leosimons 2002/06/23 13:26:44
Modified: tweety/src/java/org/apache/avalon/excalibur/tweety
Tweety.java
tweety/src/java/org/apache/avalon/excalibur/tweety/demos
ChirpWorld.java
Log:
several major changes. Made tweety into an avalon component itself, so it
isn't limited from being run through the main() method. Also added quite a bit
of documentation and logging output and fixed a few bugs.
Still need to update javadocs to reference the actual documentation and
figure out what todo (see @todo) with configurable and contexualizable
components.
Revision Changes Path
1.2 +427 -78
jakarta-avalon-excalibur/tweety/src/java/org/apache/avalon/excalibur/tweety/Tweety.java
Index: Tweety.java
===================================================================
RCS file:
/home/cvs/jakarta-avalon-excalibur/tweety/src/java/org/apache/avalon/excalibur/tweety/Tweety.java,v
retrieving revision 1.1
retrieving revision 1.2
diff -u -r1.1 -r1.2
--- Tweety.java 22 Jun 2002 15:18:13 -0000 1.1
+++ Tweety.java 23 Jun 2002 20:26:44 -0000 1.2
@@ -19,90 +19,439 @@
import org.apache.avalon.framework.parameters.*;
import org.apache.avalon.framework.service.*;
import org.apache.avalon.framework.container.*;
-
+
/**
- * This is the main tweety class.
- * It reads the configuration file, and creates the components.
+ * This is the tweety engine. It is an Avalon Container, which can be used
+ * to run and manage other Avalon Components. Because it is an Avalon
+ * Component itself as well, it can easily be used in any Avalon Application.
+ *
+ * <p>The only reason tweety implements <code>Configurable</code> and
+ * <code>Contextualizable</code> is that it doesn't feel much like managing
+ * contexts or configurations for the components it manages. Instead, it
+ * simply forwards the configuration and context provided to its
components.</p>
+ *
+ * <p><b>Note: </b> Tweety has a <code>main()</code> method to allow it to be
+ * run from the commandline.
*
- [EMAIL PROTECTED] <a href="mailto:[EMAIL PROTECTED]">Nicola Ken
Barozzi</a>
- [EMAIL PROTECTED] June 20, 2002
- [EMAIL PROTECTED] 1.0
+ [EMAIL PROTECTED] <a href="mailto:[EMAIL PROTECTED]">Nicola Ken
Barozzi</a>
+ [EMAIL PROTECTED] <a href="mailto:[EMAIL PROTECTED]">Leo Simons</a>
+ [EMAIL PROTECTED] June 20, 2002
+ [EMAIL PROTECTED] 1.1
*/
-public class Tweety
+public class Tweety implements LogEnabled, Contextualizable, Configurable,
Initializable,
+ Parameterizable, Startable
{
+ //// PROPERTIES ////
+ // all our properties are protected. Since we don't provide get()/set()
+ // methods for them, this is the only way to make them accessible when
+ // subclassing.
+
+ /** we'll use this logger everywhere. It sends messages to the console.
*/
+ protected Logger m_logger;
+
+ /** all components share the same, global, Context. This is not what
should
+ really happen, but it does make Tweety a bit easier. */
+ protected Context m_context;
+
+ /** all components share the same, global, Configuration. This is not
what should
+ really happen, but it does make Tweety a bit easier. */
+ protected Configuration m_configuration;
+
+ /** all components share the same, global, ComponentManager.
+ This would not happen in a real-life setup, but it makes the
+ code simpler. */
+ protected DefaultComponentManager m_componentManager;
+
+ /** all components share the same, global, ServiceManager.
+ This would not happen in a real-life setup, but it makes the
+ code simpler. */
+ protected DefaultServiceManager m_serviceManager;
+
+ /**
+ * this field is filled during <code>parameterize()</code> with a
parameters�
+ * object that describes everything <code>Tweety</code> needs to run.
