fedora.server.access.dissemination
Class DisseminationService

java.lang.Object
  fedora.server.access.dissemination.DisseminationService

public class DisseminationService
extends java.lang.Object

Title: DisseminationService.java

Description: A service for executing a dissemination given its binding information.

Version:

$Id: DisseminationService.java 6244 2007-10-31 18:54:34Z rwayland3 $

Author:

rlw@virginia.edu

Field Summary

protected static java.util.Hashtable	beSecurityHash
protected static java.util.Hashtable	dsRegistry The hashtable containing information required for datastream mediation.

Constructor Summary

DisseminationService()
Constructs an instance of DisseminationService.

Method Summary

MIMETypedStream	assembleDissemination(Context context, java.lang.String PID, java.util.Hashtable h_userParms, DisseminationBindingInfo[] dissBindInfoArray, java.lang.String bMechPid, java.lang.String methodName) Assembles a dissemination given an instance of DisseminationBindingInfo which has the dissemination-related information from the digital object and its associated Behavior Mechanism object.
java.lang.String	extractTimestamp(java.lang.String tempID) The tempID that is used for datastream mediation consists of a Timestamp plus a counter appended to the end to insure uniqueness.
MIMETypedStream	getDisseminationContent(java.lang.String url, Context context, java.lang.String user, java.lang.String pass) A method that reads the contents of the specified URL and returns the result as a MIMETypedStream
static void	printBindingInfo(DisseminationBindingInfo[] info)
java.lang.String	registerDatastreamLocation(java.lang.String dsLocation, java.lang.String dsControlGroupType, java.lang.String beServiceCallbackRole, java.lang.String methodName) Datastream locations are considered privileged information by the Fedora repository.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

dsRegistry

protected static java.util.Hashtable dsRegistry

The hashtable containing information required for datastream mediation.

beSecurityHash

protected static java.util.Hashtable beSecurityHash

Constructor Detail

DisseminationService

public DisseminationService()

Constructs an instance of DisseminationService. Initializes two class variables that contain the IP address and port number of the Fedora server. The port number is obtained from the Fedora server config file and the IP address of the server is obtained dynamically. These variables are needed to perform the datastream proxy service for datastream requests.

Method Detail

assembleDissemination

public MIMETypedStream assembleDissemination(Context context,
                                             java.lang.String PID,
                                             java.util.Hashtable h_userParms,
                                             DisseminationBindingInfo[] dissBindInfoArray,
                                             java.lang.String bMechPid,
                                             java.lang.String methodName)
                                      throws ServerException

Assembles a dissemination given an instance of DisseminationBindingInfo which has the dissemination-related information from the digital object and its associated Behavior Mechanism object.

Parameters:

context - The current context.

PID - The persistent identifier of the digital object.

h_userParms - A hashtable of user-supplied method parameters.

dissBindInfoArray - The associated dissemination binding information.

Returns:

A MIME-typed stream containing the result of the dissemination.

Throws:

ServerException - If unable to assemble the dissemination for any reason.

registerDatastreamLocation

public java.lang.String registerDatastreamLocation(java.lang.String dsLocation,
                                                   java.lang.String dsControlGroupType,
                                                   java.lang.String beServiceCallbackRole,
                                                   java.lang.String methodName)
                                            throws ServerException

Datastream locations are considered privileged information by the Fedora repository. To prevent disclosing physical datastream locations to external mechanism services, a proxy is used to disguise the datastream locations. This method generates a temporary ID that maps to the physical datastream location and registers this information in a memory resident hashtable for subsequent resolution of the physical datastream location. The servlet DatastreamResolverServlet provides the proxy resolution service for datastreams.

The format of the tempID is derived from java.sql.Timestamp with an arbitrary counter appended to the end to insure uniqueness. The syntax is of the form:

YYYY-MM-DD HH:mm:ss.mmm:dddddd where

• YYYY - year (1900-8099)
• MM - month (01-12)
• DD - day (01-31)
• hh - hours (0-23)
• mm - minutes (0-59)
• ss - seconds (0-59)
• mmm - milliseconds (0-999)
• dddddd - incremental counter (0-999999)

Parameters:

dsLocation - The physical location of the datastream.

dsControlGroupType - The type of the datastream.

Returns:

A temporary ID used to reference the physical location of the specified datastream

Throws:

ServerException - If an error occurs in registering a datastream location.

extractTimestamp

public java.lang.String extractTimestamp(java.lang.String tempID)

The tempID that is used for datastream mediation consists of a Timestamp plus a counter appended to the end to insure uniqueness. This method is a utility method used to extract the Timestamp portion from the tempID by stripping off the arbitrary counter at the end of the string.

Parameters:

tempID - The tempID to be extracted.

Returns:

The extracted Timestamp value as a string.

printBindingInfo

public static void printBindingInfo(DisseminationBindingInfo[] info)

getDisseminationContent

public MIMETypedStream getDisseminationContent(java.lang.String url,
                                               Context context,
                                               java.lang.String user,
                                               java.lang.String pass)
                                        throws GeneralException,
                                               HttpServiceNotFoundException

A method that reads the contents of the specified URL and returns the result as a MIMETypedStream

Parameters:

url - The URL of the external content.

Returns:

A MIME-typed stream.

Throws:

HttpServiceNotFoundException - If the URL connection could not be established.

GeneralException