org.dvb.dsmcc.ServiceDomain Maven / Gradle / Ivy
package org.dvb.dsmcc;
import java.io.*;
import org.davic.net.*;
/**
* A ServiceDomain represents a group of DSMCC objects. The objects
* are sent either using the object carousel for a broadcast network or with
* the DSM-CC User-to-User protocol for an interactive network.
*
* To access the objects of a ServiceDomain, it has to be attached to the
* file system name space of the MHP terminal.
*
* To access the content of an object, the application has four ways:
*
* - It can instantiate the class that is used to read the object
* (java.io.FileInputStream or java.io.RandomAccessFile for a File
* or DSMCCStream for a stream) from its pathname.
* The loading of the object is implicit but the application has
* no way to abort it.
* NB: Obviously, for the Object Carousel, the write mode of
* java.io.RandomAccessFile is not allowed.
*
- It can instantiate a DSMCCObject and carry out a
* Synchronous loading. The loading can be aborted by the abort method
* of the DSMCCObject class.
* When the object is loaded, the application will instantiate the
* class used to read the object.
*
- It can instantiate a DSMCCObject and carry out an Asynchronous
* loading. So several loading can be started in parallel from the
* same thread.
*
- It is also possible to create directly a java.io.File for a DSMCC
* object.
*
* Instances of ServiceDomain exist in two states, attached and
* detached. Newly created instances are always in the detached state. They
* become attached when a call to the attach method succeeds.
* They become detached following a call to the detach method.
* When service domains in the attached state temporarily lose their network connection (e.g.
* if the MHP terminal tunes away from the transport stream
* where they are carried),
* the behaviour of DSMCC objects which are part of the
* service domain is specified in the main body of the present document. If such
* a network connection becomes available again then the service domain shall
* resume normal behaviour.
* A service domain which is temporarily lost its network connection may be
* forced into the detached state by the implementation if the loss of the
* network connection becomes irrecoverable. The precise details of when this
* happens are implementation dependent. This is the only situation when
* shall be forced into the detached state. Once a ServiceDomain is detached,
* it will never be automatically attached.
*/
public class ServiceDomain {
/**
* Creates a ServiceDomain object.
*/
public ServiceDomain() {
}
/**
* This function is used to attach a ServiceDomain from an object carousel.
* It loads the module which contains the service gateway object and
* mounts the ServiceDomain volume in the file system hierarchy.
* This call will block until the service gateway is loaded.
* It can be aborted by another thread with the method detach. In this case an
* InterruptedIOException is thrown.
*
*
Calling this method on a ServiceDomain object already in the attached
* state shall imply a detach of the ServiceDomain object before the attach
* operation unless the ServiceDomain is already attached to the correct location.
* Hence if the attach operation fails, the appropriate exception for the failure mode shall
* be thrown and the ServiceDomain is left in a detached state and not attached
* to the former object carousel / service domain. If the ServiceDomain is
* already attached to the correct location then the method call shall have no effect.
* @param aDVBService The coordinates of the DVB service which contains the
* object carousel. This locator has to point to a DVB service.
* @param aCarouselId The identifier of the carousel.
* @exception InterruptedIOException The attachment has been aborted.
* @exception MPEGDeliveryException An MPEG error occurred (such as time-out).
* @exception ServiceXFRException The service gateway cannot be loaded in the current service domain.
* This exception shall not be thrown in this version of the specification.
*/
public void attach(org.davic.net.Locator aDVBService, int aCarouselId)
throws ServiceXFRException, InterruptedIOException, MPEGDeliveryException {
}
/**
* This function is used to attach a ServiceDomain from an object carousel.
* It loads the module which contains the service gateway object and
* mounts the ServiceDomain volume in the file system hierarchy.
* This call will block until the service gateway is loaded. It can be
* aborted by another thread with the method detach. In this case an
* InterruptedIOException is thrown.
*
Calling this method on a ServiceDomain object already in the attached
* state shall imply a detach of the ServiceDomain object before the attach
* operation unless the ServiceDomain is already attached to the correct location.
* Hence if the attach operation fails, the appropriate exception for the failure mode shall
* be thrown and the ServiceDomain is left in a detached state and not attached
* to the former object carousel / service domain. If the ServiceDomain is
* already attached to the correct location then the method call shall have no effect.
*
* @param l The locator pointing to the elementary stream carrying the DSI
* of the object carousel, or to a DVB service that carries one and only
* one object carousel.
*
* @exception DSMCCException An error has occurred during the attachment. For
* example, the locator does not point to a component carrying a DSI
* of an Object Carousel or to a service containing a single carousel
* @exception InterruptedIOException The attachment has been aborted.
* @exception MPEGDeliveryException attaching to this domain would require tuning.
*
*/
public void attach (org.davic.net.Locator l)
throws DSMCCException, InterruptedIOException, MPEGDeliveryException {
}
/**
* This function is used to attach a ServiceDomain from either
* an object carousel or from an interactive network.
