package org.codehaus.plexus.component.discovery;
/*
* Copyright 2001-2005 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import org.codehaus.classworlds.ClassRealm;
import org.codehaus.plexus.component.repository.ComponentDescriptor;
import org.codehaus.plexus.component.repository.ComponentSetDescriptor;
import org.codehaus.plexus.component.repository.io.PlexusTools;
import org.codehaus.plexus.configuration.PlexusConfiguration;
import org.codehaus.plexus.configuration.PlexusConfigurationException;
import org.codehaus.plexus.configuration.PlexusConfigurationMerger;
import org.codehaus.plexus.context.Context;
import org.codehaus.plexus.context.ContextMapAdapter;
import org.codehaus.plexus.util.IOUtil;
import org.codehaus.plexus.util.InterpolationFilterReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.List;
public class PlexusXmlComponentDiscoverer
implements ComponentDiscoverer
{
private static final String PLEXUS_XML_RESOURCE = "META-INF/plexus/plexus.xml";
private ComponentDiscovererManager manager;
public void setManager( ComponentDiscovererManager manager )
{
this.manager = manager;
}
public List findComponents( Context context, ClassRealm classRealm )
throws PlexusConfigurationException
{
PlexusConfiguration configuration = discoverConfiguration( context, classRealm );
List componentSetDescriptors = new ArrayList();
ComponentSetDescriptor componentSetDescriptor = createComponentDescriptors( configuration, classRealm );
componentSetDescriptors.add( componentSetDescriptor );
// Fire the event
ComponentDiscoveryEvent event = new ComponentDiscoveryEvent( componentSetDescriptor );
manager.fireComponentDiscoveryEvent( event );
return componentSetDescriptors;
}
public PlexusConfiguration discoverConfiguration( Context context, ClassRealm classRealm )
throws PlexusConfigurationException
{
PlexusConfiguration configuration = null;
Enumeration resources = null;
try
{
resources = classRealm.findResources( PLEXUS_XML_RESOURCE );
}
catch ( IOException e )
{
throw new PlexusConfigurationException( "Error retrieving configuration resources: " + PLEXUS_XML_RESOURCE + " from class realm: " + classRealm.getId(), e );
}
for ( Enumeration e = resources; e.hasMoreElements(); )
{
URL url = (URL) e.nextElement();
InputStreamReader reader = null;
try
{
reader = new InputStreamReader( url.openStream() );
ContextMapAdapter contextAdapter = new ContextMapAdapter( context );
InterpolationFilterReader interpolationFilterReader = new InterpolationFilterReader( reader,
contextAdapter );
PlexusConfiguration discoveredConfig = PlexusTools.buildConfiguration( url.toExternalForm(), interpolationFilterReader );
if ( configuration == null )
{
configuration = discoveredConfig;
}
else
{
configuration = PlexusConfigurationMerger.merge( configuration, discoveredConfig );
}
}
catch ( IOException ex )
{
throw new PlexusConfigurationException( "Error reading configuration from: " + url.toExternalForm(), ex );
}
finally
{
IOUtil.close( reader );
}
}
return configuration;
}
private ComponentSetDescriptor createComponentDescriptors( PlexusConfiguration configuration,
ClassRealm classRealm )
throws PlexusConfigurationException
{
ComponentSetDescriptor componentSetDescriptor = new ComponentSetDescriptor();
if ( configuration != null )
{
List componentDescriptors = new ArrayList();
PlexusConfiguration[] componentConfigurations = configuration.getChild( "components" ).getChildren(
"component" );
for ( int i = 0; i < componentConfigurations.length; i++ )
{
PlexusConfiguration componentConfiguration = componentConfigurations[i];
ComponentDescriptor componentDescriptor = null;
try
{
componentDescriptor = PlexusTools.buildComponentDescriptor( componentConfiguration );
}
catch ( PlexusConfigurationException e )
{
throw new PlexusConfigurationException( "Cannot build component descriptor from resource found in:\n" +
Arrays.asList( classRealm.getConstituents() ), e );
}
componentDescriptor.setComponentType( "plexus" );
componentDescriptors.add( componentDescriptor );
}
componentSetDescriptor.setComponents( componentDescriptors );
// TODO: read and store the dependencies
}
return componentSetDescriptor;
}
}