jpa.p1.pub
Class Publisher

java.lang.Object
  |
  +--jpa.p1.pub.Publisher

public class Publisher

extends java.lang.Object

This is the main class in the JPA PlatformOne Publishing package, which is used for subscribing to PlatformOne data. All the other classes are accessed through this one.

The JPA PlatformOne Publishing package, jpa.p1.pub, is implemented as a hierarchical set of pairs of classes and interfaces.

There are five fundamental levels of class in this package:

Publisher
PubDatasetList
PubDataset
PubRecord
PubUpdate

For each of these levels (with the exception of PubRecord), there is one class that is implemented by the package (Pubxxx) itself and an interface that can be implemented by the application (PubxxxEvent). The latter interface us used to receive asynchronous events from the package. An application always starts by instantiating a Publisher object, passing it in a reference to an application object that implements the PublisherEvent interface. From this point on, the order of instantiation is dependent on the nature of the application.

There are also a couple of classes that are used to access other aspects of the incoming data. These are as follows:

PubSchema
PubField


Constructor Summary

Publisher(PublisherEvent event)
This is the sole constructor for Publisher.

Method Summary

void	addHost(java.lang.String address, int port) This method adds a PlatformOne server to the list of alternatives for making a connection to.
void	clearHosts() This method clears the list of alternative PlatformOne server hosts.
boolean	connect() This method attempts to establish a connection to the first available server host.
boolean	connectToHost(java.lang.String address, int port) This method attempts to establish a connection to the specified PlatformOne server host.
void	disconnect() This method disconnects from the current PlatformOne server host, or abandons connection attempts if there is currently no connection.
PubDataset	getDataset(java.lang.String name) This method gets a reference to an object representing a dataset.
PubDatasetList	getDatasetList() This method gets a reference to the object representing the dataset list.
java.lang.String	getUser() This method gets the current user name.

Methods inherited from class java.lang.Object

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

Constructor Detail

Publisher

public Publisher(PublisherEvent event)

This is the sole constructor for Publisher. The single argument is a reference to an object in the application that implements the PublisherEvent interface. This is used to catch events related to the state of the connection to PlatformOne.

Method Detail

addHost

public void addHost(java.lang.String address,
                    int port)

This method adds a PlatformOne server to the list of alternatives for making a connection to.

connect

public boolean connect()

This method attempts to establish a connection to the first available server host. If the attempt fails, the client application will try the other hosts in turn, until the alternatives are exhausted. It will then wait a timeout period before trying again. This interval is initially 15 seconds, and then whatever centralised value is returned by the first successful connection.

disconnect

public void disconnect()

This method disconnects from the current PlatformOne server host, or abandons connection attempts if there is currently no connection.

connectToHost

public boolean connectToHost(java.lang.String address,
                             int port)

This method attempts to establish a connection to the specified PlatformOne server host. This is equivalent to invoking clearHosts, followed by addHost and then connect.

clearHosts

public void clearHosts()

This method clears the list of alternative PlatformOne server hosts.

getDatasetList

public PubDatasetList getDatasetList()

This method gets a reference to the object representing the dataset list.

getDataset

public PubDataset getDataset(java.lang.String name)

This method gets a reference to an object representing a dataset. If the client is currently connected to a PlatformOne host, and this host can accept publications to this dataset, the object will be populated. Normally, it is recommended that a client should watch the dataset, and wait to be told that it is ready before attempting to publish data.

getUser

public java.lang.String getUser()

This method gets the current user name.