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SUMMARY: JavaDoc of org.apache.tapestry.engine.AbstractEngine JAVADOC | Sourc code of org.apache.tapestry.engine.AbstractEngine SOURCE | Download org.apache.tapestry.engine.AbstractEngine DOWNLOAD | NESTED | FIELD | CONSTR | METHOD DETAIL: FIELD | CONSTR | METHOD

org.apache.tapestry.engine
Class AbstractEngine  view AbstractEngine download AbstractEngine.java

java.lang.Object
  extended byorg.apache.tapestry.engine.AbstractEngine
All Implemented Interfaces:
java.util.EventListener, java.io.Externalizable, javax.servlet.http.HttpSessionBindingListener, org.apache.tapestry.IEngine, IEngineServiceView, java.io.Serializable
Direct Known Subclasses:
BaseEngine
public abstract class AbstractEngine
extends java.lang.Object
implements org.apache.tapestry.IEngine, IEngineServiceView, java.io.Externalizable, javax.servlet.http.HttpSessionBindingListener

Basis for building real Tapestry applications. Immediate subclasses provide different strategies for managing page state and other resources between request cycles.

Note: much of this description is in transition as part of Tapestry 3.1. All ad-hoc singletons and such are being replaced with HiveMind services.

Uses a shared instance of ITemplateSource,ISpecificationSource, IScriptSourceand IComponentMessagesSourcestored as attributes of the javax.servlet.ServletContext(they will be shared by all sessions).

An engine is designed to be very lightweight. Particularily, it should never hold references to any org.apache.tapestry.IPageor org.apache.tapestry.IComponentobjects. The entire system is based upon being able to quickly rebuild the state of any page(s).

Where possible, instance variables should be transient. They can be restored inside setupForRequest(RequestContext) 55 .

In practice, a subclass (usually BaseEngine) is used without subclassing. Instead, a visit object is specified. To facilitate this, the application specification may include a property, org.apache.tapestry.visit-class which is the class name to instantiate when a visit object is first needed. See createVisit(IRequestCycle) 55 for more details.

Some of the classes' behavior is controlled by JVM system properties (typically only used during development):
Property Description
org.apache.tapestry.enable-reset-service If true, enabled an additional service, reset, that allow page, specification and template caches to be cleared on demand. See isResetServiceEnabled() 55 .
org.apache.tapestry.disable-caching If true, then the page, specification, template and script caches will be cleared after each request. This slows things down, but ensures that the latest versions of such files are used. Care should be taken that the source directories for the files preceeds any versions of the files available in JARs or WARs.

Field Summary
static com.cortexeb.tools.clover.d __CLOVER_71_0
           
private  java.lang.String _clientAddress
           
private  java.lang.String _contextPath
           
private  boolean _dirty
          Set to true when there is a (potential) change to the internal state of the engine, set to false when the engine is stored into the javax.servlet.http.HttpSession.
private static boolean _disableCaching
          If true (set from the JVM system parameter org.apache.tapestry.disable-caching) then the cache of pages, specifications and template will be cleared after each request.
private  java.lang.Object _global
          The globally shared application object.
private  org.apache.tapestry.services.Infrastructure _infrastructure
          The link to the world of HiveMind services.
private  org.apache.tapestry.listener.ListenerMap _listeners
           
private  java.util.Locale _locale
          The curent locale for the engine, which may be changed at any time.
private  boolean _localeChanged
          Set by setLocale(Locale) 55 when the locale is changed; this allows the locale cookie to be updated.
private  IMonitorFactory _monitorFactory
          The instance of IMonitorFactoryused to create a monitor.
private static boolean _resetServiceEnabled
          If true (set from JVM system parameter org.apache.tapestry.enable-reset-service) then the reset service will be enabled, allowing the cache of pages, specifications and template to be cleared on demand.
private  java.lang.String _servletPath
           
private  java.lang.String _sessionId
           
private  boolean _stateful
           
private  java.lang.Object _visit
          An object used to contain application-specific server side state.
static java.lang.String DEFAULT_OUTPUT_ENCODING
          The default encoding that will be used when generating the output.
static java.lang.String GLOBAL_NAME
          The base name for the servlet context key used to store the application-defined Global object, if any.
private static org.apache.commons.logging.Log LOG
           
static java.lang.String OUTPUT_ENCODING_PROPERTY_NAME
          The name of the application property that will be used to determine the encoding to use when generating the output
private static long serialVersionUID
           
static java.lang.String VISIT_CLASS_PROPERTY_NAME
          The name of the application specification property used to specify the class of the visit object.
 
