OSGi容器中Bundle之间Synchronous Communication

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BluePrint
OSGi

osgi bean blueprint

OSGi Core定义了一个服务层，提供了一个Bundle之间交互的简单机制，通过注册Java Object 至OSGi service registry。 Blueprint Container

(1) Blueprint Configuration

默认配置文件位于：ProjectDir/src/main/resources/OSGI-INF/blueprint

默认XML文件命名空间：

Xml代码

<? xml version = "1.0" encoding = "UTF-8" ?>
< blueprint xmlns = "http://www.osgi.org/xmlns/blueprint/v1.0.0" >
...
</ blueprint >

自定义配置文件地址：

Bundle-Blueprint: lib/account.xml, security.bp, cnf/*.xml

Mandatory dependencies：

OSGi Service 中Dependencies默认是必须的，但可通过设置reference和reference-list元素的availability为optional

来改变这中现象。正常情况下，当Bluepring Container初始化时，通过一定范围的时间来允许Dependencies

Resolve, 该时间么哦人为：5秒，可通过下面的方式自定义：

Xml代码

Bundle-SymbolicName: org.fusesource.example.osgi-client;
blueprint.graceperiod: = true ;
blueprint.timeout: = 10000

(2) Defining a Service Bean

(3) Exporting a Service

1. Exporting with a single interface

Xml代码

< blueprint xmlns = "http://www.osgi.org/xmlns/blueprint/v1.0.0" >
< bean id = "savings" class = "org.fusesource.example.SavingsAccountImpl" />
< service ref = "savings" interface = "org.fusesource.example.Account" />
</ blueprint >

2. Exporting with multiple interfaces

Xml代码

< blueprint xmlns = "http://www.osgi.org/xmlns/blueprint/v1.0.0" >
< bean id = "savings" class = "org.fusesource.example.SavingsAccountImpl" />
< service ref = "savings" >
< interfaces >
< value > org.fusesource.example.Account </ value >
< value > org.fusesource.example.SavingsAccount </ value >
</ interfaces >
</ service >
</ blueprint >

注意：interface和interfaces不能同时在service元素中使用。

3. Exporting with auto-export

例如：下面的代码中Blueprint将自动注册所有SavingsAccountImpl实现的public接口：

Xml代码

< blueprint xmlns = "http://www.osgi.org/xmlns/blueprint/v1.0.0" >
< bean id = "savings" class = "org.fusesource.example.SavingsAccountImpl" />
< service ref = "savings" auto-export = "interfaces" />
</ blueprint >

其中auto-export默认值为：disabled,其他可选值为：

interfaces：注册该类实现的所有public的接口；

class-hierarchy：注册该类自己以及他的父类，但不包含Object类；

all-classes：注册该类自己以及他的父类，同时包括该类实现的接口。

4. Setting service properties

Xml代码

< blueprint xmlns = "http://www.osgi.org/xmlns/blueprint/v1.0.0" >
< bean id = "savings" class = "org.fusesource.example.SavingsAccountImpl" />
< service ref = "savings" auto-export = "interfaces" ranking = "10" >
< service-properties >
< beans:entry key = "bank.name" value = "HighStreetBank" />
</ service-properties >
</ service >
</ blueprint >

说明：A. 注册的service默认的Properties有：osgi.service.blueprint.compname值为service bean 的id

B. service.ranking 是系统自动设置。

C. 当系统查找服务时返回对个匹配的服务时，默认选择ranking值最高的服务，因此可配置该属性用以服务

之间的区分。

5. Specifying a registration listener

Xml代码

< blueprint xmlns = "http://www.osgi.org/xmlns/blueprint/v1.0.0" . >
< bean id = "listenerBean" class = "org.fusesource.example.Listener" />
< service ref = "savings" auto-export = "interfaces" >
< registration-listener ref = "listenerBean"
registration-method = "register" unregistration-method = "unregister" />
</ service >
</ blueprint >

Java代码

//Java
package org.fusesource.example;
public class Listener {
public void register(Account service, java.util.Map serviceProperties) {
}
public void unregister(Account service, java.util.Map serviceProperties) {
}
}

说明：register和unregister方法的参数，第一个参数可以是service class或service class 实现的接口，因为该

参数包含service instance, 如果该service bean 被声明为property, 在注册的时候是没有service instance可用

的，因此此时该参数的值为null.

第二个参数可以是java.util.Map或java.util.Dictionary，这个Map包含service 注册时的Properties.

(4) Importing a Service

使用reference和reference-list元素Import Service, 两者之间的区别是：reference用于访问stateless service,

而reference-list用于访问stateful service.

1. Matching by interface (stateless)

Xml代码

< blueprint xmlns = "http://www.osgi.org/xmlns/blueprint/v1.0.0" >
< reference id = "savingsRef" interface = "org.fusesource.example.SavingsAccount" />
< bean id = "client" class = "org.fusesource.example.client.Client" >
< property name = "savingsAccount" ref = "savingsRef" />
</ bean >
</ blueprint >

Java代码

package org.fusesource.example.client;
import org.fusesource.example.SavingsAccount;
public class Client {
SavingsAccount savingsAccount;
// Bean properties
public SavingsAccount getSavingsAccount() {
return savingsAccount;
}
public void setSavingsAccount(SavingsAccount savingsAccount) {
this .savingsAccount = savingsAccount;
}
}

2. Matching by interface (stateful)

Xml代码

< blueprint xmlns = "http://www.osgi.org/xmlns/blueprint/v1.0.0" >
< reference-list id = "savingsListRef"
interface = "org.fusesource.example.SavingsAccount" />
< bean id = "client" class = "org.fusesource.example.client.Client" >
< property name = "savingsAccountList" ref = "savingsListRef" />
</ bean >
</ blueprint >

Java代码

package org.fusesource.example.client;
import org.fusesource.example.SavingsAccount;
public class Client {
java.util.List<SavingsAccount> accountList;
// Bean properties
public java.util.List<SavingsAccount> getSavingsAccountList() {
return accountList;
}
public void setSavingsAccountList(java.util.List<SavingsAccount> accountList) {
this .accountList = accountList;
}
}

3. Matching service properties with a filter

Xml代码

< reference id = "savingsRef" interface = "org.fusesource.example.SavingsAccount" filter = "(bank.name=HighStreetBank)" />
< reference-list id = "savingsRef" interface = "org.fusesource.example.SavingsAccount" filter = "(bank.name=HighStreetBank)" />

4. Specifying whether mandatory or optional

默认值：mandatory

Xml代码

< reference id = "savingsRef" interface = "org.fusesource.example.SavingsAccount" availability = "mandatory" />

5. Specifying a reference listener

Xml代码

< blueprint xmlns = "http://www.osgi.org/xmlns/blueprint/v1.0.0" >
< reference id = "savingsRef" interface = "org.fusesource.example.SavingsAccount" >
< reference-listener bind-method = "onBind"
unbind-meth od = "onUnbind" >
< bean class = "org.fusesource.example.client.Listener" />
</ reference-listener >
</ reference >
< bean id = "client" class = "org.fusesource.example.client.Client" >
< property name = "savingsAcc" ref = "savingsRef" />
</ bean >
</ blueprint >

Java代码

package org.fusesource.example.client;
import org.osgi.framework.ServiceReference;
public class Listener {
public void onBind(ServiceReference ref) {
System.out.println("Bound service: " + ref);
}
public void onUnbind(ServiceReference ref) {
System.out.println("Unbound service: " + ref);
}
}

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2012-09-11 17:07
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