Source Code for Module grassyknoll.backend.lucene.conversion

 1  """convert python values to and from L{lucene}""" 
 2   
 3  from lucene import NumberTools 
 4  import time 
 5  import datetime 
 6   
 7  ## Lucene can't store floats natively, so we need to intify. This gives us 6 
 8  ## decimal places of precision 
 9  ## XXX it'd be nice to specify this a per-field basis 
10  _float_scale_factor = float(1e6) 
11   
12  ## Lucene's 
13  ## U{DateTools<http://lucene.apache.org/java/2_2_0/api/org/apache/lucene/document/DateTools.html>} 
14  ## are moronic, so we have our own compatible versions. The automatic timezone 
15  ## conversion is particularly stupid. 
16   
17 -def toLucene(value): 
18      """     
19      @arg value: a value to be intelligently converted 
20      @type value: basic Python type 
21       
22      @returns: a Lucene encoding of value 
23      @rtype: unicode 
24      """ 
25      # we disallow str, since lucene assumes it's utf8 (I think) 
26      if isinstance(value, unicode): 
27          return value 
28       
29      if isinstance(value, (int, long)): 
30          value=long(value) # XXX bug in lucene-JCC 
31          return NumberTools.longToString(value) 
32       
33      if isinstance(value, float): 
34          scaled_float = long(value * _float_scale_factor) 
35          return NumberTools.longToString(scaled_float) 
36   
37      if isinstance(value, datetime.datetime): 
38          return unicode(value.strftime('%Y%m%d%H%M%S')) 
39   
40      if isinstance(value, datetime.date): 
41          return unicode(value.strftime('%Y%m%d')) 
42       
43      if isinstance(value, datetime.time): 
44          return unicode(value.strftime('%H%M%S')) 
45       
46      raise TypeError(value) 
47   
48 -def fromLucene(value, typ): 
49      """     
50      @arg value: a Lucene encoding of value 
51      @type value: unicode 
52   
53      @arg typ: the desired Python type 
54      @type typ: type 
55       
56      @returns: an instance of typ 
57      @rtype: typ 
58      """ 
59      if isinstance(value, str): 
60          raise TypeError("Lucene does't support decoding str") 
61       
62      if typ is unicode: 
63          return value 
64       
65      if typ is str: 
66          raise TypeError("Lucene doesn't support converting to str") 
67       
68      if typ is int or typ is long: 
69          return NumberTools.stringToLong(value) 
70       
71      if typ is float: 
72          return float(NumberTools.stringToLong(value))/_float_scale_factor 
73       
74      if typ is datetime.datetime: 
75          return datetime.datetime.strptime(value, '%Y%m%d%H%M%S') 
76       
77      if typ is datetime.date: 
78          return datetime.datetime.strptime(value, '%Y%m%d').date() 
79   
80      if typ is datetime.time: 
81          return datetime.datetime.strptime(value, '%H%M%S').time() 
82       
83      raise TypeError, typ 
84