Fields inherited from interface org.apache.tapestry.IEngine
EXCEPTION_PAGE, HOME_PAGE, STALE_LINK_PAGE, STALE_SESSION_PAGE
 
Constructor Summary
AbstractEngine()
           
 
Method Summary
protected  void activateExceptionPage(org.apache.tapestry.IRequestCycle cycle, org.apache.tapestry.request.ResponseOutputStream output, java.lang.Throwable cause)
          Sets the Exception page's exception property, then renders the Exception page.
protected abstract  void cleanupAfterRequest(org.apache.tapestry.IRequestCycle cycle)
          Invoked at the end of the request cycle to release any resources specific to the request cycle.
 void clearCachedData()
          Discards all cached pages, component specifications and templates.
protected  java.lang.Object createGlobal(org.apache.tapestry.request.RequestContext context)
          Creates the shared Global object.
protected  org.apache.tapestry.IRequestCycle createRequestCycle(org.apache.tapestry.request.RequestContext context, IEngineService service, IMonitor monitor)
          Invoked from service(RequestContext) 55 to create an instance of org.apache.tapestry.IRequestCycle for the current request.
protected  java.lang.Object createVisit(org.apache.tapestry.IRequestCycle cycle)
          Invoked to lazily create a new visit object when it is first referenced (by getVisit(IRequestCycle) 55 ).
protected  void extendDescription(org.apache.commons.lang.builder.ToStringBuilder builder)
          Extends the description of the class generated by toString() 55 .
protected  java.lang.String extractServiceName(org.apache.tapestry.request.RequestContext context)
          Invoked from service(RequestContext) 55 to extract, from the URL, the name of the service.
abstract  java.util.Collection getActivePageNames()
          Implemented by subclasses to return the names of the active pages (pages for which recorders exist).
 org.apache.hivemind.ClassResolver getClassResolver()
          Returns an object that can resolve resources and classes.
 IComponentClassEnhancer getComponentClassEnhancer()
          Returns an object that can create enhanced versions of component classes.
 org.apache.tapestry.services.ComponentMessagesSource getComponentMessagesSource()
          Returns a shared object that allows components to find their set of localized strings.
 java.lang.String getContextPath()
          Returns the context path, the prefix to apply to any URLs so that they are recognized as belonging to the Servlet 2.2 context.
 org.apache.tapestry.services.DataSqueezer getDataSqueezer()
          Returns a shared instance of org.apache.tapestry.util.io.DataSqueezerImpl.
protected  java.lang.String getDefaultOutputEncoding()
          The encoding to be used if none has been defined using the output encoding property.
protected  java.lang.String getExceptionPageName()
           
 java.lang.Object getGlobal()
          Returns the global object for the application.
 boolean getHasVisit()
           
 org.apache.tapestry.listener.ListenerMap getListeners()
          Allows subclasses to include listener methods easily.
 java.util.Locale getLocale()
          Returns the locale for the engine.
 IMonitor getMonitor(org.apache.tapestry.request.RequestContext context)
          Overriden in subclasses that support monitoring.
 java.lang.String getOutputEncoding()
          Returns the encoding to be used to generate the servlet responses and accept the servlet requests.
 IPageSource getPageSource()
          Returns the object used to load a page from its specification.
 org.apache.tapestry.services.ObjectPool getPool()
          Returns a org.apache.tapestry.util.pool.Pool that is used to store all manner of objects that are needed throughout the system.
 IPropertySource getPropertySource()
          Returns a IPropertySource that should be used to obtain configuration data.
 IScriptSource getScriptSource()
          Returns a source for parsed org.apache.tapestry.IScripts.
 IEngineService getService(java.lang.String name)
          Returns a service with the given name.
 java.lang.String getServletPath()
          Returns the URL path that corresponds to the servlet for the application.
 org.apache.tapestry.spec.IApplicationSpecification getSpecification()
          Returns the application specification that defines the application and its pages.
 ISpecificationSource getSpecificationSource()
          Returns the source of all component specifications for the application.
protected  java.lang.String getStaleLinkPageName()
           
