wan

GemStone^® GemFire^TM Enterprise

WAN Example

The wan example is an application that simulates two WAN sites, namely a US Site and an EU Site. The example is located in the GemFire installation under examples/dist/wan.

The WAN example contains the following four components:

• A US WAN Client that puts entries into a WAN-enabled region
• A US WAN Hub that receives those entries and distributes them to the EU WAN Hub
• An EU WAN Hub that receives the distributed WAN events from the US Hub and distributes them to its clients
• An EU WAN Client that receives the WAN events from the EU Hub and displays them

In every shell used to run this example application, configure your environment according to the instructions provided in examples/EnvSetup.html.

Once your environment is set, change to the examples/dist/wan directory to run the application.

To run the WAN example, perform the following steps:

1. Launch a shell for the US Gateway Hub

   The US WAN Hub is a cache server gateway to the EU WAN. This gateway forwards any client updates to entries in the trades region to the EU WAN. Entry updates received from the EU WAN Hub will be distributed to its clients.

   Change to the examples/dist/wan/us-hub directory and run the following command:

   cacheserver start
   
   This command will log output like shown below:
   
   Starting CacheServer with pid: 18087
   CacheServer pid: 18087 status: running
   

2. Launch a shell for the EU Gateway Hub

   The EU WAN Hub is a cache server gateway to the US WAN. This gateway forwards any client updates to entries in the trades region to the US WAN. Entry updates received from the US WAN Hub will be distributed to its clients.

   Change to the examples/dist/wan/eu-hub directory and run the following command:

   cacheserver start
   
   This command will log output like shown below:
   
   Starting CacheServer with pid: 18686
   CacheServer pid: 18686 status: running
   

3. Launch a shell for the EU client

   Change to the examples/dist/wan/eu-client directory and run the following command:.

   The EU WAN Client listens for updates to entries in trades region.

   java wan.WANClient eu
   

   The WANClient class has a main method that creates either a US or EU WAN client using the 'us' or 'eu' parameters. Shown below is the WANClient usage.

   $ java wan.WANClient
   
   ** Missing site name
   
   usage: java wan.WANClient 
     site   The name of the WAN site (either 'us' or 'eu')
   
   Launches a WAN client
   

   This command will log output like shown below:

   Created GemFire cache: eu-client
   Retrieved region: com.gemstone.gemfire.internal.cache.LocalRegion[path='/trades';scope=LOCAL';data-type=NORMAL]
   Registered interest in [ALL_KEYS] for region trades
   

4. Launch a shell for the US client

   The US WAN Client launches mulitple threads, each putting entries into the trades region.

   Change to the examples/dist/wan/us-client directory and run the following command:

   java wan.WANClient us
   

   This command will log output like shown below:

   Created GemFire cache: us-client
   Retrieved region: com.gemstone.gemfire.internal.cache.LocalRegion[path='/trades';scope=LOCAL';data-policy=NORMAL]
   Thread-1: Putting key-704->704
   Thread-3: Putting key-2663->2663
   Thread-2: Putting key-2822->2822
   Thread-4: Putting key-853->853
   Thread-5: Putting key-3612->3612
   Thread-6: Putting key-1668->1668
   Thread-7: Putting key-1872->1872
   Thread-8: Putting key-4540->4540
   Thread-9: Putting key-442->442
   Thread-10: Putting key-1494->1494
   Thread-8: Putting key-2661->2661
   .
   .
   .
   

   In addition, output like shown below will be displayed in the EU client window:

   WANListener received afterCreate event (1) for region trades: key-853->853
   WANListener received afterUpdate event (2) for region trades: key-1494->1494
   WANListener received afterCreate event (3) for region trades: key-4540->4540
   WANListener received afterCreate event (4) for region trades: key-704->704
   WANListener received afterUpdate event (5) for region trades: key-2822->2822
   WANListener received afterCreate event (6) for region trades: key-442->442
   WANListener received afterCreate event (7) for region trades: key-1872->1872
   WANListener received afterCreate event (8) for region trades: key-2663->2663
   WANListener received afterUpdate event (9) for region trades: key-1668->1668
   WANListener received afterUpdate event (10) for region trades: key-3612->3612
   WANListener received afterCreate event (11) for region trades: key-1926->1926
   WANListener received afterUpdate event (12) for region trades: key-2661->2661
   WANListener received afterCreate event (13) for region trades: key-2372->2372
   .
   .
   .
   

5. Stop the example

   Stop the us-client and eu-client client VMs using CTL-C. Stop the us-hub and eu-hub cache server VMs using the 'cacheserver stop' command from the shell window that launched them. An example is shown below.

   cacheserver stop
   CacheServer stopped.