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Ching Yi, Chan (qrtt1) OSGi 入門與簡介

WHAT IS OSGi ? The OSGi? specifications define a standardized, component-oriented, computing environment for networked services that is the foundation of an enhanced service-oriented architecture. Adding an OSGi Service Platform to a networked device (embedded as well as servers), adds the capability to manage the lifecycle of the software components in the device from anywhere in the network. Software components can be installed, updated, or removed on the fly without ever having to disrupt the operation of the device.

WHAT IS OSGi ? The OSGi? specifications define a standardized, component-oriented, computing environment for networked services that is the foundation of an enhanced service-oriented architecture. Adding an OSGi Service Platform to a networked device (embedded as well as servers), adds the capability to manage the lifecycle of the software components in the device from anywhere in the network. Software components can be installed, updated, or removed on the fly without ever having to disrupt the operation of the device. WHO CARE ?

今日焦點定義少一點心情好一點範例懂一點知識長一點略懂

Service Platform 以「服務」「模組」建構系統適合開發服務導向架構 (SOA) 的平台您可以使用 OSGi 發佈「服務」使用「服務」尋找「服務」

OSGi Services Example 縮短網址的服務以共通的 interface 發佈服務允許同時存在不同的實作可以即時選擇要使用的服務可以知道服務的狀態

Where is Service ? Service 建構在 Module 層之上受 Module Life cycle 影響在 Module 內使用 ServiceRegistry 註冊 Service 那麼， Bundle(App) 就能使用 Service

Quick Tutorial In Bundle OSGi 模組的基本單位建立 Bundle 的步驟寫一些類別 ! ？在 META/MANIFEST.MF 填些什麼？包成 JAR ! ？

Hello Bundle Activator & MANIFEST.MF Activator/hook method Start Stop MANIFEST.MF Make jug.hello bundle with Activator print hello & bye. Run and use start/stop.

Bundle - visibility 預設的 Bundle 是個黑盒子完整地保護無法窺視內部 Reflection Classloader trickery

Bundle - visibility 透過 Export-Package 分享 package Export-Package: jug.hello.api jug.hello.api

Bundle - visibility 透過 Import-Package 使用 package Import-Package: jug.hello.api B A import jug.hello.api .HelloWorld; class Foo{ public void hello(){ new HelloWorld().hello(); } } jug.hello.api

Bundle – package propety Bundle: jug.hello.api.v1 Export-Package: jug.hello.api; version ="1.0.0" Bundle: jug.hello.api.v2 Export-Package: jug.hello.api; version =“2.0.0"

Export-Package: jug.hello.api;version=“1.0.0” Export-Package: jug.hello.api;version=“2.0.0” jug.hello.api.v1 jug.hello.api.v2 jug.hello Import-Package: jug.hello.api Demo hello.api later 版本高者優先

Export-Package: jug.hello.api;version=“1.0.0” Export-Package: jug.hello.api;version=“2.0.0” jug.hello.api.v1 jug.hello.api.v2 jug.hello Import-Package: jug.hello.api;version=“[1.0.0,1.5.0]” Demo hello.api later 選則偏好的版本

Life Cycle Demo hello.api later INSTALLED RESOLVED UNINSTALLED ACTIVE STOPPING STARTING start stop

Life Cycle Change System Behavior In Runtime Demo remote Demo jug.hello.api (change import version)

OSGi Service & URL Shorten Bundle

Service Bundle shorten.api 僅提供 interface shorten.client Swing UI 使用者互動介面 shorten.orz 0rz.tw 短址服服

Service Registry BundleContext. registerService() ServiceRegistration registration ; Properties prop = new Properties(); prop.setProperty("name", "0rz.tw"); registration = context.registerService ( IShortenURL.class.getName() , new OrzURL(), prop);

Find All Service BundleContext. getServiceReferences () ServiceReference[] refs = context.getServiceReferences ( IShortenURL.class.getName() , null );

Service Filter (LDAP Filter) context. getAllServiceReferences ( IShortenURL.class.getName(), String. format ( "(name=%s)" , name) ); “ (name=0rz.tw)” “ (name=tinyurl)” 過濾含有屬性 name ，且值為 0rz.tw 的 Service 過濾含有屬性 name ，且值為 tinyurl 的 Service