protected  java.lang.String getStaleSessionPageName()
           
 org.apache.tapestry.services.TemplateSource getTemplateSource()
          Returns the source for HTML templates.
 java.lang.Object getVisit()
          Gets the visit object, if it has been created already.
 java.lang.Object getVisit(org.apache.tapestry.IRequestCycle cycle)
          Gets the visit object, invoking createVisit(IRequestCycle) 55 to create it lazily if needed.
protected  void handlePageRedirectException(org.apache.tapestry.PageRedirectException ex, org.apache.tapestry.IRequestCycle cycle, org.apache.tapestry.request.ResponseOutputStream output)
          Handles org.apache.tapestry.PageRedirectExceptionwhich involves executing IPage.validate(IRequestCycle)>IPage.validate(IRequestCycle) 55 on the target page (of the exception), until either a loop is found, or a page succesfully validates and can be activated.
protected  void handleRedirectException(org.apache.tapestry.IRequestCycle cycle, org.apache.tapestry.RedirectException ex)
          Invoked when a org.apache.tapestry.RedirectExceptionis thrown during the processing of a request.
protected  void handleStaleLinkException(org.apache.tapestry.StaleLinkException ex, org.apache.tapestry.IRequestCycle cycle, org.apache.tapestry.request.ResponseOutputStream output)
          Invoked by service(RequestContext) 55 if a org.apache.tapestry.StaleLinkExceptionis thrown by the service.
protected  void handleStaleSessionException(org.apache.tapestry.StaleSessionException ex, org.apache.tapestry.IRequestCycle cycle, org.apache.tapestry.request.ResponseOutputStream output)
          Invoked by service(RequestContext) 55 if a org.apache.tapestry.StaleSessionExceptionis thrown by the service.
 boolean isDirty()
          Returns true if the engine has (potentially) changed state since the last time it was stored into the javax.servlet.http.HttpSession.
 boolean isResetServiceEnabled()
          Returns true if the reset service is curently enabled.
 boolean isStateful()
          Returns true if the engine has state and, therefore, should be stored in the HttpSession.
protected  void markDirty()
          Invoked to set the dirty flag, indicating that the engine should be stored into the javax.servlet.http.HttpSession.
 void readExternal(java.io.ObjectInput in)
          Reads the state serialized by writeExternal(ObjectOutput) 55 .
protected  void redirect(java.lang.String pageName, org.apache.tapestry.IRequestCycle cycle, org.apache.tapestry.request.ResponseOutputStream out, org.apache.hivemind.ApplicationRuntimeException exception)
          Invoked, typically, when an exception occurs while servicing the request.
 void renderResponse(org.apache.tapestry.IRequestCycle cycle, org.apache.tapestry.request.ResponseOutputStream output)
          Invoked by a service to force the page selected by the org.apache.tapestry.IRequestCycle to be renderred.
 void reportException(java.lang.String reportTitle, java.lang.Throwable ex)
          Writes a detailed report of the exception to System.err.
 void restart(org.apache.tapestry.IRequestCycle cycle)
          Invalidates the session, then redirects the client web browser to the servlet's prefix, starting a new visit.
 boolean service(org.apache.tapestry.request.RequestContext context)
          Delegate method for the servlet.
 void setLocale(java.util.Locale value)
          Changes the locale for the engine.
protected  void setStateful()
          Invoked by subclasses to indicate that some state must now be stored in the engine (and that the engine should now be stored in the HttpSession).
protected  void setupForRequest(org.apache.tapestry.request.RequestContext context)
          Invoked from service(RequestContext) 55 to ensure that the engine's instance variables are setup.
 void setVisit(java.lang.Object value)
          Updates the visit object and sets the dirty flag 55 .
 java.lang.String toString()
          Generates a description of the instance.
 void valueBound(javax.servlet.http.HttpSessionBindingEvent arg0)
          Clears the dirty flag when a engine is stored into the javax.servlet.http.HttpSession.
 void valueUnbound(javax.servlet.http.HttpSessionBindingEvent arg0)
          Does nothing.
 void writeExternal(java.io.ObjectOutput out)
          Writes the following properties: locale name (Locale.toString()>Locale.toString() 55 ) visit
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface org.apache.tapestry.IEngine
createPageRecorder, forgetPage, getPageRecorder
 

Field Detail

__CLOVER_71_0

public static com.cortexeb.tools.clover.d __CLOVER_71_0

LOG

private static final org.apache.commons.logging.Log LOG

serialVersionUID

private static final long serialVersionUID
Since:
2.0.4
See Also:
Constant Field Values

_infrastructure

private transient org.apache.tapestry.services.Infrastructure _infrastructure
The link to the world of HiveMind services.