+ * Usually, it contains information loaded from a tweety.properties
file. A
+ * sample <code>tweety.properties</code> file might look like this:
+ <pre>
+########################################################################
+# tweety.properties file
+########################################################################
+#
+# Use this section to specify which components you want tweety to manage,
+# and under what role they should be put in the ComponentManager.
+# FORMAT: <role> = <javaclassname>
+
+chirp-world = org.apache.avalon.excalibur.tweety.demos.ChirpWorld
+chirp-mondo = org.apache.avalon.excalibur.tweety.demos.ChirpWorld
+ </pre>
+ * <b>Note:</b> this object is *not* shared with all the components
tweety
+ * contains, like some of the other properties of this class.
+ */
+ protected Parameters m_parameters;
+
+ /**
+ * This map will be used to store a reference to all the components
+ * that tweety will manage. We fill it up during initialize().
+ */
+ protected Map m_components;
+
+ //// CONSTRUCTOR ////
+ /**
+ * Tweety has a single, public, no arguments constructor. We supply
arguments
+ * at a later point in the form of an instance of
<code>Parameters</code>
+ * during parameterize().
+ *
+ * The constructor initializes our properties with default values.
+ */
+ public Tweety()
+ {
+ }
+
+ //// METHOD TO HANDLE RUNNING FROM COMMAND LINE ////
+ /**
+ * This method is called to invoke tweety from the command line. It
instantiates
+ * a new <code>Tweety</code> instance, provides the parameters to
configure
+ * tweety by loading them from a file, and then runs tweety itself
through its
+ * lifecycle.
+ *
+ * <b>Note:</b> we should improve this method to create a sensible
context and
+ * configuration for hosted components.
+ *
+ * @param args the command line arguments. We don't use them.
+ */
public static void main( String[] args )
{
- Logger sharedLogger = new ConsoleLogger();
- Context sharedContext = new DefaultContext();
- DefaultComponentManager sharedComponentManager = new
DefaultComponentManager();
- DefaultServiceManager sharedServiceManager = new
DefaultServiceManager();
-
- try {
-
- //load properties
- Properties properties = new Properties();
- properties.load(new FileInputStream("tweety.properties"));
-
- //this will keep references to components so we know what to
shutdown at the end
- Object[] components = new Object[properties.size()];
-
- //All the roles
- Enumeration roles = properties.propertyNames();
-
- //create and setup all the component
- for (int i=0; roles.hasMoreElements(); i++) {
-
- //Get the role of the component being setup
- String role = (String )roles.nextElement();
-
- //create the component instance
- Object component = Class.forName((String)
properties.get(role));
-
- //setup the component by running the appropriate lifecycle
methods in order
-
- ContainerUtil.enableLogging(component, sharedLogger);
- ContainerUtil.contextualize(component, sharedContext);
- ContainerUtil.compose (component,
sharedComponentManager);
- ContainerUtil.service (component, sharedServiceManager);
- //ContainerUtil.configure (component, configuration);
- //ContainerUtil.parameterize (component, parameters);
- ContainerUtil.initialize (component);
- ContainerUtil.start (component);
-
- //put the new component in the componentmanager and
servicemanager
- sharedServiceManager.put(role, component);
- if(component instanceof
org.apache.avalon.framework.component.Component){
- sharedComponentManager.put(role, (Component) component);
- }
-
- components[i]=component;
- }
-
- //
- // Here components that create threads continue operation till
they wish
- //
-
- //shutdown all the components that were set up
- for (int i=0 ; i<components.length; i++ ) {
-
- Object component = components[i];
-
- //shutdown the component by running the appropriate lifecycle
methods in order
- ContainerUtil.stop( component );
- ContainerUtil.dispose( component );
- }
-
-
- } catch (java.io.IOException ioe) {
- ioe.printStackTrace();
