nextapp.echoservlet
Class Connection

java.lang.Object
  nextapp.echoservlet.Connection

public final class Connection

extends java.lang.Object

A wrapper that holds information about an HTTP request, provides facilities to generate a response, and provides access to the application instance that is to process it.

Field Summary

private static java.lang.String	CACHE_MAX_AGE A convenience for setting the cache header
private boolean	debugInteractiveController A flag that indicates whether the interactivecontroller frame should be made visible and provide debugging information.
private boolean	debugOptionsEnabled A flag that indicates whether any debug options may be enabled.
private boolean	debugPerformanceLogging A flag that indicates whether the time interval during which each request is processed will be recorded.
private boolean	debugVerboseLogging A flag indicating verbose logging.
private static java.lang.String	INSTANCE_PEER_SESSION_KEY_PREFIX The prefix that will be used to determine the key name under which the application will be stored in HttpSession.
private InstancePeer	instancePeer Reference to the application's InstancePeer, may be null under initialization conditions.
private java.lang.String	instancePeerSessionKey The session key with holds the instance peer as its value.
private static long	lastFreeMemory The amount of free memory available.
private javax.servlet.http.HttpServletRequest	request Reference to the HTTP request object wrapped by this Connection.
private javax.servlet.http.HttpServletResponse	response Reference to the HTTP response object wrapped by this Connection.
private EchoServer	server Reference to the EchoServer.
private static int	serviceNumber A global counter of services invoked for the life of the VM.
private ServletEncodingAdapter	servletEncodingAdapter Reference to servlet encoding adapter.
private VariableData	variableData Holds the VariableData object associated with this Connection.

Constructor Summary

(package private)

Connection(EchoServer server, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Creates a connection object that will handle the given request and response.

Method Summary

java.lang.String	correctUri(java.lang.String uri) Corrects relative-path URIs to include the application name, such that they can properly retrieve the desired resource.
java.lang.String	getApplicationUri() Returns the URI of the application.
java.lang.String	getCacheIdPrefix() Returns a prefix to prepend to cache ids in order to ensure that incorrect cached resources are used by client in the event either the server or the users session has restarted.
Id	getIdParameter(java.lang.String name) Returns the specified request parameter as an Id value.
InstancePeer	getInstancePeer() Returns the InstancePeer associated with this connection.
java.io.OutputStream	getOutputStream() Returns the OutputStream object that may be used to generate a response.
java.lang.String	getParameter(java.lang.String name) Returns the value of the HTTP parameter associated with the given name.
java.util.Enumeration	getParameterNames() Returns an enumeration of all parameter names passed in the request.
javax.servlet.http.HttpServletRequest	getRequest() Returns the HttpServletRequest wrapped by this Connection.
javax.servlet.http.HttpServletResponse	getResponse() Returns the HttpServletResponse wrapped by this Connection.
EchoServer	getServer() Returns the EchoServer wrapped by this Connection.
VariableData	getVariableData() Returns the VariableData associated with this Connection.
java.io.PrintWriter	getWriter() Returns the PrintWriter object that may be used to generate a response.
(package private) boolean	isDebugInteractiveControllerEnabled() Returns true if the interactive controller debug feature is enabled.
(package private) boolean	isDebugVerboseLoggingEnabled() Returns true if the verbose logging debug feature is enabled.
(package private) void	process() Retrieves and executes the appropriate Service requested by the client browser.
private Service	retrieveService(Id id) Returns the service that corresponds to the specified Id.
void	setContentType(ContentType contentType) Sets the content type of the response.
(package private) void	setInstancePeer(InstancePeer instancePeer) Sets the InstancePeer that has been created for the user making this request.
(package private) void	unbindInstancePeer() Unbinds the application's InstancePeer from the session.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

INSTANCE_PEER_SESSION_KEY_PREFIX

private static final java.lang.String INSTANCE_PEER_SESSION_KEY_PREFIX

The prefix that will be used to determine the key name under which the application will be stored in HttpSession. The application's URI will be appended to the session prefix to form a unique value.

See Also:

Constant Field Values

CACHE_MAX_AGE

private static final java.lang.String CACHE_MAX_AGE

A convenience for setting the cache header

See Also:

Constant Field Values

lastFreeMemory

private static long lastFreeMemory

The amount of free memory available. Used for performance testing purposes.

serviceNumber

private static int serviceNumber

A global counter of services invoked for the life of the VM. Useful only for debugging purposes.

request

private javax.servlet.http.HttpServletRequest request

Reference to the HTTP request object wrapped by this Connection.

response

private javax.servlet.http.HttpServletResponse response

Reference to the HTTP response object wrapped by this Connection.

instancePeer

private InstancePeer instancePeer

Reference to the application's InstancePeer, may be null under initialization conditions.

server

private EchoServer server

Reference to the EchoServer.

servletEncodingAdapter

private ServletEncodingAdapter servletEncodingAdapter

Reference to servlet encoding adapter.

variableData

private VariableData variableData

Holds the VariableData object associated with this Connection.

instancePeerSessionKey

private java.lang.String instancePeerSessionKey

The session key with holds the instance peer as its value.

debugOptionsEnabled

private boolean debugOptionsEnabled

A flag that indicates whether any debug options may be enabled. Debug options work only if this flag is set.

debugPerformanceLogging

private boolean debugPerformanceLogging

A flag that indicates whether the time interval during which each request is processed will be recorded. Note: the logged time is not the time required to service a particular request, as multiple requests may be processed simultaneously.

debugInteractiveController

private boolean debugInteractiveController

A flag that indicates whether the interactivecontroller frame should be made visible and provide debugging information.

debugVerboseLogging

private boolean debugVerboseLogging

A flag indicating verbose logging. Enable to see a great deal of debugging information.

