File	Doc	Category	Size	Date	Package
DefaultCacheHelper.java	API Doc	Glassfish v2 API	10547	Fri May 04 22:35:26 BST 2007	com.sun.appserv.web.cache

DefaultCacheHelper

• java.lang.Object

Fields Summary
private static final String[]	KEY_PREFIXES
public static final String	ATTR_CACHING_FILTER_NAME
public static final String	PROP_KEY_GENERATOR_ATTR_NAME
private static Logger	_logger
private static boolean	_isTraceEnabled
private static ResourceBundle	_rb The resource bundle containing the localized message strings.
ServletContext	context
CacheManager	manager
String	attrKeyGenerator
boolean	isKeyGeneratorChecked
CacheKeyGenerator	keyGenerator

Constructors Summary

Methods Summary
public void	destroy() Stop this Context component. exception Exception if a shutdown error occurs
public java.lang.String	getCacheKey(javax.servlet.http.HttpServletRequest request) getCacheKey: generate the key to be used to cache this request param request incoming HttpServletRequest return key string used to access the cache entry. Key is composed of: servletPath + a concatenation of the field values in the request; all key field names must be found in the appropriate scope. // cache mapping associated with the request CacheMapping mapping = lookupCacheMapping(request); if (isKeyGeneratorChecked == false && attrKeyGenerator != null) { try { keyGenerator = (CacheKeyGenerator) context.getAttribute(attrKeyGenerator); } catch (ClassCastException cce){ _logger.log(Level.WARNING, "cache.defaultHelp.illegalKeyGenerator", cce); } isKeyGeneratorChecked = true; } if (keyGenerator != null) { String key = keyGenerator.getCacheKey(context, request); if (key != null) return key; } StringBuffer sb = new StringBuffer(128); /** XXX: the StringBuffer append is a (uncontended) synchronized method. * performance hit? */ sb.append(request.getServletPath()); // append the key fields Field[] keys = mapping.getKeyFields(); for (int i = 0; i < keys.length; i++) { Object value = keys[i].getValue(context, request); // all defined key field must be present if (value == null) { if (_isTraceEnabled) { _logger.fine("DefaultCacheHelper: cannot find all the required key fields in the request " + request.getServletPath()); } return null; } sb.append(";"); sb.append(KEY_PREFIXES[keys[i].getScope()]); sb.append(keys[i].getName()); sb.append("="); sb.append(value); } return sb.toString();
public int	getTimeout(javax.servlet.http.HttpServletRequest request) get timeout for the cacheable data in this request param request incoming HttpServletRequest object return either the statically specified value or from the request fields. If not specified, get the timeout defined for the cache element. // cache mapping associated with the request CacheMapping mapping = lookupCacheMapping(request); // get the statically configured value, if any int result = mapping.getTimeout(); // if the field is not defined, return the configured value Field field = mapping.getTimeoutField(); if (field != null) { Object value = field.getValue(context, request); if (value != null) { try { // Integer type timeout object Integer timeoutAttr = Integer.valueOf(value.toString()); result = timeoutAttr.intValue(); } catch (NumberFormatException cce) { } } } // Note: this could be CacheHelper.TIMEOUT_NOT_SET return result;
public void	init(javax.servlet.ServletContext context, java.util.Map props) initialize this helper param context the web application context this helper belongs to param props helper properties this.context = context; attrKeyGenerator = (String)props.get(PROP_KEY_GENERATOR_ATTR_NAME); // web container logger _logger = LogDomains.getLogger(LogDomains.PWC_LOGGER); _isTraceEnabled = _logger.isLoggable(Level.FINE); _rb = _logger.getResourceBundle();
public boolean	isCacheable(javax.servlet.http.HttpServletRequest request) isCacheable: is the response to given request cachebale? param request incoming HttpServletRequest object return true if the response could be cached. or return false if the results of this request must not be cached. Applies pre-configured cacheability constraints in the cache-mapping; all constraints must pass for this to be cacheable. boolean result = false; // cache mapping associated with the request CacheMapping mapping = lookupCacheMapping(request); // check if the method is in the allowed methods list if (mapping.findMethod(request.getMethod())) { result = true; ConstraintField fields[] = mapping.getConstraintFields(); // apply all the constraints for (int i = 0; i < fields.length; i++) { if (!fields[i].applyConstraints(context, request)) { result = false; break; } } } return result;
public boolean	isRefreshNeeded(javax.servlet.http.HttpServletRequest request) isRefreshNeeded: is the response to given request be refreshed? param request incoming HttpServletRequest object return true if the response needs to be refreshed. or return false if the results of this request don't need to be refreshed. XXX: 04/16/02 right now there is no configurability for this in ias-web.xml; should add a refresh-field element there: boolean result = false; // cache mapping associated with the request CacheMapping mapping = lookupCacheMapping(request); Field field = mapping.getRefreshField(); if (field != null) { Object value = field.getValue(context, request); // the field's string representation must be "true" or "false" if (value != null && "true".equals(value.toString())) { result = true; } } return result;
private com.sun.appserv.web.cache.mapping.CacheMapping	lookupCacheMapping(javax.servlet.http.HttpServletRequest request) cache-mapping for this servlet-name or the URLpattern param request incoming request return cache-mapping object; uses servlet name or the URL pattern to lookup in the CacheManager for the mapping. String name = (String)request.getAttribute(ATTR_CACHING_FILTER_NAME); return manager.getCacheMapping(name);
public void	setCacheManager(CacheManager manager) set the CacheManager for this application param manager associated with this application this.manager = manager;