Package org.datanucleus.plugin
Interface PluginRegistry
- All Known Implementing Classes:
NonManagedPluginRegistry
,OSGiPluginRegistry
public interface PluginRegistry
Loader and registry of Extensions and Extension Points.
The implementation of this interface must have a public constructor taking the ClassLoaderResolver interface as argument.
The plugin registry metadata/bundle resolution is ruled by OSGi specification.
The following sections of the OSGi 3.0 specification must be fully supported: 3.5.2, 3.5.3, 3.2.4, 3.2.5.
The section 3.6.3 is optional. All other OSGi parts not mentioned above are not likely to be supported.
See https://dzone.com/articles/extensionserviceplugin-mechanisms-in-java for a comparison of some different plugin mechanisms in Java. The one we use is based around Eclipse extensions/extension points.
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Method Summary
Modifier and TypeMethodDescriptioncreateExecutableExtension
(ConfigurationElement confElm, String name, Class[] argTypes, Object[] args) Loads a class (do not initialize) from an attribute ofConfigurationElement
Bundle[]
Accessor for all registered bundlesAcessor for the ExtensionPointAcessor for the currently registed ExtensionPointsLoads a class (do not initialize)void
Look for Bundles/Plugins and register them.void
Look for Bundles/Plugins and register them.void
Resolve constraints declared in bundle manifest.mf files.resolveURLAsFileURL
(URL url) Converts a URL that uses a user-defined protocol into a URL that uses the file protocol.
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Method Details
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getExtensionPoint
Acessor for the ExtensionPoint- Parameters:
id
- the unique id of the extension point- Returns:
- null if the ExtensionPoint is not registered
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getExtensionPoints
ExtensionPoint[] getExtensionPoints()Acessor for the currently registed ExtensionPoints- Returns:
- array of ExtensionPoints
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registerExtensionPoints
void registerExtensionPoints()Look for Bundles/Plugins and register them. Register also ExtensionPoints and Extensions declared in /plugin.xml files -
registerExtensions
void registerExtensions()Look for Bundles/Plugins and register them. Register also ExtensionPoints and Extensions declared in /plugin.xml files -
createExecutableExtension
Object createExecutableExtension(ConfigurationElement confElm, String name, Class[] argTypes, Object[] args) throws ClassNotFoundException, SecurityException Loads a class (do not initialize) from an attribute ofConfigurationElement
- Parameters:
confElm
- the configuration elementname
- the attribute nameargTypes
- Types of the constructor argumentsargs
- The arguments- Returns:
- the instance
- Throws:
ClassNotFoundException
- If an error occursSecurityException
- If an error occurs
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loadClass
Loads a class (do not initialize)- Parameters:
pluginId
- the plugin idclassName
- the class name- Returns:
- the Class
- Throws:
ClassNotFoundException
- if an error occurs in loading
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resolveURLAsFileURL
Converts a URL that uses a user-defined protocol into a URL that uses the file protocol.- Parameters:
url
- the url to be converted- Returns:
- the converted URL
- Throws:
IOException
- if an error occurs
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resolveConstraints
void resolveConstraints()Resolve constraints declared in bundle manifest.mf files. This must be invoked after registering all bundles. Should log errors if bundles are not resolvable, or raise runtime exceptions. -
getBundles
Bundle[] getBundles()Accessor for all registered bundles- Returns:
- the bundles
- Throws:
UnsupportedOperationException
- if this operation is not supported by the implementation
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