- System.err.println("Error reading configuration file.\nProgram
Terminated");
- System.exit(-4);
- } catch (Exception e) {
- e.printStackTrace();
- System.err.println("Error.\nProgram Terminated");
- System.exit(-2);
- }
- }
+ try
+ {
+ // create logger
+ Logger logger = new ConsoleLogger();
+
+ /** @todo: this is stupid. Figure out what to do about
contexts */
+ // create dummy context
+ Context context = new DefaultContext();
+
+ /** @todo: this is stupid. Figure out what to do about
configurations */
+ // create dummy configuration
+ Configuration config = new DefaultConfiguration( "empty
config", "nowhere" );
+
+ // load properties
+ Properties properties = new Properties();
+ properties.load(new
FileInputStream("tweety.properties"));
+
+ // create parameters from properties
+ Parameters params = new Parameters();
+ params.fromProperties( properties );
+
+ // create tweety instance
+ Tweety tweety = new Tweety();
+ tweety.enableLogging( logger );
+ tweety.contextualize( context );
+ tweety.configure( config );
+ tweety.parameterize( params );
+ tweety.initialize();
+ tweety.start();
+
+ //
+ // Here hosted components that create threads continue
operation till they wish
+ //
+
+ tweety.stop();
+ }
+ catch( java.io.IOException ioe )
+ {
+ ioe.printStackTrace();
+ System.err.println("Error reading configuration
file.\nProgram Terminated");
+ System.exit(-4);
+ }
+ catch( Exception e )
+ {
+ e.printStackTrace();
+ System.err.println("Error.\nProgram Terminated");
+ System.exit(-2);
+ }
+ }
+
+ //// AVALON FRAMEWORK LIFECYCLE METHODS ////
+ /**
+ * Provide tweety with a logger. This logger will also be used for all
the
+ * components that tweety manages.
+ *
+ * @param logger the logger
+ */
+ public void enableLogging( Logger logger )
+ {
+ m_logger = logger;
+ logger.debug( "Tweety got a logger" );
+ }
+
+ /**
+ * Provide tweety with a context. This context will also be used for all
the
+ * components that tweety manages.
+ *
+ * @param context the context
+ */
+ public void contextualize( Context context )
+ {
+ m_context = context;
+ m_logger.debug( "Tweety got a context" );
+ }
+
+ /**
+ * Provide tweety with a configuration. This configuration will also be
used for all the
+ * components that tweety manages.
+ *
+ * @param configuration the class configurations.
+ */
+ public void configure( Configuration configuration )
+ {
+ m_configuration = configuration;
+ m_logger.debug( "Tweety got a configuration" );
+ }
+
+ /**
+ * Provide tweety with the parameters it needs to run. Each pair of name
and
+ * value defines a <b>Role</b> and a component that implements that
role.
+ *
+ * @param parameters the parameters
+ * @throws ParameterException if parameters are invalid
+ */
+ public void parameterize( Parameters parameters ) throws
ParameterException
+ {
+ // check whether the supplied parameters object is valid
+ if( null == parameters || parameters.getNames().length <= 0 )
+ {
+ /* this is bad! Since there's no point in
+ running tweety without components, and there
+ is no way to specify components other than
+ during parameterize(), we throw an exception. */
+ throw new ParameterException(
+ "We need some components to take through
their lifecycle! Tjilp!" );
+
+ }
+
+ // check whether all the specified classes can be found
+ String[] roles = parameters.getNames();
+ String role = "";
+ String classname = "";
+
+ try
+ {
+ for( int i = 0; i < roles.length; i++ )
+ {
+ role = roles[i];
+ classname = parameters.getParameter( role );
+
+ // load class
+ Class.forName( classname );
+ }
+ }
+ catch( ClassNotFoundException cnfe )
+ {
+ /* this is also pretty bad. The parameters file
+ is corrupt! Throw an exception. */
+ throw new ParameterException( "The class " + classname +
+ " specified in the properties file
cannot be found" );
+ }
+
+ // we'll simply store these for later use
+ m_parameters = parameters;
+ m_logger.debug( "Tweety got its parameters" );
+ }
+
+ /**
+ * Initialize tweety. We create an instance of all the components
tweety contains.
