com.webobjects.appserver
Class WOResponse

java.lang.Object
  |
  +--com.webobjects.appserver.WOMessage
        |
        +--com.webobjects.appserver.WOResponse

All Implemented Interfaces:

Cloneable, NSKeyValueCoding, NSKeyValueCoding.ErrorHandling, NSKeyValueCodingAdditions, WOActionResults

public class WOResponse

extends WOMessage

implements WOActionResults, Cloneable

A WOResponse object represents an HTTP response that an application returns to a Web server to complete a cycle of the request-response loop. The composition of a response occurs during the third and final phase of this loop, a phase marked by the propagation of the appendToResponse method through the objects of the application. The WOApplication object first invokes this method, passing in a newly-created WOResponse object as an argument. WOElement objects, which represent the dynamic and static HTML elements on a page, respond to the method by appending their HTML representation to the content of the WOResponse object. WOApplication, WOSession, and WOComponent objects can also respond to the method by adding information to the WOResponse object.

A WOResponse has two major parts: HTML content and HTTP information. The HTML content is what is displayed in a Web browser; it can include escaped HTML, which is HTML code shown "as is," uninterpreted. The HTTP information encapsulated by a WOResponse object is used when handling the response. This HTTP data includes headers, status codes, and an HTTP version string.

The WOMessage class -- from which WOResponse inherits -- declares most of the methods you use when constructing a response. These methods can be divided into two groups, those that add to a response's HTML content and those that read and set HTTP information. For images and other binary data, the user should use the method appendContentData declared in the WOMessage class. You can obtain and set the entire content of the message using WOResponse's content and setContent methods. The following example shows a sequence of appendContent invocations that compose an HTTP "POST" message:

 aResponse.appendContentString("<form method=\"POST \"action=\"");
 aResponse.appendContentHTMLAttributeValue(aContext.url());
 aResponse.appendContentCharacter('"');
 aResponse.appendContentString(">");
 

It is possible to set an InputStream as the content of the response as well, by invoking setContentStream. If setContentStream is invoked with a non-null InputStream, only the data in the InputStream will be returned to the client - any other content (set using the WOMessage APIs) will be ignored.

See Also:

WOMessage.appendContentData(NSData dataObject), WOMessage.setContent(NSData someData), WOMessage.content(), WOMessage, setContentStream(InputStream, int, int)

Nested Class Summary

Nested classes inherited from class com.webobjects.foundation.NSKeyValueCoding

NSKeyValueCoding.DefaultImplementation, NSKeyValueCoding.ErrorHandling, NSKeyValueCoding.Null, NSKeyValueCoding.UnknownKeyException, NSKeyValueCoding.Utility, NSKeyValueCoding.ValueAccessor

Nested classes inherited from class com.webobjects.foundation.NSKeyValueCodingAdditions

NSKeyValueCodingAdditions.DefaultImplementation, NSKeyValueCodingAdditions.Utility

Field Summary

Fields inherited from class com.webobjects.appserver.WOMessage

HTTP_STATUS_FORBIDDEN, HTTP_STATUS_FOUND, HTTP_STATUS_INTERNAL_ERROR, HTTP_STATUS_MOVED_PERMANENTLY, HTTP_STATUS_NO_CONTENT, HTTP_STATUS_NOT_FOUND, HTTP_STATUS_OK, TheDefaultResponseEncoding

Fields inherited from interface com.webobjects.foundation.NSKeyValueCoding

NullValue

Fields inherited from interface com.webobjects.foundation.NSKeyValueCodingAdditions

KeyPathSeparator

Constructor Summary

WOResponse()
Creates a WOResponse with HTTP status set to 200 (OK), client caching enabled, and the default string encoding set to ISO Latin 1.

Method Summary

Object	clone()
InputStream	contentInputStream() Returns the InputStream set in setContentStream.
int	contentInputStreamBufferSize() Returns the size of the transfer buffer set in setContentStream.
int	contentInputStreamLength() Returns the length of the content set in setContentStream.
void	disableClientCaching() Appends certain headers to the response to disable caching in the client (browser).
WOResponse	generateResponse() WOResponse's implementation simply returns itself.
void	setContentStream(InputStream inputStream, int bufferSize, int contentSize) This sets an InputStream as the source of the response content (rather than a String or an NSData).
void	setStatus(int aStatus) Sets the HTTP status to aStatus.
int	status() Returns the HTTP return status of the WOResponse.
String	toString() Returns a String representation of the receiver.

