source: TI02-CSML/trunk/csml/csmllibs/csmlxlink.py @ 2040

'''csmlxlink - contains functions used for processin xlinks in csml documents.
created 23 01 2007 by Dominic Lowe, CCLRC, BADC
'''

import sys
import csml

def createXlinks(dataset):
    '''returns a CSMLStorageDescriptor with any fileLists reduced to xlinks to other fileLists where possible.
    e.g if 3 features share the same fileList, the fileList will be explicit in the first feature, and referenced only by xlink from the second 2 features. 
    This function compares the fileLists of all AggregatedArrays  in the CSMLStorageDescriptor and looks for matching fileLists'''
    ds=dataset
    if not hasattr(ds, 'storageDescriptor'):
        return None
    else:
        #xlinkDictionary = {axislabel_axisspanned :(values, gmlid), .... }
        #process:
        #go through each ordinate in each domain for each feature.
        #if ordinate (exact match with labels, span + value) is not in dictionary add it
        #and create a new gml id.
        #else if it is in the dictionary, get the gml id and replace the ordinate values with an xlink.
        xlinkDictionary = {}
        for descriptor in ds.storageDescriptor.descriptors:
            if type(descriptor)==csml.parser.AggregatedArray:
                for comp in descriptor.components:
                    fID=comp.fileList.fileNames.CONTENT
                    if fID in xlinkDictionary:
                        #replace content with xlink
                        gmlid=xlinkDictionary[fID][1]
                        setattr(comp, 'fileListXLINK', csml.parser.csString())
                        comp.fileListXLINK.href='#%s'%gmlid
                        del comp.fileList
                    else:
                        #add to dictionary & set gml:id attribute
                        newid=csml.csmllibs.csmlextra.getRandomID()
                        xlinkDictionary[fID]=(fID, newid)
                        comp.fileList.id=newid
    return ds
   
def resolveXlink(csElement, csDocument):
    '''takes a CSML element, containing Xlinks and resolves them within the csDocument'''
    if hasattr(csElement, 'arcrole'):
       usage=csElement.arcrole.split('#')[0]
       elem=csElement.arcrole.split('#')[1]
       if usage=='http://ndg.nerc.ac.uk/xlinkUsage/insert':
           for child in csElement.CHILDREN:
               print getattr(csElement, child).__class__
               print csElement.CHILDREN
               if getattr(csElement, child).__class__ == elem:
                   print 'yes'
    
    return csDocument