/*
* Copyright 2003,2004 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.
*/
/*
*/
package org.apache.pluto.portalImpl.services;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import org.apache.pluto.portalImpl.util.Properties;
import org.apache.pluto.util.StringUtils;
/**
* Manages the life-time of services registered during servlet startup.
* There are two types of services: Services required by the container,
* and Services used for the portal driver configuration and execution.
* All services required by the container have to derive from
* {@link org.apache.pluto.services.ContainerService} and implement the
* <CODE>init()</CODE> and <CODE>destroy()</CODE> methods as appropriate.
* All services must derive from the
* {@link org.apache.pluto.portalImpl.services.Service} interface if they
* are to be used with the portal driver.
* <P>
* By registering the service and its implementation in the file
* <CODE>/config/services.properties</CODE>, the service will become
* available to the portal engine. The format of the file is simple:
*
* <PRE>
* org.apache.pluto.portalImpl.services.log.Logger = org.apache.pluto.portalImpl.services.log.LogServicesImpl
* </PRE>
*
* Each entry represents one service. The left-hand side is the abstract
* service class, the right-hand side is the implementation of this service.
* The services are initialized in the order of appearance.
*
* <P>
* Each service can have its own configuration file, located in
* <CODE>/config/services</CODE>. It has to have the name of either
* implementation or abstract class of the service, without the
* leading package name. For example, the service manager looks
* for <CODE>LoggerImpl
.properties</CODE>. This allows a special
* implementation to provide different configuration than the
* general (abstract) service requires.
*
* <P>
* If present, one of the services configuration files is loaded
* and passed to the service as {@link org.apache.pluto.portalImpl.util.Properties}
* object. Not providing a service configuration file is okay too,
* in that case the properties are emptyemptySessionPath .
*
* @see org.apache.pluto.services.ContainerService
*/
public class ServiceManager
{
private final static String SERVICES_CONFIG_FILE = "/WEB-INF/config/services.properties";
private final static String SERVICES_CONFIG_DIR = "/WEB-INF/config/services/";
/**
** Initializes all services specified in <CODE>services.properties</CODE>.
** By specifying a different implementation of the service the behaviour
** of the portal can be modified.
**
** @param aConfig
** the servlet configuration
**
** @exception Exception
** if loading <CODE>services.properties</CODE>
** or initializing any of its contained services fails
**/
public static void init (ServletConfig aConfig) throws Exception
{
init (aConfig, SERVICES_CONFIG_FILE, SERVICES_CONFIG_DIR);
}
/**
** Initializes all services specified in <CODE>services.properties</CODE>.
** By specifying a different implementation of the service the behaviour
** of the portal can be modified.
**
** @param aConfig
** the servlet configuration
** @param aServiceConfigFile
** The location of <CODE>services.properties</CODE> (relative to classpath)
** @param aServiceConfigDir
** The direcory with the services' properties files (relative to classpath)
**
** @exception Exception
** if loading <CODE>services.properties</CODE>
** or initializing any of its contained services fails
**/
public static void init (ServletConfig aConfig,
String aServiceConfigFile,
String aServiceConfigDir) throws Exception
{
// avoid duplicate initialization of services
if (! cInitialized)
{
synchronized (ServiceManager.class)
{
if (! cInitialized)
{
cInitialized = true;
}
else
{
return;
}
}
}
else
{
return;
}
ServletContext context = null;
if (aConfig != null)
context = aConfig.getServletContext ();
if (context != null)
context.log ("ServiceManager: Loading services...");
Properties props = new Properties ();
try
{
props.load (context.getResourceAsStream (aServiceConfigFile));
}
catch (IOException exc)
{
if (context != null)