Methods inherited from class com.webobjects.appserver.WOMessage

addCookie, appendContentCharacter, appendContentData, appendContentDOMDocumentFragment, appendContentHTMLAttributeValue, appendContentHTMLString, appendContentString, appendHeader, appendHeaders, canAccessFieldsDirectly, content, contentAsDOMDocument, contentEncoding, contentString, cookies, defaultEncoding, defaultURLEncoding, equals, handleQueryWithUnboundKey, handleTakeValueForUnboundKey, headerForKey, headerKeys, headers, headersForKey, httpVersion, removeCookie, removeHeadersForKey, requiresHTMLEscaping, setContent, setContent, setContent, setContentDOMDocument, setContentEncoding, setDefaultEncoding, setDefaultURLEncoding, setHeader, setHeaders, setHeaders, setHTTPVersion, setUserInfo, stringByEscapingHTMLAttributeValue, stringByEscapingHTMLString, takeValueForKey, takeValueForKeyPath, unableToSetNullForKey, userInfo, valueForKey, valueForKeyPath

Methods inherited from class java.lang.Object

finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

WOResponse

public WOResponse()

Creates a WOResponse with HTTP status set to 200 (OK), client caching enabled, and the default string encoding set to ISO Latin 1.

Method Detail

clone

public Object clone()

Overrides:

clone in class WOMessage

contentInputStream

public InputStream contentInputStream()

Returns the InputStream set in setContentStream. If not stream was set, it returns null.

Returns:

InputStream the source of the response content, or null.

See Also:

setContentSize(InputStream, int, int), contentInputStreamBufferSize(), contentInputStreamLength()

contentInputStreamBufferSize

public int contentInputStreamBufferSize()

Returns the size of the transfer buffer set in setContentStream.

Returns:

int the size of the transfer buffer.

See Also:

setContentSize(InputStream, int, int), contentInputStream(), contentInputStreamLength()

contentInputStreamLength

public int contentInputStreamLength()

Returns the length of the content set in setContentStream.

Returns:

int the size of the response content.

See Also:

setContentSize(InputStream, int, int), contentInputStreamBufferSize(), contentInputStream()

disableClientCaching

public void disableClientCaching()

Appends certain headers to the response to disable caching in the client (browser). Do not invoke this method more than once for a given response. After this method is invoked, the response will include the following headers:

• date:
• expires:
• pragma: no-cache

If cache-control headers are allowed (if the WOAllowsCacheControlHeader property is set to true, which is the default behavior), the response also includes the following cache-control headers:

• private
• no-cache
• no-store
• must-revalidate
• max-age=0

generateResponse

public WOResponse generateResponse()

WOResponse's implementation simply returns itself.

Specified by:

generateResponse in interface WOActionResults

Returns:

a WOResponse object

See Also:

WOComponent.generateResponse()

setContentStream

public void setContentStream(InputStream inputStream,
                             int bufferSize,
                             int contentSize)

This sets an InputStream as the source of the response content (rather than a String or an NSData). When the response is returned to the client, the data is streamed from inputStream, using bufferSize as the size of the transport buffer in bytes. Note that the contentSize (also in bytes) must be accurate.

If there is an InputStream available when the response is to be returned, only the data in the InputStream is returned -- any data that was added or set (either as String or NSData) is ignored.
The InputStream will be closed after the response is returned to the client, or if an exception is thrown while sending the response. If you want custom logic to be invoked at that point, create a custom FilterInputStream to wrap the InputStream source and override the close method. However, note that the close() will be invoked after the entire request-response loop has finished; thus references to resources that need to be cleaned up must be carefully managed. Also be cautious during the clean-up itself, as some resources may have changed state. For instance, the defaultEditingContext of a session may have already been unlocked.

Parameters:

inputStream - is the source of the response content.

bufferSize - is the size of the buffer to use when streaming the content. Defaults to 4096.

contentSize - is the size of the content in bytes.

See Also:

contentInputStream(), contentInputStreamBufferSize(), contentInputStreamLength()

setStatus

public void setStatus(int aStatus)

Sets the HTTP status to aStatus. The most commonly useful status codes are defined in static fields on WOMessage.

Consult RFC 2616 for the significance of status integers.

Parameters:

aStatus - the integer stating the status of the HTTP

See Also:

status(), WOMessage

status

public int status()

Returns the HTTP return status of the WOResponse. The most commonly useful status codes are defined in static fields on WOMessage.

By default, the status is 200 ("OK" status).

Consult RFC 2616 for the significance of status integers.

Returns:

an integer code representing the HTTP status

See Also:

setStatus(int aStatus), WOMessage

toString

public String toString()

Returns a String representation of the receiver. This string representation is suitable for debugging. It details many of the WOResponse object's attributes and should not be confused with the contentString method.

Overrides:

toString in class WOMessage

Returns:

String representation of the receiver