maven - 覆盖 Maven-Bundle-Plugin 中的 Require-Capability

Question

我的问题类似于this one但我使用 Maven 捆绑插件来实现相同的最终结果。

我正在构建一个包含 persistence.xml 的 bundle 文件，我发现 maven-bundle-plugin自动在 list 中生成以下 header :

Require-Capability:osgi.service;effective:=active;objectClass=javax.persistence.spi.PersistenceProvider;javax.persistence.provider=org.apache.openjpa.persistence.PersistenceProviderImpl,
Require-Capability: osgi.extender;osgi.extender=aries.jpa, 
Require-Capability: osgi.service;effective:=active;objectClass=javax.sql.DataSource;filter:="(osgi.jndi.service.name=jdbc/test)"

这本身不是问题，但是我正在使用 Karaf，并且我想在我自己的一个功能中部署这个和其他 bundle 以及 Karaf 功能。当我这样做时，它会失败，因为 OSGi 无法实现功能 osgi.service;effective:=active;objectClass=javax.persistence.spi.PersistenceProvider;javax.persistence.provider=org.apache.openjpa.persistence.PersistenceProviderImpl即使我指定 openjpa同时安装的功能。我发现可以通过更改 effective:=active 来解决此问题至resolution:=optional

为了构建我的包，我尝试了以下 Maven 插件配置:

<plugin>
    <groupId>org.apache.felix</groupId>
    <artifactId>maven-bundle-plugin</artifactId>
    <version>3.3.0</version>
    <extensions>true</extensions>
    <configuration>
        <instructions>
            <Export-Package>com.example
            </Export-Package>
            <Include-Resource>
                        META-INF/persistence.xml=${project.build.directory}/classes/META-INF/persistence.xml,
                        {maven-resources}
            </Include-Resource>
            <Meta-Persistence>META-INF/persistence.xml</Meta-Persistence>
            <Require-Capability>
                        osgi.service;resolution:=optional;objectClass=javax.persistence.spi.PersistenceProvider;javax.persistence.provider=org.apache.openjpa.persistence.PersistenceProviderImpl,
                        osgi.extender;resolution:=optional;osgi.extender=aries.jpa,
                        osgi.service;resolution:=optional;objectClass=javax.sql.DataSource;filter:="(osgi.jndi.service.name=jdbc/test)"
            </Require-Capability>
        </instructions>
    </configuration>
</plugin>

但是，我遇到了与上面链接的问题相同的问题，即 list 中的重复要求。

我还从上述问题的链接中看到，对 bnd 进行了更改(bnd 问题 #1364)，但这似乎只适用于注释？有没有办法配置 Maven 插件来防止重复的需求？

更新#1

我的示例代码可在 GitHub(karaf_features 分支)获取: https://github.com/jtkb/jpatest/tree/feature/karaf_features

它由 3 个模块组成，但只有 2 个模块对此问题感兴趣，simple和simple-datasource

simple是“持久性单元”并包含 persistence.xml 。它也是其中“尴尬”(但真正的要求)<Require-Capability>的 bundle 。生成 header 。

simple-datasource向持久性单元提供数据源并包含要安装的 Karaf 功能 simple , simple-datasource bundle 和所有必需的第 3 方 bundle (通过 Karaf 功能)。特征 XML 包含:

<feature name="simple-datasource" description="simple-datasource" version="1.0.0.SNAPSHOT">
    <feature version="4.1.1">jdbc</feature>
    <feature version="2.6.0">jpa</feature>
    <feature version="2.4.1">openjpa</feature>
    <feature version="1.0.1">pax-jdbc-mariadb</feature>
    <bundle>mvn:com.javatechnics.jpa/simple-datasource/1.0.0-SNAPSHOT</bundle>
    <bundle>mvn:com.javatechnics.jpa/simple/1.0.0-SNAPSHOT</bundle>
</feature>

因此在 Karaf 中安装我的功能时出现此错误:

