Class MarshallerPool


  • public class MarshallerPool
    extends Object
    Creates and configures Marshaller or Unmarshaller objects for use with SIS. Users fetch (un)marshallers by calls to the acquire­Marshaller() or acquire­Unmarshaller() methods, and can restitute the (un)marshaller to the pool after usage like below:
    Marshaller marshaller = pool.acquireMarshaller();
    marshaller.marchall(...);
    pool.recycle(marshaller);
    Configuring (un)marshallers
    The (un)marshallers created by this class can optionally by configured with the SIS-specific properties defined in the XML class, in addition to JAXB standard properties.
    Thread safety
    The same Marshaller­Pool instance can be safely used by many threads without synchronization on the part of the caller. Subclasses should make sure that any overridden methods remain safe to call from multiple threads.
    Since:
    0.3
    See Also:
    XML, JAXB Performance and thread-safety

    Defined in the sis-metadata module

    • Constructor Detail

      • MarshallerPool

        public MarshallerPool​(Map<String,​?> properties)
                       throws JAXBException
        Creates a new factory using the SIS default JAXBContext instance. The properties map is optional. If non-null, then the keys can be XML constants or the names of any other properties recognized by both Marshaller and Unmarshaller implementations.

        Tip: if the properties for the Marshaller differ from the properties for the Unmarshaller, then consider overriding the create­Marshaller() or create­Unmarshaller() methods instead.

        Parameters:
        properties - the properties to be given to the (un)marshaller, or null if none.
        Throws:
        JAXBException - if the JAXB context can not be created.
      • MarshallerPool

        public MarshallerPool​(JAXBContext context,
                              Map<String,​?> properties)
                       throws JAXBException
        Creates a new factory using the given JAXB context. The properties map is optional. If non-null, then the keys can be XML constants or the names of any other properties recognized by both Marshaller and Unmarshaller implementations.

        Tip: if the properties for the Marshaller differ from the properties for the Unmarshaller, then consider overriding the create­Marshaller() or create­Unmarshaller() methods instead.

        Parameters:
        context - the JAXB context.
        properties - the properties to be given to the (un)marshaller, or null if none.
        Throws:
        JAXBException - if the marshaller pool can not be created.
    • Method Detail

      • acquireMarshaller

        public Marshaller acquireMarshaller()
                                     throws JAXBException
        Returns a JAXB marshaller from the pool. If there is no marshaller currently available in the pool, then this method will create a new one.

        This method shall be used as below:

        Marshaller marshaller = pool.acquireMarshaller();
        marshaller.marchall(...);
        pool.recycle(marshaller);
        Note that recycle(Marshaller) shall not be invoked in case of exception, since the marshaller may be in an invalid state.
        Returns:
        a marshaller configured for formatting OGC/ISO XML.
        Throws:
        JAXBException - if an error occurred while creating and configuring a marshaller.
      • acquireUnmarshaller

        public Unmarshaller acquireUnmarshaller()
                                         throws JAXBException
        Returns a JAXB unmarshaller from the pool. If there is no unmarshaller currently available in the pool, then this method will create a new one.

        This method shall be used as below:

        Unmarshaller unmarshaller = pool.acquireUnmarshaller();
        Unmarshaller.unmarchall(...);
        pool.recycle(unmarshaller);
        Note that recycle(Unmarshaller) shall not be invoked in case of exception, since the unmarshaller may be in an invalid state.
        Returns:
        a unmarshaller configured for parsing OGC/ISO XML.
        Throws:
        JAXBException - if an error occurred while creating and configuring the unmarshaller.
      • recycle

        public void recycle​(Marshaller marshaller)
        Declares a marshaller as available for reuse. The caller should not use anymore the given marshaller after this method call, since the marshaller may be re-used by another thread at any time after recycle.
        Cautions
        • Do not invoke this method if the marshaller threw an exception, since the marshaller may be in an invalid state. In particular, this method should not be invoked in a finally block.
        • Do not invoke this method twice for the same marshaller, unless the marshaller has been obtained by a new call to acquire­Marshaller(). In case of doubt, it is better to not recycle the marshaller at all.
        Note that this method does not close any output stream. Closing the marshaller stream is caller's or JAXB responsibility.
        Parameters:
        marshaller - the marshaller to return to the pool.
      • recycle

        public void recycle​(Unmarshaller unmarshaller)
        Declares a unmarshaller as available for reuse. The caller should not use anymore the given unmarshaller after this method call, since the unmarshaller may be re-used by another thread at any time after recycle.
        Cautions
        • Do not invoke this method if the unmarshaller threw an exception, since the unmarshaller may be in an invalid state. In particular, this method should not be invoked in a finally block.
        • Do not invoke this method twice for the same unmarshaller, unless the unmarshaller has been obtained by a new call to acquire­Unmarshaller(). In case of doubt, it is better to not recycle the unmarshaller at all.
        Note that this method does not close any input stream. Closing the unmarshaller stream is caller's or JAXB responsibility.
        Parameters:
        unmarshaller - the unmarshaller to return to the pool.
      • createMarshaller

        protected Marshaller createMarshaller()
                                       throws JAXBException
        Creates an configures a new JAXB marshaller. This method is invoked only when no existing marshaller is available in the pool. Subclasses can override this method if they need to change the marshaller configuration.
        Returns:
        a new marshaller configured for formatting OGC/ISO XML.
        Throws:
        JAXBException - if an error occurred while creating and configuring the marshaller.
        See Also:
        context, acquire­Marshaller()
      • createUnmarshaller

        protected Unmarshaller createUnmarshaller()
                                           throws JAXBException
        Creates an configures a new JAXB unmarshaller. This method is invoked only when no existing unmarshaller is available in the pool. Subclasses can override this method if they need to change the unmarshaller configuration.
        Returns:
        a new unmarshaller configured for parsing OGC/ISO XML.
        Throws:
        JAXBException - if an error occurred while creating and configuring the unmarshaller.
        See Also:
        context, acquire­Unmarshaller()