FactoryFinder (Java EE 5 SDK)

javax.faces Class FactoryFinder

java.lang.Object
  javax.faces.FactoryFinder

public final class FactoryFinder

extends Object

FactoryFinder implements the standard discovery algorithm for all factory objects specified in the JavaServer Faces APIs. For a given factory class name, a corresponding implementation class is searched for based on the following algorithm. Items are listed in order of decreasing search precedence:

• If the JavaServer Faces configuration file bundled into the WEB-INF directory of the webapp contains a factory entry of the given factory class name, that factory is used.
• If the JavaServer Faces configuration files named by the javax.faces.CONFIG_FILES ServletContext init parameter contain any factory entries of the given factory class name, those factories are used, with the last one taking precedence.
• If there are any JavaServer Faces configuration files bundled into the META-INF directory of any jars on the ServletContext's resource paths, the factory entries of the given factory class name in those files are used, with the last one taking precedence.
• If a META-INF/services/{factory-class-name} resource is visible to the web application class loader for the calling application (typically as a result of being present in the manifest of a JAR file), its first line is read and assumed to be the name of the factory implementation class to use.
• If none of the above steps yield a match, the JavaServer Faces implementation specific class is used.

If any of the factories found on any of the steps above happen to have a one-argument constructor, with argument the type being the abstract factory class, that constructor is invoked, and the previous match is passed to the constructor. For example, say the container vendor provided an implementation of FacesContextFactory, and identified it in META-INF/services/javax.faces.context.FacesContextFactory in a jar on the webapp ClassLoader. Also say this implementation provided by the container vendor had a one argument constructor that took a FacesContextFactory instance. The FactoryFinder system would call that one-argument constructor, passing the implementation of FacesContextFactory provided by the JavaServer Faces implementation.

If a Factory implementation does not provide a proper one-argument constructor, it must provide a zero-arguments constructor in order to be successfully instantiated.

Once the name of the factory implementation class is located, the web application class loader for the calling application is requested to load this class, and a corresponding instance of the class will be created. A side effect of this rule is that each web application will receive its own instance of each factory class, whether the JavaServer Faces implementation is included within the web application or is made visible through the container's facilities for shared libraries.

APPLICATION_FACTORY

public static final String APPLICATION_FACTORY

The property name for the ApplicationFactory class name.

另请参见:

常量字段

FACES_CONTEXT_FACTORY

public static final String FACES_CONTEXT_FACTORY

The property name for the FacesContextFactory class name.

另请参见:

常量字段

LIFECYCLE_FACTORY

public static final String LIFECYCLE_FACTORY

The property name for the LifecycleFactory class name.

另请参见:

常量字段

RENDER_KIT_FACTORY

public static final String RENDER_KIT_FACTORY

The property name for the RenderKitFactory class name.

另请参见:

常量字段

getFactory

public static Object getFactory(String factoryName)
                         throws FacesException

Create (if necessary) and return a per-web-application instance of the appropriate implementation class for the specified JavaServer Faces factory class, based on the discovery algorithm described in the class description.

参数:

factoryName - Fully qualified name of the JavaServer Faces factory for which an implementation instance is requested

抛出异常:

FacesException - if the web application class loader cannot be identified

FacesException - if an instance of the configured factory implementation class cannot be loaded

FacesException - if an instance of the configured factory implementation class cannot be instantiated

IllegalArgumentException - if factoryName does not identify a standard JavaServer Faces factory name

IllegalStateException - if there is no configured factory implementation class for the specified factory name

NullPointerException - if factoryname is null

setFactory

public static void setFactory(String factoryName,
                              String implName)

This method will store the argument factoryName/implName mapping in such a way that getFactory(java.lang.String) will find this mapping when searching for a match.

This method has no effect if getFactory() has already been called looking for a factory for this factoryName.

This method can be used by implementations to store a factory mapping while parsing the Faces configuration file

抛出异常:

IllegalArgumentException - if factoryName does not identify a standard JavaServer Faces factory name

NullPointerException - if factoryname is null

releaseFactories

public static void releaseFactories()
                             throws FacesException

Release any references to factory instances associated with the class loader for the calling web application. This method should be called as apart of web application shutdown in a container where the JavaServer Faces API classes are part of the container itself, rather than being included inside the web application.

抛出异常:

FacesException - if the web application class loader cannot be identified

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