/*
* Copyright 2007-2008 the original author or authors.
*
* 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.
*/
package org.impalaframework.osgi.extender;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Properties;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.impalaframework.config.PrefixedCompositePropertySource;
import org.impalaframework.config.PropertySource;
import org.impalaframework.config.PropertySourceHolder;
import org.impalaframework.config.StaticPropertiesPropertySource;
import org.impalaframework.config.SystemPropertiesPropertySource;
import org.impalaframework.exception.ExecutionException;
import org.impalaframework.exception.InvalidStateException;
import org.impalaframework.facade.Impala;
import org.impalaframework.facade.InternalOperationsFacade;
import org.impalaframework.facade.ModuleManagementFacade;
import org.impalaframework.facade.OperationsFacade;
import org.impalaframework.facade.SimpleOperationsFacade;
import org.impalaframework.module.ModuleDefinitionSource;
import org.impalaframework.module.source.InternalXmlModuleDefinitionSource;
import org.impalaframework.osgi.spring.ImpalaOsgiApplicationContext;
import org.impalaframework.osgi.startup.OsgiContextStarter;
import org.impalaframework.osgi.util.OsgiUtils;
import org.impalaframework.util.ObjectUtils;
import org.impalaframework.util.PropertyUtils;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
import org.springframework.context.ApplicationContext;
import org.springframework.core.io.UrlResource;
/**
* Impala OSGi activator class. Responsible for two things: bootstrapping Impala itself, then loading the modules managed by
* Impala. The Spring configuration files used to bootstrap Impala will by default be found using the property <i>bootstrapLocations</i>
* in the file <i>impala.properties</i>, which will typically be made accessible to the activator using a fragment whose host
* is the extender bundle (that is, the bundle which contains this class). If this resource is not present, then
* the default locations "META-INF/impala-bootstrap.xml" and "META-INF/impala-osgi-bootstrap.xml" are used.
*
* The module definitions to be loaded can be done via one of two means. One, by using a <code>ModuleDefinitionSource</code>
* service, for example {@link org.impalaframework.osgi.test.InjectableModuleDefinitionSource} registered as an OSGi service.
* Two, by adding <i>moduledefinitions.xml</i> into the extender bundle, again using an extender fragment, as in the case
* with the Impala bootstrap locations.
* @author Phil Zoio
*/
public class ImpalaActivator implements BundleActivator {
private static Log logger = LogFactory.getLog(ImpalaActivator.class);
private InternalOperationsFacade operations;
private static final String[] DEFAULT_LOCATIONS = new String[] {
"META-INF/impala-bootstrap.xml",
"META-INF/impala-graph-bootstrap.xml",
"META-INF/impala-osgi-bootstrap.xml"
};
public void start(BundleContext bundleContext) throws Exception {
String[] locations = getBootstrapLocations(bundleContext);
if (logger.isDebugEnabled()) {
logger.debug("Called start for bundle context from bundle '" + bundleContext.getBundle() + "'. Activator class: " + this.getClass().getName());
}
ImpalaOsgiApplicationContext applicationContext = startContext(bundleContext, locations);
if (applicationContext != null) {
logger.info("Started Impala application context for bundle '" + bundleContext.getBundle() + "': " + applicationContext);
initApplicationContext(bundleContext, applicationContext);
} else {
logger.warn("No Impala application context started for bundle '" + bundleContext.getBundle() + "'");
}
}
void initApplicationContext(BundleContext bundleContext, ApplicationContext applicationContext) {
//TODO introduce constants for bean names
ModuleManagementFacade facade = ObjectUtils.cast(applicationContext.getBean("moduleManagementFacade"),
ModuleManagementFacade.class);
if (facade == null) {
throw new InvalidStateException("Application context '" + applicationContext.getDisplayName()
+ "' does not contain bean named 'moduleManagementFacade'");
}
setNewOperationsFacade(facade);
bundleContext.registerService(OperationsFacade.class.getName(), operations, null);
ModuleDefinitionSource moduleDefinitionSource = maybeGetModuleDefinitionSource(bundleContext, facade);
if (moduleDefinitionSource != null) {
logger.info("Found module definition source for bootstrapping Impala modules: " + moduleDefinitionSource);
operations.init(moduleDefinitionSource);
} else {
logger.info("No module definition source found for bootstrapping Impala modules. No modules loaded");
}
}
void setNewOperationsFacade(ModuleManagementFacade facade) {