context.log ("ServiceManager: File \"" + aServiceConfigFile + "\" cannot be found or read.");
throw new Exception("ServiceManager: File \"" + aServiceConfigFile + "\" cannot be found or read.");
}
int numAll = 0;
int numSuccessful = 0;
for (Iterator iter = props.names (); iter.hasNext (); )
{
String serviceBaseName = (String) iter.next ();
numAll++;
// ty to get hold of the base service
Class serviceBase;
try
{
serviceBase = Class.forName (serviceBaseName);
}
catch (ClassNotFoundException exc)
{
if (context != null)
context.log ("ServiceManager: A service with name " + serviceBaseName + " cannot be found.");
continue;
}
String serviceImplName = props.getString (serviceBaseName);
Class serviceImpl = null;
Service service = null;
try
{
serviceImpl = Class.forName (serviceImplName);
service = (Service) serviceImpl.newInstance ();
Properties serviceProps = new Properties ();
try
{
InputStream is = null;
is = context.getResourceAsStream (aServiceConfigDir + StringUtils.nameOf (serviceImpl) + ".properties");
if (is == null)
is = context.getResourceAsStream (aServiceConfigDir + StringUtils.nameOf (serviceBase) + ".properties");
if (is != null)
serviceProps.load (is);
}
catch (IOException exc)
{
// ignore -- we go without properties then
}
if (context != null)
context.log (StringUtils.nameOf (serviceBase) + " initializing...");
service.init (aConfig, serviceProps);
if (context != null)
context.log (StringUtils.nameOf (serviceBase) + " done.");
}
catch (ClassNotFoundException exc)
{
if (context != null)
context.log ("ServiceManager: A service implementation with name " + serviceImplName + " cannot be found.", exc);
continue;
}
catch (ClassCastException exc)
{
if (context != null)
context.log ("ServiceManager: Service implementation " + serviceImplName + " is not a service of the required type.", exc);
continue;
}
catch (InstantiationException exc)
{
if (context != null)
context.log ("ServiceManager: Service implementation " + serviceImplName + " cannot be instantiated.", exc);
continue;
}
catch (Exception exc)
{
if (context != null)
context.log ("ServiceManager: An unidentified error occurred", exc);
service = null;
}
if (service != null)
{
cServicesMap.put (serviceBase, service);
// build up list in reverse order for later destruction
cServicesList.add (0, service);
numSuccessful++;
}
}
if (context != null)
context.log ("ServiceManager: Services initialized (" + numSuccessful + "/" + numAll + " successful).");
if (numSuccessful!=numAll)
{
throw new Exception("ServiceManager: Services initialized (" + numSuccessful + "/" + numAll + " successful).");
}
}
/**
* Calls post init for all services
*
* @param aConfig
* the servlet configuration
**/
public static void postInit(ServletConfig aConfig) {
// avoid duplicate destruction of services
if (cInitialized)
{
synchronized (ServiceManager.class)
{
if (cInitialized)
{
cInitialized = false;
}
else
{
return;
}
}
}
else
{
return;
}
ServletContext context = null;
if (aConfig != null)
context = aConfig.getServletContext ();
// post init all services
for (Iterator iterator = cServicesList.iterator (); iterator.hasNext (); )
{
Service service = (Service) iterator.next ();
try
{
service.postInit(aConfig);
}
catch (Exception exc)
{
if (context != null)
context.log ("ServiceManager: Service couldn't be started (postInit) after init..", exc);
}
}
}
/**
** Destroys all services.
**
** @param aConfig
** the servlet configuration
**/
public static void destroy (ServletConfig aConfig)
{
// avoid duplicate destruction of services
if (cInitialized)
{
synchronized (ServiceManager.class)
{
if (cInitialized)
{
cInitialized = false;
}
else
{
return;
}
}
}
else
{
return;
}
ServletContext context = null;
if (aConfig != null)
context = aConfig.getServletContext ();
// destroy the services in reverse order
for (Iterator iterator = cServicesList.iterator (); iterator.hasNext (); )
{
Service service = (Service) iterator.next ();
try
{
service.destroy (aConfig);
}
catch (Exception exc)
{
if (context != null)
context.log ("ServiceManager: Service couldn't be destroyed.", exc);
}
}
cServicesList.clear();
cServicesMap.clear();