Since:
3.1

_contextPath

private transient java.lang.String _contextPath

_servletPath

private transient java.lang.String _servletPath

_clientAddress

private transient java.lang.String _clientAddress

_sessionId

private transient java.lang.String _sessionId

_stateful

private transient boolean _stateful

_listeners

private transient org.apache.tapestry.listener.ListenerMap _listeners

_visit

private java.lang.Object _visit
An object used to contain application-specific server side state.

_global

private transient java.lang.Object _global
The globally shared application object. Typically, this is created when first needed, shared between sessions and engines, and stored in the javax.servlet.ServletContext.

Since:
2.3

GLOBAL_NAME

public static final java.lang.String GLOBAL_NAME
The base name for the servlet context key used to store the application-defined Global object, if any.

Since:
2.3
See Also:
Constant Field Values

OUTPUT_ENCODING_PROPERTY_NAME

public static final java.lang.String OUTPUT_ENCODING_PROPERTY_NAME
The name of the application property that will be used to determine the encoding to use when generating the output

Since:
3.0
See Also:
Constant Field Values

DEFAULT_OUTPUT_ENCODING

public static final java.lang.String DEFAULT_OUTPUT_ENCODING
The default encoding that will be used when generating the output. It is used if no output encoding property has been specified.

Since:
3.0
See Also:
Constant Field Values

_locale

private java.util.Locale _locale
The curent locale for the engine, which may be changed at any time.

_localeChanged

private boolean _localeChanged
Set by setLocale(Locale) 55 when the locale is changed; this allows the locale cookie to be updated.

VISIT_CLASS_PROPERTY_NAME

public static final java.lang.String VISIT_CLASS_PROPERTY_NAME
The name of the application specification property used to specify the class of the visit object.

See Also:
Constant Field Values

_resetServiceEnabled

private static final boolean _resetServiceEnabled
If true (set from JVM system parameter org.apache.tapestry.enable-reset-service) then the reset service will be enabled, allowing the cache of pages, specifications and template to be cleared on demand.

_disableCaching

private static final boolean _disableCaching
If true (set from the JVM system parameter org.apache.tapestry.disable-caching) then the cache of pages, specifications and template will be cleared after each request.

_dirty

private transient boolean _dirty
Set to true when there is a (potential) change to the internal state of the engine, set to false when the engine is stored into the javax.servlet.http.HttpSession.

Since:
3.0

_monitorFactory

private transient IMonitorFactory _monitorFactory
The instance of IMonitorFactoryused to create a monitor.

Since:
3.0
Constructor Detail

AbstractEngine

public AbstractEngine()
Method Detail

activateExceptionPage

protected void activateExceptionPage(org.apache.tapestry.IRequestCycle cycle,
                                     org.apache.tapestry.request.ResponseOutputStream output,
                                     java.lang.Throwable cause)
                              throws javax.servlet.ServletException
Sets the Exception page's exception property, then renders the Exception page.

If the render throws an exception, then copious output is sent to System.err and a javax.servlet.ServletExceptionis thrown.

reportException

public void reportException(java.lang.String reportTitle,
                            java.lang.Throwable ex)
Writes a detailed report of the exception to System.err.

Specified by:
reportException in interface IEngineServiceView

cleanupAfterRequest

protected abstract void cleanupAfterRequest(org.apache.tapestry.IRequestCycle cycle)
Invoked at the end of the request cycle to release any resources specific to the request cycle.

extendDescription

protected void extendDescription(org.apache.commons.lang.builder.ToStringBuilder builder)
Extends the description of the class generated by toString() 55 . If a subclass adds additional instance variables that should be described in the instance description, it may overide this method. This implementation does nothing.

getLocale

public java.util.Locale getLocale()
Returns the locale for the engine. This is initially set by the org.apache.tapestry.ApplicationServlet but may be updated by the application.

