wt.httpgw
Class HTTPResponse

java.lang.Object
  wt.httpgw.HTTPResponse

Direct Known Subclasses:

FlaggedHTTPResponse, GZIPHTTPResponse, HTTPResponseImpl, HTTPServletResponse, ReconnectedHTTPResp

public abstract class HTTPResponse

extends Object

This class is a carrier of HTTP response information back to an HTTP gateway from a method server. It uses customized serialization code to stream response bodies to the gateway.

Server-side Serialization The server (NetFactor method server) constructs response objects to carry response information back to the gateway. The object contains fields to store response header information, an output stream reference, and a target class and method.

Object serialization stores the RMI marshal stream reference in the object and invokes the target method using Java's reflection API. The target method uses methods on the response object to set response attributes (content-type, status, etc.) and eventually calls a method to retrieve the output stream on which to write the response body. This call causes the response attributes to be written to the marshal stream. When the target method returns, serialization is complete.

Client-side Deserialization The client (HTTP gateway) receives the response object as the return value of a RMI call. It is deserialized before the RMI call completes. In order to support processing of streamed data, the deserialization code looks up the corresponding HTTPGateway object and uses it to send the response directly from the deserialization code.

First the headers are set on the real gateway response, then the content body is forwarded by reading blocks of data from the input stream and writing them to real response output stream until the entire body has been sent.

  Note: Four response headers are set by default:
        Protocol is set to HTTP/1.0;
        Status is set to 200 (OK); and
        Content-Type is set to text/html.
        Expires is set to long ago, the Java epoch - date(0)

        If you need to set other headers or change these defaults,
        you must do so in your response processing PRIOR to calling
        getOutputStream.
 

Supported API: true
Extendable: false

Field Summary

Throwable	respException Exception caught unmarshalling or invoking target method
(package private) static long	serialVersionUID

Constructor Summary

HTTPResponse()

Method Summary

abstract boolean	containsHeader(String s) Checks if the response header is present.
abstract Object	get(String s) Gets the value of this response header key.
abstract OutputStream	getOutputStream() Called to get the output stream to write the data to.
abstract Enumeration	keys() Gets the response header keys.
abstract void	setDateHeader(String s1, long date) Sets a date type response header.
abstract void	setHeader(String s1, String s2) Sets a string type response header.
abstract void	setIntHeader(String s1, int v1) Sets a int type response header.
abstract void	setRemoteHost(String remote_host) Setter for the remote host that will be displayed in exception tracebacks.
abstract void	setRespTarget(Method method, Object[] args) Setter for the target method that will generate the real response to the output stream.
abstract void	setStatus(int v1) Sets a simple Status response header.
abstract void	setStatus(int v1, String s1) Sets a Status response header.

Methods inherited from class java.lang.Object

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

Field Detail

respException

public transient Throwable respException

Exception caught unmarshalling or invoking target method

serialVersionUID

static final long serialVersionUID

See Also:

Constant Field Values

Constructor Detail

HTTPResponse

public HTTPResponse()

Method Detail

getOutputStream

public abstract OutputStream getOutputStream()
                                      throws IOException

Called to get the output stream to write the data to. It also causes the HTTPResponseHeaders object to be written out to the RMI marshal stream.

Supported API: true

Returns:

OutputStream for writing response body

Throws:

IOException - if not marshaling response in writeObject. the output stream is null until such time. Also, if the response target class or method is null. There is not a proper business class or method to write the response.

setRespTarget

public abstract void setRespTarget(Method method,
                                   Object[] args)

Setter for the target method that will generate the real response to the output stream.

Supported API: false

Parameters:

method - is the target business Method

args - are the object array of arguments needed my the target method.

setRemoteHost

public abstract void setRemoteHost(String remote_host)

Setter for the remote host that will be displayed in exception tracebacks.

Supported API: false

containsHeader

public abstract boolean containsHeader(String s)

Checks if the response header is present.

Supported API: true

Parameters:

s - String the header to search for.

Returns:

A boolean if the header is set.

keys

public abstract Enumeration keys()

Gets the response header keys.

Supported API: false

Returns:

An Enumeration of the header keys.

get

public abstract Object get(String s)

Gets the value of this response header key.

Supported API: false

Parameters:

s - the key, as a string, to get the value of.

Returns:

the value of this key as an Object.

setHeader

public abstract void setHeader(String s1,
                               String s2)

Sets a string type response header.

Supported API: true

Parameters:

s1 - String name of the header

s2 - String value to which header is set

setDateHeader

public abstract void setDateHeader(String s1,
                                   long date)

Sets a date type response header.

Supported API: true

Parameters:

s1 - String name of the header

date - long value to which header is set value is milliseconds since the epoch.

setIntHeader

public abstract void setIntHeader(String s1,
                                  int v1)

Sets a int type response header.

Supported API: true

Parameters:

s1 - String name of the header

v1 - int value to which header is set

setStatus

public abstract void setStatus(int v1)

Sets a simple Status response header.

Supported API: true

Parameters:

v1 - Integer Status code

setStatus

public abstract void setStatus(int v1,
                               String s1)

Sets a Status response header.

Supported API: true

Parameters:

v1 - Integer Status code

s1 - String Status reason code