+ */
+ public void initialize()
+ {
+ // create the list that will hold all the components
+ m_components = new HashMap();
+
+ // all the roles
+ String[] roles = m_parameters.getNames();
+
+ // loop through each of them
+ for ( int i=0; i < roles.length; i++ )
+ {
+ // Get the role of the component being setup
+ String role = roles[i];
+
+ Object component;
+ String clazz = "";
+
+ try
+ {
+ // get the class that implements that role
+ clazz = m_parameters.getParameter( role );
+
+ // create the component instance
+ component = Class.forName( clazz
).newInstance();
+
+ // add it to the list of components
+ m_components.put( role, component );
+ }
+ catch( ParameterException pe ) { /* will never happen
*/ }
+ catch( ClassNotFoundException cnfe ) { /* will never
happen */ }
+ catch( IllegalAccessException iae ) { /* will never
happen */ }
+ catch( InstantiationException ie )
+ {
+ // the component doesn't have a public no
arguments constructor!
+
+ // log error
+ m_logger.error( "The class " + clazz +
+ " specified properties file is not
a valid avalon tweety component:" +
+ " it doesn't have a public
no-arguments constructor!" );
+
+ //
+ }
+ }
+
+ m_logger.debug( "Tweety has been initialized" );
+ }
+
+ /**
+ * Start up tweety. We setup all the components tweety contains, add
them to
+ * the global componentmanager and servicemanager, and finally we call
start()
+ * on each of them.
+ */
+ public void start()
+ {
+ m_logger.info( "Tweety is starting up..." );
+
+ // get all the roles
+ Iterator it = m_components.keySet().iterator();
+
+ // loop through them
+ while( it.hasNext() )
+ {
+ // current role
+ String role = (String)it.next();
+ // component that implements the role
+ Object component = m_components.get( role );
+
+ m_logger.info( "Tweety is setting up the componet
implementing role " + role );
+
+ try
+ {
+ // setup the component by running the
appropriate lifecycle
+ // methods in order. We use a very convenient
utility to do
+ // this.
+ ContainerUtil.enableLogging(component,
m_logger);
+ ContainerUtil.contextualize(component,
m_context);
+ // note that this has been deprecated because
compose()
+ // itself has been deprecated. This is okay.
+ ContainerUtil.compose (component,
m_componentManager);
+ ContainerUtil.service (component,
m_serviceManager);
+ ContainerUtil.configure (component,
m_configuration);
+ ContainerUtil.parameterize (component,
m_parameters);
+
+ // put the new component in the servicemanager
+ m_serviceManager.put( role, component );
+
+ // put the new component in the componentmanager
+ if( component instanceof
org.apache.avalon.framework.component.Component )
+ {
+ m_componentManager.put( role,
(Component) component );
+ }
+
+ // initialize component
+ ContainerUtil.initialize (component);
+ }
+ catch( Exception e )
+ {
+ // we failed to set up this component properly!
+
+ // log the error
+ m_logger.error(
+ "We were unable to set up the
component with the role: " + role +
+ ".\n The exception thrown was:
" + e.getClass() +
+ ", with the message" +
e.getMessage() );
+
+ // remove the component from our interal list
so we don't try
+ // and start() or stop() it later
+ m_components.remove( role );
+ }
+ }
+
+ // at this point, we know for sure that all the components
still in the
+ // internal list have been setup properly.
+
+ // get all the roles
+ it = m_components.keySet().iterator();
+
+ // loop through these
+ while( it.hasNext() )
+ {
+ // current role
+ String role = (String) it.next();
+ // current component
+ Object component = m_components.get( role );
+
+ m_logger.info( "Tweety is starting the component
implementing role " + role );
+
+ try
+ {
+ // try to start it
+ ContainerUtil.start( component );
+ }
+ catch( Exception e )
+ {
+ // we failed to start this component properly!
+
+ // log the error
+ m_logger.error(
+ "We were unable to start the
component with the role: " + role +
+ ".\n The exception thrown was:
" + e.getClass().getName() +
+ ",\n with the message" +
e.getMessage() );
+
+ // remove the component from our interal list
so we don't try
+ // and stop() it later
+ m_components.remove( role );
+ }
+ }
+
+ m_logger.info( "Tweety has started." );
+ }
+
+ /**
+ * Stop tweety. For each component tweety contains, we run their
lifecycle from
+ * their stop() method right up to dispose().
