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package com.sun.appserv.web.cache;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.logging.Logger;
import java.util.logging.Level;
import java.util.ResourceBundle;
import javax.servlet.ServletContext;
import org.apache.catalina.LifecycleException;
import com.sun.appserv.util.cache.Cache;
import com.sun.appserv.web.cache.mapping.CacheMapping;
import com.sun.enterprise.web.logging.pwc.LogDomains;
public class CacheManager {
public static final String CACHE_MANAGER_ATTR_NAME =
"com.sun.appserv.web.CacheManager";
public static final int DEFAULT_CACHE_MAX_ENTRIES = 4096;
public static final int DEFAULT_CACHE_TIMEOUT = 30;
public static final String DEFAULT_CACHE_CLASSNAME =
"com.sun.appserv.util.cache.LruCache";
// PWC_LOGGER
private static Logger _logger;
/**
* The resource bundle containing the localized message strings.
*/
private static ResourceBundle _rb = null;
// default max maximum number of entries in the cache
int maxEntries = DEFAULT_CACHE_MAX_ENTRIES;
int defaultTimeout = DEFAULT_CACHE_TIMEOUT;
String cacheClassName = DEFAULT_CACHE_CLASSNAME;
boolean enabled = false;
// application servlet context
ServletContext context;
// XXX: potentially zero or more caches?
Properties cacheProps;
Cache defaultCache;
// cache mappings indexed by the filter name
HashMap cacheMappings = new HashMap();
// default-helper, its properties
Map defaultHelperProps;
DefaultCacheHelper defaultHelper;
// cache helpers indexed by their name and filter name
HashMap helperDefs = new HashMap();
HashMap cacheHelpers = new HashMap();
HashMap cacheHelpersByFilterName = new HashMap();
// CacheManagerListener classes
ArrayList listeners = new ArrayList();
/**
* default constructor
*/
public CacheManager() { }
/**
* set the maximum number of entries of this cache
* @param maxEntries number of entries the cache should carry
*/
public void setMaxEntries(int maxEntries) {
this.maxEntries = maxEntries;
}
/**
* set the defaultTimeout of this cache
* @param defaultTimeout in seconds
*/
public void setDefaultTimeout(int defaultTimeout) {
this.defaultTimeout = defaultTimeout;
}
/**
* set the whether this is enabled
* @param enabled is this enabled?
*/
public void setEnabled(boolean enabled) {
this.enabled = enabled;
}
/**
* @return whether this is enabled
*/
public boolean isEnabled() {
return enabled;
}
/**
* add generic property
* @param name named property
* @param value value
*/
public void addProperty(String name, String value) {
if (name.equalsIgnoreCase("cacheClassName")) {
cacheClassName = value;
} else {
if (cacheProps == null) {
cacheProps = new Properties();
}
cacheProps.setProperty(name, value);
}
}
/**
* add a CacheHelper definition
* @param name CacheHelper name
* @param helperDef CacheHelper definition
*/
public void addCacheHelperDef(String name, HashMap helperDef) {
helperDefs.put(name, helperDef);
}
/**
* set the default-helper's properties
* @param map a HashMap of properties
*/
public void setDefaultHelperProps(Map map) {
this.defaultHelperProps = map;
}
/**
* set the ServletContext of this application
* @param context ServletContext
*/
public void setServletContext(ServletContext context) {
this.context = context;
}
/**
* load the helper class
* @param className of the helper
* @return CacheHelper instance
*/
private CacheHelper loadCacheHelper(String className)
throws Exception {
// use the context class loader to load class so that any
// user-defined classes in WEB-INF can also be loaded.
ClassLoader cl = Thread.currentThread().getContextClassLoader();
Class helperClass = cl.loadClass(className);
CacheHelper helper = (CacheHelper) helperClass.newInstance();
return helper;
}
/**
* Start this Context component.