Specified by:
getLocale in interface org.apache.tapestry.IEngine

getMonitor

public IMonitor getMonitor(org.apache.tapestry.request.RequestContext context)
Overriden in subclasses that support monitoring. Should create and return an instance of IMonitorthat is appropriate for the request cycle described by the org.apache.tapestry.request.RequestContext.

The monitor is used to create a RequestCycle.

This implementation uses a IMonitorFactoryto create the monitor instance. The factory is provided as an application extension. If the application extension does not exist, DefaultMonitorFactoryis used.

As of release 3.0, this method should not return null.

getPageSource

public IPageSource getPageSource()
Description copied from interface: org.apache.tapestry.IEngine
Returns the object used to load a page from its specification.

Specified by:
getPageSource in interface org.apache.tapestry.IEngine

getService

public IEngineService getService(java.lang.String name)
Returns a service with the given name.

Specified by:
getService in interface org.apache.tapestry.IEngine

getServletPath

public java.lang.String getServletPath()
Description copied from interface: org.apache.tapestry.IEngine
Returns the URL path that corresponds to the servlet for the application. This is required by instances of IEngineService that need to construct URLs for the application. This value will include the context path.

Specified by:
getServletPath in interface org.apache.tapestry.IEngine

getContextPath

public java.lang.String getContextPath()
Returns the context path, the prefix to apply to any URLs so that they are recognized as belonging to the Servlet 2.2 context.

Specified by:
getContextPath in interface org.apache.tapestry.IEngine

getSpecification

public org.apache.tapestry.spec.IApplicationSpecification getSpecification()
Description copied from interface: org.apache.tapestry.IEngine
Returns the application specification that defines the application and its pages.

Specified by:
getSpecification in interface org.apache.tapestry.IEngine

getSpecificationSource

public ISpecificationSource getSpecificationSource()
Description copied from interface: org.apache.tapestry.IEngine
Returns the source of all component specifications for the application. The source is shared between sessions.

Specified by:
getSpecificationSource in interface org.apache.tapestry.IEngine

getTemplateSource

public org.apache.tapestry.services.TemplateSource getTemplateSource()
Description copied from interface: org.apache.tapestry.IEngine
Returns the source for HTML templates.

Specified by:
getTemplateSource in interface org.apache.tapestry.IEngine

readExternal

public void readExternal(java.io.ObjectInput in)
                  throws java.io.IOException,
                         java.lang.ClassNotFoundException
Reads the state serialized by writeExternal(ObjectOutput) 55 .

This always set the stateful flag. By default, a deserialized session is stateful (else, it would not have been serialized).

Specified by:
readExternal in interface java.io.Externalizable

writeExternal

public void writeExternal(java.io.ObjectOutput out)
                   throws java.io.IOException
Writes the following properties:

Specified by:
writeExternal in interface java.io.Externalizable

redirect

protected void redirect(java.lang.String pageName,
                        org.apache.tapestry.IRequestCycle cycle,
                        org.apache.tapestry.request.ResponseOutputStream out,
                        org.apache.hivemind.ApplicationRuntimeException exception)
                 throws java.io.IOException,
                        javax.servlet.ServletException
Invoked, typically, when an exception occurs while servicing the request. This method resets the output, sets the new page and renders it.

renderResponse

public void renderResponse(org.apache.tapestry.IRequestCycle cycle,
                           org.apache.tapestry.request.ResponseOutputStream output)
                    throws javax.servlet.ServletException,
                           java.io.IOException
Description copied from interface: IEngineServiceView
Invoked by a service to force the page selected by the org.apache.tapestry.IRequestCycle to be renderred. This takes care of a number of bookkeeping issues, such as committing changes in page recorders.

Specified by:
renderResponse in interface IEngineServiceView

restart

public void restart(org.apache.tapestry.IRequestCycle cycle)
             throws java.io.IOException
Invalidates the session, then redirects the client web browser to the servlet's prefix, starting a new visit.

Subclasses should perform their own restart (if necessary, which is rarely) before invoking this implementation.

Specified by:
restart in interface IEngineServiceView

service

public boolean service(org.apache.tapestry.request.RequestContext context)
                throws javax.servlet.ServletException,
                       java.io.IOException
Delegate method for the servlet. Services the request.