* This call will block until the attachment is done.
*
Calling this method on a ServiceDomain object already in the attached
* state shall imply a detach of the ServiceDomain object before the attach
* operation unless the ServiceDomain is already attached to the correct location.
* Hence if the attach operation fails, the appropriate exception for the failure mode shall
* be thrown and the ServiceDomain is left in a detached state and not attached
* to the former object carousel / service domain. If the ServiceDomain is
* already attached to the correct location then the method call shall have no effect.
*
* @param NSAPAddress The NSAP Address of a ServiceDomain as defined in
* in ISO/IEC 13818-6
* @exception InterruptedIOException The attachment has been aborted.
* @exception InvalidAddressException The NSAP Address is invalid.
* @exception DSMCCException An error has occurred during the attachment.
* @exception MPEGDeliveryException attaching to this domain would require tuning.
*/
public void attach(byte[] NSAPAddress)
throws DSMCCException, InterruptedIOException,
InvalidAddressException, MPEGDeliveryException {
}
/**
* A call to this method is a hint that the applications gives to the
* MHP to unmount the volume and delete the objects of the service
* domain. When another application is using objects of the same
* service domain the method has no effects. When there are no other
* application using objects of the service domain, a call to this
* method is a hint that the MHP can free all the resources allocated to
* this service domain.
* After this, the ServiceDomain will be in a non-attached state and will behave
* as if it had just been constructed. Subsequent calls to detach
* shall throw NotLoadedException.
* @exception NotLoadedException is thrown if the ServiceDomain
* is not attached or if there is no call to attach in progress.
*/
public void detach() throws NotLoadedException {
}
/**
* This method returns the NSAP address of the ServiceDomain.
*
* @return the NSAP address of the ServiceDomain.
* @exception NotLoadedException is thrown if the ServiceDomain
* is not attached.
*/
public byte[] getNSAPAddress() throws NotLoadedException {
return null;
}
/**
* Obtain a java.net.URL corresponding to a 'dvb:' locator.
* If the service domain corresponding to the locator is attached
* and the file referenced in the locator exists then an instance of
* java.net.URL is returned which can be used to reference
* this file.
*
* @param l a locator object encapsulating a 'dvb:' locator which
* includes a 'dvb_abs_path' element.
* @return a java.net.URL which can be used to access the
* file referenced by the 'dvb:' locator
* @exception InvalidLocatorException if the locator is not a valid 'dvb:'
* locator or does not includes all elements including 'dvb_abs_path' element
* @exception NotLoadedException is thrown if the locator is valid and includes
* enough information but it references a service domain which is not attached.
* @exception FileNotFoundException if the service domain is attached
* but the file referenced by the locator does not exist
*/
public static java.net.URL getURL( org.davic.net.Locator l) throws
NotLoadedException, InvalidLocatorException, FileNotFoundException
{ return null; }
/**
* Returns a DSMCCObject object describing the top level directory
* of this ServiceDomain. If the ServiceDomain object is not attached
* then null is returned.
*
* @return an instance of org.dvb.dsmcc.DSMCCObject if attached or null otherwise
*
* @since MHP 1.0.1
*/
public DSMCCObject getMountPoint() { return null;}
/**
* Return whether the network connection for this service domain is available.
* This return value is independent of whether the service domain is attached
* or not. If a service domain is distributed across multiple network connections
* (e.g. using the optional support for DSMCC over IIOP) then this will reflect
* the availability of the network connection carrying the object mounted to the
* mount point.
*
* @return true if the network connection for this service domain is available otherwise false
* @since MHP 1.0.1
*/
public boolean isNetworkConnectionAvailable() { return false; }
/**
* Return whether this service domain is in the attached or detached state.
* @return true if this service domain is in the attached state, otherwise false
* @since MHP 1.0.1
*/
public boolean isAttached() { return false ;}
/**
* Return the locator for this service domain.
* If this ServiceDomain instance was last attached by specifying a locator
* then an equivalent locator shall be returned except if the original locator
* contained extra information that is not necessary to identify the service domain
* in which case this extra information is removed.
* If the attach was done with the attach(locator, int)
* signature, the locator is complemented with the component_tag value that the
* platform has identified during attaching the ServiceDomain.
* If this ServiceDomain instance was last attached by specifying
* an NSAP address then the locator shall be generated from that address. If
* this ServiceDomain has never been attached then null shall be returned.
* The syntax of the NSAP address is defined in section titled "LiteOptionsProfileBody"
* in annex B of the MHP specification. It contains the same fields as the locator
* syntax specified in the System integration aspects clause. The locator is
* constructed by taking the fields out of the NSAP address and encoding them in the
* locator syntax together with the component_tag value that the platform has identified
* during attaching the ServiceDomain.
* @since MHP 1.0.1
*
* @return a locator for this service domain
*/
public Locator getLocator() { return null; }
}