Class wais.WAISInvertedIndex 
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Class wais.WAISInvertedIndex 

java.lang.Object
   |
   +----wais.WAISInvertedIndex
public class WAISInvertedIndex
extends Object
Class to map to a WAISInvertedIndex file. The sole constructor allows us to open up an inverted index file given a database name (source) and a field. From this file we can extract data about terms and data about terms with repect to documents.

Constructor Index

o WAISInvertedIndex(String, String, String)
Create (open up) a WAISInverted index that corresponds to the respective source/field

Method Index

o Close()
Close the inverted index file.
o GetWAISTermDocInfo(long, int)
Given an offset into the inverted index and an entry number of a document return data the terms within that document.
o GetWAISTermInfo(String, long)
Get the term info (not document specific) for a given term at a given offset in the inverted index.

Constructors

o WAISInvertedIndex 
  public WAISInvertedIndex(String indexLocation,
                           String dataBase,
                           String field) throws SourceException
Create (open up) a WAISInverted index that corresponds to the respective source/field
Parameters:
indexLocation - Source specific location of index files.
database - ID of the database
field - Field identifier for the database (may be null).

Methods

o Close 
  public void Close()
Close the inverted index file. Garbage collection (a finalize method) could do this but at an unreliable time.
o GetWAISTermInfo 
  public WAISTermInfo GetWAISTermInfo(String term,
                                      long offset) throws SourceException
Get the term info (not document specific) for a given term at a given offset in the inverted index. The pieces of information we can get at this level are: - the total number of occurrences of the term in the source (multiple occurences in documents count) - number of postings (documents) for the term in the inverted index file - this should match the information in the dictionary file.
Parameters:
term - The term to extract information for.
offset - The offset in the inverted index file at which the term resides.
o GetWAISTermDocInfo 
  public WAISTermDocInfo GetWAISTermDocInfo(long offset,
                                            int docEntryNum) throws SourceException
Given an offset into the inverted index and an entry number of a document return data the terms within that document. The info. we can get here is: - a float value which gives the weight of the term with respect to the document. - the number of the occurrences of the term in the document.
Parameters:
offset - The offset into the inverted index file of the term.
docEntryNum - The entry number of the document for which we wish to extract term specific information. 
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