDef(final Long blockDefId) { return BlockDefQueries.loadBlockDef(blockDefId); } public static void deleteBlockDef(final Long blockDefId) throws PartyException { … }public class BlockDefBusiness { public static final int MIN_DURATION = 4; private static final Logger LOG = Logger.getLogger(BlockDefBusiness.class); private PartyDaopartyDao; private BlockDefDaoblockDefDao; private PartyRoleDaopartyRoleDao; public List<BlockDef> getBlockDefList(GregorianCalendarcurrentDay, Long partyId) { return blockDefDao.getBlockDefList(currentDay, partyId); } public BlockDefloadBlockDef(Long blockDefId) { return blockDefDao.loadBlockDef(blockDefId); } public void deleteBlockDef(Long blockDefId) throws PartyException { … }

Migration #3: AOP drivenActionForward forward = null;try { // updateScreenCode(request); if (isTransactionable()) {TransactionManager.beginTransaction(); }forward = executeAction(mapping, form, req, res); if (isTransactionable()) {TransactionManager.commit(); }} catch (NullPointerException e) {// TODO It is not goodLOG.error("NPE error in the action", e); forward = mapping.findForward(SYSTEM_ERROR);} catch (ModuleException e) {LOG.error(e.getMessage(), e); throw e;} catch (BusinessException e) {LOG.error(e.getMessage(), e); throw e;} catch (Throwable e) {LOG.error("Error in the action", e); forward = mapping.findForward(SYSTEM_ERROR);}ActionForward forward = executeAction(mapping, form, req, res);…<bean id="failAdvice" class="eterra.sr.service.FailAdvice“/><tx:advice id=“interceptor" transaction-manager="trManager"> <tx:attributes> <tx:method name="save*" propagation="REQUIRED"/> <tx:method name="load*" propagation="REQUIRED"/> <tx:method name="do*" propagation="REQUIRED"/> <tx:method name="get*" propagation="SUPPORTS" read-only="true"/> </tx:attributes></tx:advice><aop:config> <aop:pointcut id=“actionClasses" expression=“…"/> <aop:advisor advice-ref=“interceptor" pointcut-ref=“actionClasses" order="10"/> <aop:aspect ref="failAdvice" order="1"> <aop:around method="aroundTransactional" pointcut-ref=“actionClasses"/> </aop:aspect></aop:config>

Migration #4: Update librariesPros:Newer versions usually better optimized so you will get performance for free.

Newer versions have better different integration options.

Newer versions can provide richer API sufficient to compete task better/faster/easier.Cons:Newer versions can be incompatible with: JDK, other libraries, old configuration files etc.Migration #5: Code cleanupCollections.sort(list, new Comparator() { public int compare(Object o1, Object o2) {int value; Offer offer1 = (Offer) ((TradeConfirmation) o1).getOffer(); Offer offer2 = (Offer) ((TradeConfirmation) o2).getOffer(); if (offer1.getTradingInterval() < offer2.getTradingInterval()) { value = -1; } else { if (offer1.getTradingInterval() == offer2.getTradingInterval()) { if (offer1.getType() < offer2.getType()) { value = -1; } else { if (offer1.getType() == offer2.getType()) {PartyDef party1 = offer1.getParty().getEffectiveParty(deliveryD);PartyDef party2 = offer2.getParty().getEffectiveParty(deliveryD); if (party1.getName().compareTo(party2.getName()) < 0) { value = -1; } else { if (party1.getName().compareTo(party2.getName()) == 0) { if (offer1.getTradingZone().getEffectiveTradingDef(deliveryD).getIdentification().compareTo(…) < 0) { value = -1; } else { if (offer1.getTradingZone().getEffectiveTradingDef(deliveryD).getIdentification(…)) == 0) { value = 0; } else { value = 1; } } } else { value = 1; } } } else { value = 1; } } } else { value = 1; } } return value; } });

Club of anonimous developers "Refactoring: Legacy code"

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Club of anonimous developers "Refactoring: Legacy code"