Service Filter (LDAP Filter) 選擇具有 cn 屬性且值為 Babs Jensen 者 "(cn=Babs Jensen)" 以 ! 排除具有 cn 屬性且值為 Tim Howes 者 "(!(cn=Tim Howes))" 選擇具有 objectclass 屬性且值為 Persion 並且不含屬性 sn 值 Jensen 與屬性 cn 且值為 Babs J 開頭者 "(& (" + Constants.OBJECTCLASS + "=Person) (|(sn=Jensen)(cn=Babs J*)) )" "(o=univ*of*mich*)"

Service Tracker Monitor Service come and go ServiceTracker addingService() 當 Service 被發佈時觸發 removedService() 當 Service 被終止時觸發

tracker = new ServiceTracker(context, IShortenURL.class.getName(), null) { public Object addingService (ServiceReference reference) { ui.resetAvailableServiceList(context); ui.updateStatus(String.format("Service [%s] is available.", reference.getProperty("name"))); return super.addingService(reference); } public void removedService (ServiceReference reference, Object service) { ui.resetAvailableServiceList(context); ui.updateStatus(String.format("Service [%s] is unavailable.", reference.getProperty("name"))); super.removedService(reference, service); } }; tracker. open ();

你需要 OSGi 嗎？你的系統需要執行期改變行為嗎？你的系統提供的服務經常變動嗎？

導入 OSGi 的問題沿用 META/MANIFEST.MF, BUT … 「手工」撰寫 MANIFEST.MF 是自虐。有單行長度限制最後一行需要空行 Metadata 需要填的內容可能很多 Import-Package Export-Package …

Manifest-Version: 1.0 Created-By: 1.5.0_12 (Sun Microsystems Inc.) Bundle-License: http://www.apache.org/licenses/LICENSE-2.0.txt Import-Package: com.thoughtworks.xstream;version="[1.2.2, 2.0.0)";reso lution:=optional,com.thoughtworks.xstream.annotations;version="[1.2.2 , 2.0.0)";resolution:=optional,com.thoughtworks.xstream.converters;ve rsion="[1.2.2, 2.0.0)";resolution:=optional,com.thoughtworks.xstream. io;version="[1.2.2, 2.0.0)";resolution:=optional,com.thoughtworks.xst ream.io.json;version="[1.2.2, 2.0.0)";resolution:=optional,com.though tworks.xstream.io.xml;version="[1.2.2, 2.0.0)";resolution:=optional,j avax.jms;version="[1.1.0, 2.0.0)",javax.management,javax.management.j 2ee.statistics;version="[1.0.1, 2.0.0)",javax.management.openmbean,ja vax.management.remote,javax.naming,javax.naming.directory,javax.namin g.event,javax.naming.spi,javax.net,javax.net.ssl,javax.security.auth, javax.security.auth.callback,javax.security.auth.login,javax.security .auth.spi,javax.sql,javax.transaction;version="[1.0.1, 2.0.0)";resolu tion:=optional,javax.transaction.xa;version="[1.0.1, 2.0.0)";resoluti on:=optional,javax.xml.parsers,org.apache.activeio.journal;version="[ 3.1.0, 4.0.0)";resolution:=optional,org.apache.activeio.journal.activ e;version="[3.1.0, 4.0.0)";resolution:=optional,org.apache.activeio.p acket;version="[3.1.0, 4.0.0)";resolution:=optional,org.apache.camel; version="[1.3.0, 2.0.0)";resolution:=optional,org.apache.camel.compon

導入 OSGi 的問題 Bundle ClassLoader 真麻煩 !? 我想要把舊的專案搬到 OSGi 上？這是可行的但是，所有使用到的 Library 都必需轉成 Bundle 並且設 Export-Package 然後，你會開始抱怨。 OSGi Sucks. Daxx it. OSGi.

導入 OSGi 的問題 JARs ? Bundles 使用到的 Library 都已經轉成 OSGi Bundle 了嗎？ http:// www.springsource.com /repository/app 可能將它們的轉成 OSGi Bundle 嗎？ http://aqute.biz/Code/Bnd http://wiki.ops4j.org/confluence/display/ops4j/Pax 能否單純以 JAR 的型式使用 Bundle-ClassPath Bundle-ClassPath + Fa?ade Pattern ? OSGi Service

導入 OSGi 的問題問題在設計以 Fa?ade Pattern 隔離底層不需共用的 JARs 管理 Bundle Dependency ，管制共用的 Bundle org.apache.commons.* Spring 採介面 / 實作分離的設計，以 Service 建構系統。

導入 OSGi 的問題 OSGi Run many app in single vm 需要禁止任何終止 VM 活動的程式使用 SecurityManager ( 啟動 Security Layer 防護功能 ) System.exit(0);

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