+ */
+ public void stop()
+ {
+ // get all the roles
+ Iterator it = m_components.keySet().iterator();
+
+ // loop through those
+ while( it.hasNext() )
+ {
+ // current role
+ String role = (String) it.next();
+ // current component
+ Object component = m_components.get( role );
+
+ m_logger.info( "Tweety is stopping the component
implementing role " + role );
+
+ try
+ {
+ // shut down the component by running the
appropriate lifecycle
+ // methods in order. We use a very convenient
utility to do
+ // this.
+ ContainerUtil.stop( component );
+ ContainerUtil.dispose( component );
+ }
+ catch( Exception e )
+ {
+ // we failed to stop this component properly!
+ // log the problem, but don't do anything else
+ m_logger.error(
+ "We were unable to start the
component with the role: " + role +
+ ".\n The exception thrown was:
" + e.getClass().getName() +
+ ",\n with the message" +
e.getMessage() );
+ }
+ }
+
+ m_logger.info( "Tweety has stopped." );
+ }
}
1.2 +22 -25
jakarta-avalon-excalibur/tweety/src/java/org/apache/avalon/excalibur/tweety/demos/ChirpWorld.java
Index: ChirpWorld.java
===================================================================
RCS file:
/home/cvs/jakarta-avalon-excalibur/tweety/src/java/org/apache/avalon/excalibur/tweety/demos/ChirpWorld.java,v
retrieving revision 1.1
retrieving revision 1.2
diff -u -r1.1 -r1.2
--- ChirpWorld.java 22 Jun 2002 15:18:13 -0000 1.1
+++ ChirpWorld.java 23 Jun 2002 20:26:44 -0000 1.2
@@ -15,73 +15,70 @@
import org.apache.avalon.framework.parameters.*;
import org.apache.avalon.framework.service.*;
import org.apache.avalon.framework.container.*;
-
+
/**
* Just... chirps :-)
*
[EMAIL PROTECTED] <a href="mailto:[EMAIL PROTECTED]">Nicola Ken
Barozzi</a>
+ [EMAIL PROTECTED] <a href="mailto:[EMAIL PROTECTED]">Leo Simons</a>
[EMAIL PROTECTED] June 20, 2002
- [EMAIL PROTECTED] 1.0
+ [EMAIL PROTECTED] 1.0.1
*/
-
+
public class ChirpWorld implements LogEnabled, Contextualizable, Composable,
Serviceable, Initializable, Startable, Disposable
{
private Logger logger;
private Context context;
private ComponentManager cm;
- private ServiceManager sm;
-
+ private ServiceManager sm;
+
//empty constructor
- ChirpWorld(){}
+ public ChirpWorld(){}
public void enableLogging( Logger logger )
{
this.logger = logger;
- logger.debug("enableLogging called, Logger gotten");
+ logger.debug("enableLogging() called, Logger gotten");
}
public void contextualize( Context context )
{
this.context = context;
- logger.debug("contextualize called, Context gotten");
+ logger.debug("contextualize() called, Context gotten");
}
-
+
public void compose( ComponentManager cm )
{
this.cm = cm;
- logger.debug("compose called, ComponentManager gotten");
- }
+ logger.debug("compose() called, ComponentManager gotten");
+ }
public void service( ServiceManager cm )
{
this.sm = sm;
- logger.debug("service called, ServiceManager gotten");
- }
-
+ logger.debug("service() called, ServiceManager gotten");
+ }
+
public void initialize()
{
- logger.debug("initialize called");
+ logger.debug("initialize() called");
}
-
+
public void start()
{
- logger.debug("start called");
+ logger.debug("start() called");
+
+ logger.info( "I thawgt I saw a pussycat!" );
}
public void stop()
{
- logger.debug("stop called");
+ logger.debug("stop() called");
}
public void dispose()
{
logger.debug("dispose called");
}
-
-}
-
-
-
-
-
+}
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