Constructor Detail

Connection

Connection(EchoServer server,
           javax.servlet.http.HttpServletRequest request,
           javax.servlet.http.HttpServletResponse response)
     throws java.io.IOException,
            javax.servlet.ServletException

Creates a connection object that will handle the given request and response. The InstancePeer will be pulled from the session if one exists. A session will NOT be created if one does not exist.

Parameters:

server - The EchoServer generating the connection.

request - The HTTP request object that was passed to the servlet.

response - The HTTP response object that was passed to the servlet.

Method Detail

getApplicationUri

public java.lang.String getApplicationUri()

Returns the URI of the application.

Returns:

The URI of the application.

getCacheIdPrefix

public java.lang.String getCacheIdPrefix()

Returns a prefix to prepend to cache ids in order to ensure that incorrect cached resources are used by client in the event either the server or the users session has restarted. Returns an empty string if no InstancePeer has been created, otherwise defers responsibility to the InstancePeer.

Returns:

A prefix to prepend to cache ids to make them unique across server and session restarts.

getIdParameter

public Id getIdParameter(java.lang.String name)

Returns the specified request parameter as an Id value. If the parameter is was not provided in the request, or if the parameter is not a valid Id value, null is returned.

Parameters:

name - The parameter name.

Returns:

The parameter as an Id.

getInstancePeer

public InstancePeer getInstancePeer()

Returns the InstancePeer associated with this connection. If the session has not been initialized, null is returned.

Returns:

The InstancePeer associated with this connection.

getOutputStream

public java.io.OutputStream getOutputStream()

Returns the OutputStream object that may be used to generate a response. This method may be called once. If it is called, the getWriter() method may not be called. This method wraps a call to HttpServletResponse.getOutputStream(). The OutputStream will be closed by the servlet container.

Returns:

the OutputStream object that may be used to generate a response to the client.

getParameter

public java.lang.String getParameter(java.lang.String name)

Returns the value of the HTTP parameter associated with the given name.

Parameters:

name - The name of the parameter to return.

Returns:

The value of the HTTP parameter associated with the given name.

getParameterNames

public java.util.Enumeration getParameterNames()

Returns an enumeration of all parameter names passed in the request.

Returns:

An enumeration of all parameter names passed in the request.

getRequest

public javax.servlet.http.HttpServletRequest getRequest()

Returns the HttpServletRequest wrapped by this Connection.

Returns:

The HttpServletRequest wrapped by this Connection.

getResponse

public javax.servlet.http.HttpServletResponse getResponse()

Returns the HttpServletResponse wrapped by this Connection.

Returns:

The HttpServletResponse wrapped by this Connection.

getServer

public EchoServer getServer()

Returns the EchoServer wrapped by this Connection.

Returns:

The EchoServer wrapped by this Connection.

getVariableData

public VariableData getVariableData()

Returns the VariableData associated with this Connection. If an InstancePeer exists, its VariableData is returned, otherwise, a temporary VariableData object is returned that contains defaults used for initialization.

Returns:

The VariableData object associated with this Connection.

getWriter

public java.io.PrintWriter getWriter()

Returns the PrintWriter object that may be used to generate a response. This method may be called once. If it is called, the getOuputStream() method may not be called. This method wraps a call to HttpServletResponse.getWriter(). The PrintWriter will be closed by the servlet container.

Returns:

the PrintWriter object that may be used to generate a response to the client.

correctUri

public java.lang.String correctUri(java.lang.String uri)

Corrects relative-path URIs to include the application name, such that they can properly retrieve the desired resource.

Parameters:

uri - The URI to correct.

Returns:

The corrected URI.

isDebugInteractiveControllerEnabled

boolean isDebugInteractiveControllerEnabled()

Returns true if the interactive controller debug feature is enabled.

Returns:

True if the interactive controller debug feature is enabled.

isDebugVerboseLoggingEnabled

boolean isDebugVerboseLoggingEnabled()

Returns true if the verbose logging debug feature is enabled.

Returns:

True if the verbose logging debug feature is enabled.

process

void process()
       throws java.io.IOException

Retrieves and executes the appropriate Service requested by the client browser. Sets cache control HTTP headers for the response. If the user does not yet have an InstancePeer, then initialization services are executed. Logs debugging information if necessary.

Throws:

java.io.IOException

retrieveService

private Service retrieveService(Id id)

Returns the service that corresponds to the specified Id.

Parameters:

id - The id of the service to return.

Returns:

The service corresponding to the specified Id.

setContentType

public void setContentType(ContentType contentType)

Sets the content type of the response. This method will automatically append a character encoding to non-binary content types.

Parameters:

contentType - The content type of the response.

setInstancePeer

void setInstancePeer(InstancePeer instancePeer)

Sets the InstancePeer that has been created for the user making this request. This method is called once, by the Initializer.

Parameters:

instancePeer - The InstancePeer that will be used by this user.

unbindInstancePeer

void unbindInstancePeer()

Unbinds the application's InstancePeer from the session. This terminates the application. If the user visits the application's URI again, a new InstancePeer will be created.