Specified by:
service in interface org.apache.tapestry.IEngine

handlePageRedirectException

protected void handlePageRedirectException(org.apache.tapestry.PageRedirectException ex,
                                           org.apache.tapestry.IRequestCycle cycle,
                                           org.apache.tapestry.request.ResponseOutputStream output)
                                    throws java.io.IOException,
                                           javax.servlet.ServletException
Handles org.apache.tapestry.PageRedirectExceptionwhich involves executing IPage.validate(IRequestCycle)>IPage.validate(IRequestCycle) 55 on the target page (of the exception), until either a loop is found, or a page succesfully validates and can be activated.

This should generally not be overriden in subclasses.

Since:
3.0

createRequestCycle

protected org.apache.tapestry.IRequestCycle createRequestCycle(org.apache.tapestry.request.RequestContext context,
                                                               IEngineService service,
                                                               IMonitor monitor)
Invoked from service(RequestContext) 55 to create an instance of org.apache.tapestry.IRequestCycle for the current request. This implementation creates an returns an instance of RequestCycle.

Since:
3.0

handleStaleLinkException

protected void handleStaleLinkException(org.apache.tapestry.StaleLinkException ex,
                                        org.apache.tapestry.IRequestCycle cycle,
                                        org.apache.tapestry.request.ResponseOutputStream output)
                                 throws java.io.IOException,
                                        javax.servlet.ServletException
Invoked by service(RequestContext) 55 if a org.apache.tapestry.StaleLinkExceptionis thrown by the service. This implementation sets the message property of the StaleLink page to the message provided in the exception, then invokes redirect(String, IRequestCycle, ResponseOutputStream, ApplicationRuntimeException) 55 to render the StaleLink page.

Subclasses may overide this method (without invoking this implementation). A common practice is to present an error message on the application's Home page.

Alternately, the application may provide its own version of the StaleLink page, overriding the framework's implementation (probably a good idea, because the default page hints at "application errors" and isn't localized). The overriding StaleLink implementation must implement a message property of type String.

Since:
0.2.10

handleStaleSessionException

protected void handleStaleSessionException(org.apache.tapestry.StaleSessionException ex,
                                           org.apache.tapestry.IRequestCycle cycle,
                                           org.apache.tapestry.request.ResponseOutputStream output)
                                    throws java.io.IOException,
                                           javax.servlet.ServletException
Invoked by service(RequestContext) 55 if a org.apache.tapestry.StaleSessionExceptionis thrown by the service. This implementation invokes redirect(String, IRequestCycle, ResponseOutputStream, ApplicationRuntimeException) 55 to render the StaleSession page.

Subclasses may overide this method (without invoking this implementation). A common practice is to present an eror message on the application's Home page.

Since:
0.2.10

clearCachedData

public void clearCachedData()
Discards all cached pages, component specifications and templates. Subclasses who override this method should invoke this implementation as well.

Specified by:
clearCachedData in interface IEngineServiceView
Since:
1.0.1

setLocale

public void setLocale(java.util.Locale value)
Changes the locale for the engine.

Specified by:
setLocale in interface org.apache.tapestry.IEngine

setupForRequest

protected void setupForRequest(org.apache.tapestry.request.RequestContext context)
Invoked from service(RequestContext) 55 to ensure that the engine's instance variables are setup. This allows the application a chance to restore transient variables that will not have survived deserialization. Determines the servlet prefix: this is the base URL used by servicesto build URLs. It consists of two parts: the context path and the servlet path.

The servlet path is retrieved from HttpServletRequest.getServletPath()>HttpServletRequest.getServletPath() 55 .

The context path is retrieved from HttpServletRequest.getContextPath()>HttpServletRequest.getContextPath() 55 .

The global object is retrieved from IEngine.getGlobal()>IEngine.getGlobal() 55 method.

The final path is available via the getServletPath() 55 method.

In addition, this method locates and/or creates the:

This order is important, because some of the later shared objects depend on some of the earlier shared objects already having been located or created (especially pool 55 ).

Subclasses should invoke this implementation first, then perform their own setup.

getClassResolver

public org.apache.hivemind.ClassResolver getClassResolver()
Description copied from interface: org.apache.tapestry.IEngine
Returns an object that can resolve resources and classes.

