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| |
| <document> |
| |
| <properties> |
| <title>Turbine Services - Unique ID Service</title> |
| <author email="jvanzyl@apache.org">Jason van Zyl</author> |
| <author email="criley@ekmail.com">Cameron Riley</author> |
| </properties> |
| |
| <body> |
| |
| <section name="Unique ID Service"> |
| |
| <p> |
| The UniqueId Service is an identifier generator that provides access to Turbine |
| instance specific ID's in several different formats. |
| |
| </p> |
| |
| </section> |
| |
| <section name="Configuration"> |
| |
| <source><![CDATA[ |
| # ------------------------------------------------------------------- |
| # |
| # S E R V I C E S |
| # |
| # ------------------------------------------------------------------- |
| # Classes for Turbine Services should be defined here. |
| # Format: services.[name].classname=[implementing class] |
| # |
| # To specify properties of a service use the following syntax: |
| # service.[name].[property]=[value] |
| |
| services.UniqueIdService.classname=org.apache.turbine.services.uniqueid.TurbineUniqueIdService |
| . |
| . |
| . |
| ]]></source> |
| |
| </section> |
| |
| <section name="Usage"> |
| |
| <p> |
| The Facade class, TurbineUniqueId, exposes three methods that produce unique identifiers: |
| </p> |
| |
| <li>getInstanceId() returns an identifier for this Turbine instance that is |
| unique both on the server and worldwide.</li> |
| <li>getPseudorandomId() returns a unique identifier that looks like random data.</li> |
| <li>getUniqueId() returns an identifier that is unique within this instance but |
| does not have random-like appearance.</li> |
| |
| <p> |
| As an example of the output for these Id's, the following is a screen: |
| </p> |
| |
| <source><![CDATA[ |
| public class IdExample extends VelocityScreen |
| { |
| |
| |
| public void doBuildTemplate(RunData data , Context context) |
| throws Exception |
| { |
| |
| context.put("instanceid", TurbineUniqueId.getInstanceId()); |
| context.put("pseudorandomid", TurbineUniqueId.getPseudorandomId()); |
| context.put("uniqueid", TurbineUniqueId.getUniqueId()); |
| |
| super.doBuildTemplate(data,context); |
| |
| |
| } |
| } |
| ]]></source> |
| |
| <p> |
| With the Velocity template IdExample.vm being: |
| </p> |
| |
| <source><![CDATA[ |
| |
| InstanceId() Output example = $instanceid |
| |
| <br /> |
| |
| PseudorandomId() Output example = $pseudorandom |
| |
| <br /> |
| |
| UniqueId() Output example = $uniqueid |
| |
| ]]></source> |
| |
| <p> |
| The output is: |
| </p> |
| |
| <source><![CDATA[ |
| |
| InstanceId() Output example = EC77218EC1291E714260FDF04BCB5008 |
| PseudorandomId() Output example = otzhj954w1 |
| UniqueId() Output example = 00000000 |
| |
| ]]></source> |
| |
| |
| <p> |
| Internally Turbine uses the service for naming of temporary files stored on the |
| server as part of the Upload Service. The FileItem is named with the getInstanceId() |
| method to avoid temporary file clashes until the system retrieves the file. |
| </p> |
| |
| </section> |
| |
| </body> |
| </document> |