* @exception LifecycleException if a startup error occurs
*/
public void start() throws LifecycleException {
if (!enabled)
return;
// web container logger
_logger = LogDomains.getLogger(LogDomains.PWC_LOGGER);
_rb = _logger.getResourceBundle();
// create the default cache
try {
defaultCache = createCache(maxEntries, cacheClassName);
} catch (Exception e) {
_logger.log(Level.WARNING, "cache.manager.excep_createCache", e);
String msg = _rb.getString("cache.manager.excep_createCache");
throw new LifecycleException(msg, e);
}
// initialize the "default" helper
defaultHelper = new DefaultCacheHelper();
defaultHelper.setCacheManager(this);
defaultHelper.init(context, defaultHelperProps);
// initialize the custom cache-helpers
Iterator helperNames = helperDefs.keySet().iterator();
while(helperNames.hasNext()) {
String name = (String) helperNames.next();
HashMap map = (HashMap)helperDefs.get(name);
try {
String className = (String)map.get("class-name");
CacheHelper helper = loadCacheHelper(className);
helper.init(context, map);
cacheHelpers.put(name, helper);
} catch (Exception e) {
String msg = _rb.getString("cache.manager.excep_initCacheHelper");
Object[] params = { name };
msg = MessageFormat.format(msg, params);
throw new LifecycleException(msg, e);
}
}
// cache-mappings are ordered by the associated filter name
Iterator filterNames = cacheMappings.keySet().iterator();
while(filterNames.hasNext()) {
String name = (String) filterNames.next();
CacheMapping mapping = (CacheMapping)cacheMappings.get(name);
String helperNameRef = mapping.getHelperNameRef();
CacheHelper helper;
if (helperNameRef == null || helperNameRef.equals("default")) {
helper = defaultHelper;
} else {
helper = (CacheHelper) cacheHelpers.get(helperNameRef);
}
cacheHelpersByFilterName.put(name, helper);
}
}
/**
* get the underlying cache name
* @return the cacheClassName
*/
public String getCacheClassName() {
return cacheClassName;
}
/**
* create the designated cache object
* @return the Cache implementation
* @throws Exception
*/
public Cache createCache() throws Exception {
return createCache(maxEntries, DEFAULT_CACHE_CLASSNAME);
}
/**
* create the designated cache object
* @return the Cache implementation
* @throws Exception
*/
public Cache createCache(int cacacity, String className)
throws Exception {
// use the context class loader to load class so that any
// user-defined classes in WEB-INF can also be loaded.
ClassLoader cl = Thread.currentThread().getContextClassLoader();
Class cacheClass = cl.loadClass(className);
Cache cacheImpl = (Cache)cacheClass.newInstance();
cacheImpl.init(maxEntries, cacheProps);
return cacheImpl;
}
/**
* get the application wide default cache expiry timeout
* @return timeout in seconds
*/
public int getDefaultTimeout() {
return defaultTimeout;
}
/**
* get the default application-wide cache
* @return cache object
*/
public Cache getDefaultCache() {
return defaultCache;
}
/**
* add cache mapping
* @param name unique name of the mapping
* @param mapping CacheMapping
*/
public void addCacheMapping(String name, CacheMapping mapping) {
cacheMappings.put(name, mapping);
}
/**
* get cacheMapping given its name
* @param name name identifying the mapping
* @return CacheMapping
*/
public CacheMapping getCacheMapping(String name) {
return (CacheMapping)cacheMappings.get(name);
}
/**
* get the helper by name
* @param name name of the cache-helper
* @return CacheHelper implementation
*/
public CacheHelper getCacheHelper(String name) {
return (CacheHelper)cacheHelpers.get(name);
}
/**
* get the helper by filter name
* @param filterName filter name
* @return CacheHelper implementation
*/
public CacheHelper getCacheHelperByFilterName(String filterName) {
return (CacheHelper)cacheHelpersByFilterName.get(filterName);
}
/**
* add CacheManagerListener object
* @param listener CacheManagerListener object
*/
public void addCacheManagerListener(CacheManagerListener listener) {
synchronized (listeners) {
listeners.add(listener);
}
}
/**
* remove CacheManagerListener object
* @param listener CacheManagerListener object
*/
public void removeCacheManagerListener(CacheManagerListener listener) {
synchronized (listeners) {
listeners.remove(listener);
}
}
/**
* enable the cache manager (and all the listeners)
*/
public void enable() {
for (int i = 0; i < listeners.size(); i++) {
CacheManagerListener listener = (CacheManagerListener)
listeners.get(i);
listener.cacheManagerEnabled();
}
}
/**
* enable the cache manager (and all the listeners)
*/
public void disable() {
for (int i = 0; i < listeners.size(); i++) {
CacheManagerListener listener = (CacheManagerListener)
listeners.get(i);
listener.cacheManagerDisabled();
}
}
/**
* Stop this Context component.
* destroy all the caches created and flush/clear the cached content
* @exception LifecycleException if a shutdown error occurs
*/
public void stop() throws LifecycleException {
disable();
try {
defaultHelper.destroy();
} catch (Exception e) {
// XXX: ignore
}
// destroy the cache-helpers
Enumeration helpers = Collections.enumeration(cacheHelpers.values());
while(helpers.hasMoreElements()) {
CacheHelper cacheHelper = (CacheHelper)helpers.nextElement();
try {
cacheHelper.destroy();
} catch (Exception e) {
// XXX: ignore
}
}
cacheHelpers.clear();
cacheMappings.clear();
cacheHelpersByFilterName.clear();
listeners.clear();
}
}
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