Specified by:
getClassResolver in interface org.apache.tapestry.IEngine

toString

public java.lang.String toString()
Generates a description of the instance. Invokes extendDescription(ToStringBuilder) 55 to fill in details about the instance.

isResetServiceEnabled

public boolean isResetServiceEnabled()
Returns true if the reset service is curently enabled.

Specified by:
isResetServiceEnabled in interface org.apache.tapestry.IEngine

getActivePageNames

public abstract java.util.Collection getActivePageNames()
Implemented by subclasses to return the names of the active pages (pages for which recorders exist). May return the empty list, but should not return null.

getVisit

public java.lang.Object getVisit()
Gets the visit object, if it has been created already.

If the visit is non-null then the isDirty() 55 flag is set (because the engine can't tell what the caller will do with the visit).

Specified by:
getVisit in interface org.apache.tapestry.IEngine

getVisit

public java.lang.Object getVisit(org.apache.tapestry.IRequestCycle cycle)
Gets the visit object, invoking createVisit(IRequestCycle) 55 to create it lazily if needed. If cycle is null, the visit will not be lazily created.

After creating the visit, but before returning, the javax.servlet.http.HttpSessionwill be created, and setStateful() 55 will be invoked.

Sets the isDirty() 55 flag, if the return value is not null.

Specified by:
getVisit in interface org.apache.tapestry.IEngine

setVisit

public void setVisit(java.lang.Object value)
Updates the visit object and sets the dirty flag 55 .

Specified by:
setVisit in interface org.apache.tapestry.IEngine

getHasVisit

public boolean getHasVisit()

createVisit

protected java.lang.Object createVisit(org.apache.tapestry.IRequestCycle cycle)
Invoked to lazily create a new visit object when it is first referenced (by getVisit(IRequestCycle) 55 ). This implementation works by looking up the name of the class to instantiate in the configuration 55 .

Subclasses may want to overide this method if some other means of instantiating a visit object is required.

getGlobal

public java.lang.Object getGlobal()
Returns the global object for the application. The global object is created at the start of the request (setupForRequest(RequestContext) 55 invokes createGlobal(RequestContext) 55 if needed), and is stored into the javax.servlet.ServletContext. All instances of the engine for the application share the global object; however, the global object is explicitly not replicated to other servers within a cluster.

Specified by:
getGlobal in interface org.apache.tapestry.IEngine
Since:
2.3

getScriptSource

public IScriptSource getScriptSource()
Description copied from interface: org.apache.tapestry.IEngine
Returns a source for parsed org.apache.tapestry.IScripts. The source is shared between all sessions.

Specified by:
getScriptSource in interface org.apache.tapestry.IEngine

isStateful

public boolean isStateful()
Description copied from interface: org.apache.tapestry.IEngine
Returns true if the engine has state and, therefore, should be stored in the HttpSession. This starts as false, but becomes true when the engine requires state (such as when a visit object is created, or when a peristent page property is set).

Specified by:
isStateful in interface org.apache.tapestry.IEngine

setStateful

protected void setStateful()
Invoked by subclasses to indicate that some state must now be stored in the engine (and that the engine should now be stored in the HttpSession). The caller is responsible for actually creating the HttpSession (it will have access to the org.apache.tapestry.request.RequestContext).

Since:
1.0.2

getListeners

public org.apache.tapestry.listener.ListenerMap getListeners()
Allows subclasses to include listener methods easily.

Since:
1.0.2

handleRedirectException

protected void handleRedirectException(org.apache.tapestry.IRequestCycle cycle,
                                       org.apache.tapestry.RedirectException ex)
Invoked when a org.apache.tapestry.RedirectExceptionis thrown during the processing of a request.

Since:
2.2

getComponentMessagesSource

public org.apache.tapestry.services.ComponentMessagesSource getComponentMessagesSource()
Description copied from interface: org.apache.tapestry.IEngine
Returns a shared object that allows components to find their set of localized strings.

Specified by:
getComponentMessagesSource in interface org.apache.tapestry.IEngine
Since:
2.0.4

getDataSqueezer

public org.apache.tapestry.services.DataSqueezer getDataSqueezer()
Description copied from interface: org.apache.tapestry.IEngine
Returns a shared instance of org.apache.tapestry.util.io.DataSqueezerImpl.

