ORG.oclc.webz
Class ImageFETCH

java.lang.Object
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  +--ORG.oclc.webz.Verb
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        +--ORG.oclc.webz.ZVerb
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              +--ORG.oclc.webz.FETCH
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                    +--ORG.oclc.webz.ImageFETCH

public class ImageFETCH

extends FETCH

The ImageFETCH class is the WebZ Verb that is specialized to perform Z39.50 present requests for binary images stored in a newton database. ImageFETCH uses input parameters contained in a RequestManager object, or a RequestManager object and a string containing a URL. A successful execution of ImageFETCH creates an HTTP response containing the binary image with the appropriate HTTP headers. If a failure occurs, occurs, the user variables code and msg are updated to contain the reason and the bad page or command for execution is set up in the RequestManager.

The processing flow of the ImageFETCH class is to initialize the user for Z39.50 activity, parse the URL input parameters to generate the appropriate Z39.50 present request, create and send the present, create the appropriate HTTP response for the binary data, and set up the HTTP response in the RequestManager object for delivery to the browser. If the image data returned is a GIF, appropriate conversion to TIFF format is done.

The URL widgets recognized by the ImageFETCH class are:
resultsetname - the resultset to present records from
numrecs - the number of records to retrieve
recno - the record number of the record to retrieve
item - the item number(page) within the record to retrieve
scale - for gif data, the scale to size the tiff response to: where valid scales are: 2, 3, 4, 6, 25 where 2 is the largest.
bad - the failure command or page to process

The user state entities that are set as a result of the present are:
displaydbname - the database name corresponding the database records returned from the present
longdisplaydbname - the longname of the displaydbname database
numrecs - the number of records requested
returnednumrecs - the number of records returned
recno - the record number for a multi-record request
fullrecno - the record number for a format=F request
code - the status of the present - see WebZErrors
msg - the error message for the present
zcode - the Z39.50 error code - see Diagnostic1
zmsg - the Z39.50 error message

See Also:

ImageInfo, FailurePage, RequestManager, JavaPage, UserStateObject, ZDb, ZServer, ZUserData, Z39present

Fields inherited from class ORG.oclc.webz.ZVerb

bytesIn, bytesOut, dbGroupSearch, dbname, fmtClass, format, inputQueryInfo, numrecs, postings, ranked, recno, resultSetName, sorting, tempDb, traceMsgs, z39session, zDb, zQueryTerm, zServer, zUserData

Fields inherited from class ORG.oclc.webz.Verb

user, widgets

Constructor Summary

ImageFETCH()
Constructs an ImageFETCH object.

Method Summary

protected void	doPresent() Issues the Z39.50 present request for the image database records.
protected void	parseParms()
void	runit(RequestManager rMngr) Executes the ImageFETCH class using the parameters in the RequestManager object.
void	runit(RequestManager rMngr, String URLCmd) Executes the ImageFETCH class using the RequestManager object and the input parameters contained in the URLCmd.

Methods inherited from class ORG.oclc.webz.ZVerb

doAccessControl, doSort, initZUser, restoreDbState, saveDbState, saveRecs, toString

Methods inherited from class ORG.oclc.webz.Verb

setUpPage

Methods inherited from class java.lang.Object

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

Constructor Detail

ImageFETCH

public ImageFETCH()

Constructs an ImageFETCH object.

Method Detail

runit

public void runit(RequestManager rMngr)

Executes the ImageFETCH class using the parameters in the RequestManager object. Each method called from the runit() method can throw a FailurePage exception. If this occurs, the catch logic for the exceptions invokes setup of the bad page or command to execute upon return. If the request is successfully executed, the HTTP Response is set up in the RequestManager object.

Parameters:

rMngr - the RequestManager object

Overrides:

runit in class FETCH

runit

public void runit(RequestManager rMngr,
                  String URLCmd)

Executes the ImageFETCH class using the RequestManager object and the input parameters contained in the URLCmd. This would be used when creating an imageFETCH object from one of the application classes. Each method called from the runit() method can throw a FailurePage exception. If this occurs, the catch logic for the exceptions invokes setup of the bad page or command to execute upon return. If the request is successfully executed, the HTTP Response is set up in the RequestManager object.

Parameters:

rMngr - the RequestManager object

URLCmd - the command string with the widgets delimited by ":" For example, ImageFETCH:resultset=1:item=5:scale=3

Overrides:

runit in class FETCH

parseParms

protected void parseParms()
                   throws FailurePage

Overrides:

parseParms in class FETCH

doPresent

protected void doPresent()
                  throws FailurePage

Issues the Z39.50 present request for the image database records.

Throws:

FailurePage - unable to issue the Z39.50 Present or the Present request returned an error.

Overrides:

doPresent in class FETCH