}
/**
** Returns the service implementation for the given service class, or
** <CODE>null</CODE> if no such service is registered.
**
** @param aClass
** the service class
**
** @return the service implementation
**/
public static Service getService (Class aClass)
{
// at this state the services map is read-only,
// therefore we can go without synchronization
return ((Service) cServicesMap.get (aClass));
}
//Start hot deploy patch
public static void hotInit (ServletConfig aConfig, String theService) throws Exception
{
hotInit (aConfig, SERVICES_CONFIG_FILE, SERVICES_CONFIG_DIR, theService);
}
public static void hotInit(ServletConfig aConfig,
String aServiceConfigFile, String aServiceConfigDir, String theService)
throws Exception {
// avoid duplicate initialization of services
if (!cInitialized) {
synchronized (ServiceManager.class) {
if (!cInitialized) {
cInitialized = true;
} else {
return;
}
}
} else {
return;
}
ServletContext context = null;
if (aConfig != null)
context = aConfig.getServletContext();
if (context != null)
context.log("ServiceManager: HOTHOT Loading service: "+theService);
Properties props = new Properties();
try {
props.load(context.getResourceAsStream(aServiceConfigFile));
} catch (IOException exc) {
if (context != null)
context.log("ServiceManager: File \"" + aServiceConfigFile
+ "\" cannot be found or read.");
throw new Exception("ServiceManager: File \"" + aServiceConfigFile
+ "\" cannot be found or read.");
}
int numAll = 0;
int numSuccessful = 0;
for (Iterator iter = props.names(); iter.hasNext();) {
String serviceBaseName = (String) iter.next();
if (serviceBaseName.equals(theService)) {
context.log("ServiceManager: Service "+theService+" FOUND!!");
numAll++;
// ty to get hold of the base service
Class serviceBase;
try {
serviceBase = Class.forName(serviceBaseName);
} catch (ClassNotFoundException exc) {
if (context != null)
context.log("ServiceManager: A service with name "
+ serviceBaseName + " cannot be found.");
continue;
}
String serviceImplName = props.getString(serviceBaseName);
Class serviceImpl = null;
Service service = null;
try {
serviceImpl = Class.forName(serviceImplName);
service = (Service) serviceImpl.newInstance();
Properties serviceProps = new Properties();
try {
InputStream is = null;
is = context.getResourceAsStream(aServiceConfigDir
+ StringUtils.nameOf(serviceImpl)
+ ".properties");
if (is == null)
is = context.getResourceAsStream(aServiceConfigDir
+ StringUtils.nameOf(serviceBase)
+ ".properties");
if (is != null)
serviceProps.load(is);
} catch (IOException exc) {
// ignore -- we go without properties then
}
if (context != null)
context.log(StringUtils.nameOf(serviceBase)
+ " initializing...");
service.init(aConfig, serviceProps);
if (context != null)
context.log(StringUtils.nameOf(serviceBase) + " done.");
} catch (ClassNotFoundException exc) {
if (context != null)
context
.log(
"ServiceManager: A service implementation with name "
+ serviceImplName
+ " cannot be found.", exc);
continue;
} catch (ClassCastException exc) {
if (context != null)
context.log("ServiceManager: Service implementation "
+ serviceImplName
+ " is not a service of the required type.",
exc);
continue;
} catch (InstantiationException exc) {
if (context != null)
context.log("ServiceManager: Service implementation "
+ serviceImplName + " cannot be instantiated.",
exc);
continue;
} catch (Exception exc) {
if (context != null)
context
.log(
"ServiceManager: An unidentified error occurred",
exc);
service = null;
}
if (service != null) {
cServicesMap.put(serviceBase, service);
// build up list in reverse order for later destruction
cServicesList.add(0,service);
numSuccessful++;
}
}
}
if (context != null)
context.log("ServiceManager: Services initialized (" + numSuccessful + "/" + numAll + " successful).");
if (numSuccessful != numAll) {
throw new Exception("ServiceManager: Services initialized (" + numSuccessful + "/" + numAll + " successful).");
}
}
public static void postHotInit(ServletConfig aConfig, String theService) {
// avoid duplicate destruction of services
if (cInitialized)
{
synchronized (ServiceManager.class)
{
if (cInitialized)
{
cInitialized = false;
}
else
{
return;
}
}
}
else
{
return;
}
ServletContext context = null;
if (aConfig != null)
context = aConfig.getServletContext ();
// post init all services
try {
Service service = (Service)cServicesMap.get(Class.forName(theService));
service.postInit(aConfig);
} catch (Exception exc) {
if (context != null)
context.log("ServiceManager:Service couldn't be started (postInit) after init..",exc);
}
}
//End hot deploy patch
// --- PRIVATE MEMBERS --- //
private static volatile boolean cInitialized = false;
private static Map cServicesMap = new HashMap ();
private static List cServicesList = new LinkedList ();
}