Specified by:
getDataSqueezer in interface org.apache.tapestry.IEngine

extractServiceName

protected java.lang.String extractServiceName(org.apache.tapestry.request.RequestContext context)
Invoked from service(RequestContext) 55 to extract, from the URL, the name of the service. The current implementation expects the first pathInfo element to be the service name. At some point in the future, the method of constructing and parsing URLs may be abstracted into a developer-selected class.

Subclasses may override this method if the application defines specific services with unusual URL encoding rules.

This implementation simply extracts the value for query parameter Tapestry.SERVICE_QUERY_PARAMETER_NAME>Tapestry.SERVICE_QUERY_PARAMETER_NAME 55 and extracts the service name from that.

For supporting the JSP tags, this method first checks for attribute Tapestry.TAG_SUPPORT_SERVICE_ATTRIBUTE>Tapestry.TAG_SUPPORT_SERVICE_ATTRIBUTE 55 . If non-null, then Tapestry.TAGSUPPORT_SERVICE>Tapestry.TAGSUPPORT_SERVICE 55 is returned.

Since:
2.2

getPropertySource

public IPropertySource getPropertySource()
Description copied from interface: org.apache.tapestry.IEngine
Returns a IPropertySource that should be used to obtain configuration data. The returned source represents a search path that includes (at a minimum):
  • Properties of the org.apache.tapestry.spec.ApplicationSpecification
  • Initial Parameters of servlet (configured in the web.xml deployment descriptor)
  • Initial Parameter of the servlet context (also configured in web.xml)
  • System properties (defined with the -D JVM command line parameter)
  • Hard-coded "factory defaults" (for some properties)

Specified by:
getPropertySource in interface org.apache.tapestry.IEngine
Since:
2.3

getExceptionPageName

protected java.lang.String getExceptionPageName()
Since:
3.0

getStaleLinkPageName

protected java.lang.String getStaleLinkPageName()
Since:
3.0

getStaleSessionPageName

protected java.lang.String getStaleSessionPageName()
Since:
3.0

createGlobal

protected java.lang.Object createGlobal(org.apache.tapestry.request.RequestContext context)
Creates the shared Global object. This implementation looks for an configuration property, org.apache.tapestry.global-class, and instantiates that class using a no-arguments constructor. If the property is not defined, a synchronized java.util.HashMapis created.

Since:
2.3

getPool

public org.apache.tapestry.services.ObjectPool getPool()
Description copied from interface: org.apache.tapestry.IEngine
Returns a org.apache.tapestry.util.pool.Pool that is used to store all manner of objects that are needed throughout the system. This is the best way to deal with objects that are both expensive to create and not threadsafe. The reset service will clear out this Pool.

Specified by:
getPool in interface org.apache.tapestry.IEngine

getComponentClassEnhancer

public IComponentClassEnhancer getComponentClassEnhancer()
Description copied from interface: org.apache.tapestry.IEngine
Returns an object that can create enhanced versions of component classes.

Specified by:
getComponentClassEnhancer in interface org.apache.tapestry.IEngine

isDirty

public boolean isDirty()
Returns true if the engine has (potentially) changed state since the last time it was stored into the javax.servlet.http.HttpSession. Various events set this property to true.

Since:
3.0

markDirty

protected void markDirty()
Invoked to set the dirty flag, indicating that the engine should be stored into the javax.servlet.http.HttpSession.

Since:
3.0

valueBound

public void valueBound(javax.servlet.http.HttpSessionBindingEvent arg0)
Clears the dirty flag when a engine is stored into the javax.servlet.http.HttpSession.

Specified by:
valueBound in interface javax.servlet.http.HttpSessionBindingListener
Since:
3.0

valueUnbound

public void valueUnbound(javax.servlet.http.HttpSessionBindingEvent arg0)
Does nothing.

Specified by:
valueUnbound in interface javax.servlet.http.HttpSessionBindingListener
Since:
3.0

getDefaultOutputEncoding

protected java.lang.String getDefaultOutputEncoding()
The encoding to be used if none has been defined using the output encoding property. Override this method to change the default.

Since:
3.0

getOutputEncoding

public java.lang.String getOutputEncoding()
Returns the encoding to be used to generate the servlet responses and accept the servlet requests. The encoding is defined using the org.apache.tapestry.output-encoding and is UTF-8 by default

Specified by:
getOutputEncoding in interface org.apache.tapestry.IEngine
Since:
3.0
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