operations = newOperationsFacade(facade);
Impala.init(operations);
}
InternalOperationsFacade newOperationsFacade(ModuleManagementFacade facade) {
return new SimpleOperationsFacade(facade);
}
ModuleDefinitionSource maybeGetModuleDefinitionSource(BundleContext bundleContext, ModuleManagementFacade facade) {
ModuleDefinitionSource moduleDefinitionSource = null;
//TODO use dictionary property to distinguish between possible different services with the same interface
ServiceReference serviceReference = bundleContext.getServiceReference(ModuleDefinitionSource.class.getName());
if (serviceReference != null) {
Object service = bundleContext.getService(serviceReference);
moduleDefinitionSource = ObjectUtils.cast(service, ModuleDefinitionSource.class);
if (logger.isDebugEnabled()) {
logger.debug("Found module definitionSource injected into OSGi service registry: " + moduleDefinitionSource);
}
} else {
if (logger.isDebugEnabled()) {
logger.debug("No module definitionSource injected into OSGi service registry.");
}
}
if (moduleDefinitionSource == null) {
//TODO test this with a real example
moduleDefinitionSource = maybeLoadXmlResource(bundleContext, facade);
}
return moduleDefinitionSource;
}
ModuleDefinitionSource maybeLoadXmlResource(BundleContext bundleContext, ModuleManagementFacade facade) {
URL moduleDefinitionResourceURL = getModuleDefinitionsResourceURL(bundleContext);
if (moduleDefinitionResourceURL != null) {
if (logger.isDebugEnabled()) {
logger.debug("Found module definition reource URL from bundle context: " + moduleDefinitionResourceURL);
}
InternalXmlModuleDefinitionSource source = new InternalXmlModuleDefinitionSource(facade.getModuleLocationResolver(), facade.getTypeReaderRegistry());
source.setResource(new UrlResource(moduleDefinitionResourceURL));
return source;
} else {
if (logger.isDebugEnabled()) {
logger.debug("No module definition reource URL from bundle context");
}
}
return null;
}
ImpalaOsgiApplicationContext startContext(BundleContext bundleContext, String[] locations) {
OsgiContextStarter contextStarter = newContextStarter();
contextStarter.setBundleContext(bundleContext);
ApplicationContext context = contextStarter.startContext(Arrays.asList(locations));
ImpalaOsgiApplicationContext applicationContext = ObjectUtils.cast(context, ImpalaOsgiApplicationContext.class);
return applicationContext;
}
OsgiContextStarter newContextStarter() {
OsgiContextStarter contextStarter = new OsgiContextStarter();
return contextStarter;
}
String[] getBootstrapLocations(BundleContext bundleContext) {
URL bootstrapLocationsResource = getBootstrapLocationsResourceURL(bundleContext);
String[] locations = null;
if (bootstrapLocationsResource != null) {
try {
final Properties resourceProperties = PropertyUtils.loadProperties(bootstrapLocationsResource);
//FIXME use PropertiesLoader implementation
List<PropertySource> propertySources = new ArrayList<PropertySource>();
//property value sought first in system property
propertySources.add(new SystemPropertiesPropertySource());
//then in impala properties file
propertySources.add(new StaticPropertiesPropertySource(resourceProperties));
PrefixedCompositePropertySource propertySource = new PrefixedCompositePropertySource("impala.", propertySources);
PropertySourceHolder.getInstance().setPropertySource(propertySource);
String locationString = resourceProperties.getProperty("bootstrapLocations");
if (locationString != null) {
locations = locationString.split(",");
}
if (logger.isDebugEnabled()) {
logger.debug("Using Impala bootstrap locations found from resource '" + bootstrapLocationsResource + ": " + Arrays.toString(locations));
}
} catch (ExecutionException e) {
logger.error("Unable to load Impala bootstrap resource from specified location: " + e.getMessage(), e);
throw e;
}
}
if (locations == null) {
locations = DEFAULT_LOCATIONS;
if (logger.isDebugEnabled()) {
logger.debug("Using default Impala bootstrap locations: " + Arrays.toString(locations));
}
}
return locations;
}
protected URL getBootstrapLocationsResourceURL(BundleContext bundleContext) {
//TODO allow this location to be overridden using System property
return OsgiUtils.findResource(bundleContext, "impala.properties");
}
protected URL getModuleDefinitionsResourceURL(BundleContext bundleContext) {
//TODO allow this location to be overridden using System property
return OsgiUtils.findResource(bundleContext, "moduledefinitions.xml");
}
/**
* Unloads Impala modules and shuts down Impala's {@link ApplicationContext}.
*/
public void stop(BundleContext bundleContext) throws Exception {
if (operations != null) {
operations.unloadRootModule();
operations.getModuleManagementFacade().close();
}
}
}