Error executing command: Unable to resolve root: missing requirement [root] osgi.identity; osgi.identity=simple-datasource; type=karaf.feature; version="[1.0.0.SNAPSHOT,1.0.0.SNAPSHOT]"; filter:="(&(osgi.identity=simple-datasource)(type=karaf.feature)(version>=1.0.0.SNAPSHOT)(version<=1.0.0.SNAPSHOT))"

[caused by: Unable to resolve simple-datasource/1.0.0.SNAPSHOT: missing requirement [simple-datasource/1.0.0.SNAPSHOT] osgi.identity; osgi.identity=com.javatechnics.jpa.simple; type=osgi.bundle; version="[1.0.0.SNAPSHOT,1.0.0.SNAPSHOT]"; resolution:=mandatory

[caused by: Unable to resolve com.javatechnics.jpa.simple/1.0.0.SNAPSHOT: missing requirement [com.javatechnics.jpa.simple/1.0.0.SNAPSHOT] osgi.service; objectClass=javax.persistence.spi.PersistenceProvider; javax.persistence.provider=org.apache.openjpa.persistence.PersistenceProviderImpl; effective:=active]]

对我来说，这个错误几乎感觉像是一个循环引用问题，但我不明白是怎么回事。

检查 simple 的 header 捆绑:

simple (59)
-----------
Bnd-LastModified = 1513115007378
Build-Jdk = 1.8.0_144
Built-By = kerry
Created-By = Apache Maven Bundle Plugin
Manifest-Version = 1.0
Meta-Persistence = META-INF/persistence.xml
Tool = Bnd-3.2.0.201605172007

Bundle-Blueprint = OSGI-INF/blueprint/blueprint.xml
Bundle-ManifestVersion = 2
Bundle-Name = simple
Bundle-SymbolicName = com.javatechnics.jpa.simple
Bundle-Version = 1.0.0.SNAPSHOT

Export-Service = 
com.javatechnics.jpa.dao.BookServiceDao;ServiceManager=Blueprint;name=
BookServiceDao
Provide-Capability = 
osgi.service;effective:=active;objectClass=javax.persistence.EntityManagerFactory;osgi.unit.name=test,
osgi.service;effective:=active;objectClass=org.apache.aries.jpa.template.JpaTemplate;osgi.unit.name=test,
osgi.service;effective:=active;objectClass=javax.persistence.EntityManager;osgi.unit.name=test,
osgi.service;effective:=active;objectClass=org.apache.aries.jpa.supplier.EmSupplier;osgi.unit.name=test
Require-Capability = 
osgi.service;effective:=active;javax.persistence.provider=org.apache.openjpa.persistence.PersistenceProviderImpl;objectClass=javax.persistence.spi.PersistenceProvider,
osgi.extender;osgi.extender=aries.jpa,
 osgi.service;effective:=active;filter:=(osgi.jndi.service.name=jdbc/test);objectClass=javax.sql.DataSource,
osgi.ee;filter:=(&(osgi.ee=JavaSE)(version=1.5))

Export-Package = 
com.javatechnics.jpa;uses:="com.javatechnics.jpa.dao,javax.persistence";version=1.0.0,
com.javatechnics.jpa.dao;uses:=com.javatechnics.jpa;version=1.0.0
Import-Package = 
com.javatechnics.jpa,
com.javatechnics.jpa.dao,
javax.persistence;version="[1.1,2)",
org.osgi.service.blueprint;version="[1.0.0,2.0.0)"

Answer 1

如果您知道一个 bundle (我们称之为xyz)提供了PersistenceProvider服务，那么您可以编写一个额外的 bundle 来简单地执行以下操作:这个:

Require-Bundle: xyz; bundle-version="[...)"
Provide-Capability: osgi.service;
    objectClass=javax.persistence.spi.PersistenceProvider;
    javax.persistence.provider=org.apache.openjpa.persistence.PersistenceProviderImpl;
    effective:=active

这本质上增强了 bundle xyz 的能力，可以解决 bundle 中的需求，但代价是添加一个无用的 bundle 。

这仍然是一种解决方法，但比从 bundle 中删除实际需求要好。