mcconnell 2004/04/02 21:45:25
Modified: merlin/platform/xdocs/merlin/embedded servlet.xml
Log:
Update the servlet documentation.
Revision Changes Path
1.3 +103 -61 avalon/merlin/platform/xdocs/merlin/embedded/servlet.xml
Index: servlet.xml
===================================================================
RCS file: /home/cvs/avalon/merlin/platform/xdocs/merlin/embedded/servlet.xml,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -r1.2 -r1.3
--- servlet.xml 3 Apr 2004 05:34:14 -0000 1.2
+++ servlet.xml 3 Apr 2004 05:45:25 -0000 1.3
@@ -76,31 +76,35 @@
<i>MerlinServlet.java</i>
</p>
<source>
-package org.apache.avalon.merlin.servlet;
-
-import java.io.File;
-import java.net.URL;
-import java.io.IOException;
-
-import javax.servlet.ServletException;
-import javax.servlet.ServletRequest;
-import javax.servlet.ServletResponse;
-import javax.servlet.http.HttpServlet;
-
-import org.apache.avalon.assembly.locator.DefaultLocator;
-import org.apache.avalon.merlin.kernel.Kernel;
-import org.apache.avalon.merlin.kernel.impl.DefaultKernel;
-
/**
* Servlet that handles the establishment of a Merlin Kernel
* and registration of the kernel base URL under the servlet
- * context using the key [EMAIL PROTECTED] Kernel.BASE_URL_KEY}.
- *
+ * context using the key.
+ *
+ *
* @author <a href="mailto:dev@avalon.apache.org";>Avalon Development Team</a>
*/
public class MerlinServlet extends HttpServlet
{
- private DefaultKernel m_kernel;
+ //----------------------------------------------------------
+ // static
+ //----------------------------------------------------------
+
+ private static final String MERLIN_PROPERTIES = "merlin.properties";
+
+ private static final String IMPLEMENTATION_KEY = "merlin.implementation";
+
+ //----------------------------------------------------------
+ // state
+ //----------------------------------------------------------
+
+ private KernelCriteria m_criteria;
+
+ private Kernel m_kernel;
+
+ //----------------------------------------------------------
+ // Servlet
+ //----------------------------------------------------------
/**
* Initializes Servlet by the web server container.
@@ -112,35 +116,71 @@
{
try
{
- ClassLoader loader =
Thread.currentThread().getContextClassLoader();
-
- String homePath = getServletContext().getRealPath( "." );
- File home = new File( homePath );
-
- String blockPath = getInitParameter( "block",
"BLOCK-INF/block.xml" );
- URL block = new File( home, blockPath ).toURL();
+ //
+ // get the working directory and classloader
+ //
+
+ ClassLoader classloader = MerlinServlet.class.getClassLoader();
+ String path = getServletContext().getRealPath( "." );
+ File base = new File( path );
+
+ //
+ // create the initial context using the merlin system as the
+ // initial cache
+ //
+
+ InitialContextFactory initial =
+ new DefaultInitialContextFactory( "merlin", base );
+ initial.setParentClassLoader( classloader );
+ InitialContext context = initial.createInitialContext();
+
+ //
+ // grab the merlin implmentation artifact descriptor
+ //
+
+ Artifact artifact =
+ DefaultBuilder.createImplementationArtifact(
+ classloader,
+ null,
+ base,
+ MERLIN_PROPERTIES,
+ IMPLEMENTATION_KEY );
+
+ //
+ // create and customize the kernel criteria
+ //
+
+ Builder builder = context.newBuilder( artifact );
+ Factory factory = builder.getFactory();
+ m_criteria = (KernelCriteria) factory.createDefaultCriteria();
+ m_criteria.put( "merlin.server", "true" );
+ m_criteria.put( "merlin.info", "true" );
+ m_criteria.put( "merlin.debug", "false" );
+
+ //
+ // this is where we customize content based on web.xml
+ // (currently not implemented - lets see what we can do with
+ // with merlin.properties first of all)
+ //
+
+ m_kernel = (Kernel) factory.create( m_criteria );
+ System.out.println("kernel established");
+
+ //
+ // publish the root containment model as a context attribute
+ // (this is basically exposing too much - need to wrap this
+ // in a holder that allows lookup by service interface and
+ // version
+ //
- DefaultLocator context = new DefaultLocator();
- context.put( "urn:merlin:home", home );
- context.put( "urn:merlin:system", home );
- context.put( "urn:merlin:classloader.common", loader );
- context.put( "urn:merlin:classloader.system", loader );
- context.put( "urn:merlin:debug", "WARN" );
- context.put( "urn:merlin:logging.priority", "INFO" );
- context.put( "urn:merlin:block.url", block );
- context.makeReadOnly();
-
- m_kernel = new DefaultKernel();
- m_kernel.contextualize( context );
- m_kernel.initialize();
-
- getServletContext().setAttribute( Kernel.BASE_URL_KEY,
m_kernel.getURL() );
-
- log( "kernel established" );
+ getServletContext().setAttribute(
+ "urn:composition:root", m_kernel.getModel() );
}
- catch( Exception e )
+ catch( Throwable e )
{
- throw new ServletException( "Initialization error.", e );
+ final String error = ExceptionHelper.packException( e, true );
+ System.out.println( error );
+ throw new ServletException( error, e );
}
}
@@ -150,25 +190,27 @@
public void destroy()
{
if( m_kernel != null )
- {
- m_kernel.shutdown();
- m_kernel = null;
- }
- }
-
- private String getInitParameter( final String name, final String
defaultValue )
- {
- final String value = getInitParameter( name );
- if ( null == value )
- {
- return defaultValue;
- }
- else
{
- return value;
+
+ System.out.println("tearing down");
+
+ try
+ {
+ m_kernel.shutdown();
+ }
+ catch( Throwable e )
+ {
+ final String error =
+ "Runnable kernel shutdown failure.";
+ final String msg = ExceptionHelper.packException( error, e,
true );
+ throw new RuntimeException( msg, null );
+ }
+ finally
+ {
+ m_kernel = null;
+ }
}
}
-}
</source>
</subsection>
</section>
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