Author: thobbs
Date: Thu Apr 19 15:17:38 2012
New Revision: 1327987
URL: http://svn.apache.org/viewvc?rev=1327987&view=rev
Log:
CMS commit to river by thobbs
Modified:
river/site/trunk/content/helloworld.mdtext
Modified: river/site/trunk/content/helloworld.mdtext
URL:
http://svn.apache.org/viewvc/river/site/trunk/content/helloworld.mdtext?rev=1327987&r1=1327986&r2=1327987&view=diff
==============================================================================
--- river/site/trunk/content/helloworld.mdtext (original)
+++ river/site/trunk/content/helloworld.mdtext Thu Apr 19 15:17:38 2012
@@ -16,4 +16,139 @@ Notice: Licensed to the Apache Softwa
specific language governing permissions and limitations
under the License.
-Hello World with River
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+# Hello World With River
+
+**Experimental**<br/>
+Warning! The following describes how to use code which is currently only
contained in a branch of River and has not been formally released yet.
+
+## Introduction
+It can be argued that part of the barrier to entry of getting working River
services is the complexity and difficulty with configuring services. The are
many things that users, new and old, must remember when trying to set up new
environments and tweak the configurations of their services.
+
+The configurations themselves can be tempermental and difficult for new comers
to get to grips with. Largely, they are text files with a Java-esque content
which is parsed by the <font face="Courier">ServiceStarter</font>. The
following describes how to use the "extra" bits of River to get around these
issues.
+
+## Extra River
+The classes required in this documentation live outside of the main River
distribution, in fact they are not part of the core of the library neither are
they part of the Jini and JavaSpaces specifications. In a standard River
install, they are therefore completely optional.
+
+## Getting Started
+
+### Prerequisites
+
+River Extras require the following additional JARs on their runtime classpath.
+
+* Apache Commons Collections 3.2
+* Apache Commons Lang 2.6
+
+From now on, this document will refer to these two exact file system locatino
of these JARs as;
+
+ * <pre>${COMMONS_COLLECTIONS_JAR}</pre>
+ * <pre>${COMMONS_LANG_JAR}</pre>
+
+### Getting the Code and Building River
+
+You must first get the River source. Since this code is still experimental,
that means checking out the code from a trunk. Ideally, this code will make
the next release and so will come packaged as part of the River (source)
distribution.
+
+<pre>
+$ cd ~/projects/river
+$ svn co http://svn.apache.org/repos/asf/river/jtsk/skunk/easystart helloworld
+$ cd helloworld
+$ ant # This will build the River distribution, including the lib/extra.jar
+</pre>
+
+Optionally, you can also;
+<pre>
+$ cd ../src-extra-examples
+$ ant # This will build the lib/extra-examples.jar
+</pre>
+
+From this point on, we shall refer to the installation of River as
<code>${RIVER_HOME}</code>. In this example, it would refer to directory
~/projects/river/helloworld.
+
+### Starting the HTTP Server
+
+Jini/River services of course require a HTTP server. This is easily started
in such a way as it will serve all the JAR files from the ${RIVER_HOME}/lib
directory.
+
+Open your IDE of choice, fix any build/setup errors and then setup a run
configuration for the HTTP server - I use Eclipse, hence the terminology.
+
+The main class to run is,
<code>org.apache.river.extra.examples.easystart.riverservices.StartHttpServer</code>
and can be found in the <code>${RIVER_HOME}/src-extra-examples</code> source
directory. It will need the following program arguments;
+
+* ~/projects/river/helloworld
+* 8080
+
+Obviously, the first argument is the value of <code>${RIVER_HOME}</code> and
the second is the HTTP port to use. This is the default port according to
River Extras, if you want to use a different port then this will require
changes (in Java code) of the configuration.
+
+Execute this run configuration and leave it running. You can verify that it's
working correctly by using your browser or <code>wget</code> to download a
sample JAR, e.g.
+
+<code>$ wget http://localhost:8080/reggie.jar</code>
+
+The rest of this document describes code that can be found in the
<code>src-extra</code> and <code>src-extra-examples</code> source directories.
+
+### Common Service Configuration Options
+
+We are going to use a <code>ApplicationOptions</code> to describe certain
service configuration options that will be common to all the services we're
going to start. From,
<code>org.apache.river.extra.examples.easystart.StartServices</code>;
+
+<code>
+ApplicationOptions options = new ApplicationOptions();<br/>
+options.setJiniPort(4162);<br/>
+options.setHttpOptions("localhost", 8080, true);<br/>
+options.addLookupGroup("extra").addLookupGroup("example");<br/>
+options.setPackageName(ExampleService.PACKAGE);<br/>
+</code>
+
+So you can see we are using the non-default Jini port (4162). We are also
setting the configuration package name of our services to some constant as
defined in <code>ExampleService.PACKAGE</code>.
+
+We shall describe <code>ExampleService</code> later.
+
+Next we need a factory to build our configuration objects;
+
+<code>
+ApplicationConfigurationFactory configFac = new
ApplicationConfigurationFactory(options);
+</code>
+
+This class extends a non-example River Extra class,
<code>org.apache.river.extra.easystart.config.ConfigurationFactory</code>.
This base class knows how to create configuration objects for the standard
River services using the djinn specific options as we have described above, the
extending class also knows how to create configuration objects for our
additional custom services.
+
+### Starting the Lookup Service
+
+Staying with the same <code>StartServices</code> class from above.
+
+First we need to config the lookup service and then we can start it. This is
easily done;
+
+<code>
+LookupServiceConfiguration lusConfig = configFac.lookupServiceConfig();<br/>
+lusConfig.addMemberGroup("extra").addMemberGroup("extra");<br/>
+ServiceStarter.main(lusConfig.riverConfig());<br/>
+</code>
+
+Notice that we have set the lookup service's configuration's member groups to
be the same as the lookup groups as defined in the
<code>ApplicationOptions</code> instance above.
+
+We now have a started lookup service.
+
+### Starting the Example Service
+
+Next we need a configuration for our example service.
+
+The configuration is described in our extended
<code>ApplicationConfigurationFactory</code>, thus;
+
+<code>
+public AbstractEasyConfiguration exampleService(Name name) {<br/>
+ ApplicationOptions exampleOptions =
getDefaultOptions();<br/>
+ exampleOptions.setImplementationClass(ExampleServiceImpl.class);<br/>
+ exampleOptions.addInitialLookupAttribute(name);<br/>
+ return new AbstractEasyConfiguration(exampleOptions)
{};<br/>
+}
+</code>
+
+Now we know how the configuration was done. You should also be able to see
how easy it will be to extend this concept of ConfigurationFactory to handle
all of your own custom services that make up your own applications.
+
+We can start the example service in exactly the same way as we did the lookup
service previously.
+
+<code>
+AbstractEasyConfiguration config = configFac.exampleService(new Name("Jeff"));
+ServiceStarter.main(config.riverConfig());
+</code>
+
+Now we have successfully configured and started our example service, and in
all of this we did not have to bother ourselves with any configuration file.
+
+It should be pointed out that the services we have started are using the
default policy file which is unsuitable for a live environment, since it is a
"grant all" policy file that can be found in
<code>${RIVER_HOME}/src-extra/policy.all</code>
+
+## Additional Configuration
+
+You can specify additional configuration data by creating custom
<code>org.apache.river.extra.easystart.config.settings.Setting</code> objects
and adding them to the
<code>org.apache.river.extra.easystart.config.ApplicationOptions</code>
instance before creating your configuration factory. In the same package,
there are additional extending classes of <code>Setting</code> that can be used
as templates for your own configuration options.
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