Package javax.faces

Class FactoryFinder


  • public final class FactoryFinder
extends java.lang.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 injectionProvider 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 injectionProvider 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 injectionProvider 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.

    • Method Detail

      • getFactory

        public static java.lang.Object getFactory​(java.lang.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.

        The standard injectionProvider and wrappers in JSF all implement the interface FacesWrapper. If the returned Object is an implementation of one of the standard injectionProvider, it must be legal to cast it to an instance of FacesWrapper and call FacesWrapper.getWrapped() on the instance.

        Parameters:
        factoryName - Fully qualified name of the JavaServer Faces factory for which an implementation instance is requested
        Returns:
        the found factory instance
        Throws:
        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
        java.lang.IllegalArgumentException - if factoryName does not identify a standard JavaServer Faces factory name
        java.lang.IllegalStateException - if there is no configured factory implementation class for the specified factory name
        java.lang.NullPointerException - if factoryname is null

      • setFactory

        public static void setFactory​(java.lang.String factoryName,
                              java.lang.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

        Parameters:
        factoryName - the name to be used in a subsequent call to getFactory(java.lang.String).
        implName - the fully qualified class name of the factory corresponding to factoryName.
        Throws:
        java.lang.IllegalArgumentException - if factoryName does not identify a standard JavaServer Faces factory name
        java.lang.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 must be called during of web application shutdown.

        Throws:
        FacesException - if the web application class loader cannot be identified