it.unimi.dsi.mg4j.index
Class AbstractIndexIterator

java.lang.Object
  extended by it.unimi.dsi.fastutil.ints.AbstractIntIterator
      extended by it.unimi.dsi.mg4j.index.AbstractIndexIterator
All Implemented Interfaces:
IntIterator, IndexIterator, DocumentIterator, Iterable<Interval>, Iterator<Integer>
Direct Known Subclasses:
BitStreamHPIndexReader.BitStreamHPIndexReaderIndexIterator, BitStreamIndexReader.BitStreamIndexReaderIndexIterator, GammaDeltaGammaDeltaBitStreamHPIndexReader.BitStreamHPIndexReaderIndexIterator, GammaDeltaGammaDeltaBitStreamIndexReader.BitStreamIndexReaderIndexIterator, SkipGammaDeltaGammaDeltaBitStreamIndexReader.BitStreamIndexReaderIndexIterator

public abstract class AbstractIndexIterator
extends AbstractIntIterator
implements IndexIterator

A very basic abstract implementation of an index interator, providing an obvious implementation of term(), id(), and of the visiting methods.


Field Summary
protected  int id
           
protected  String term
           
 
Constructor Summary
AbstractIndexIterator()
           
 
Method Summary
 boolean accept(DocumentIteratorVisitor visitor)
          Accepts a visitor.
 boolean acceptOnTruePaths(DocumentIteratorVisitor visitor)
          Accepts a visitor after a call to DocumentIterator.nextDocument(), limiting recursion to true paths.
 int id()
          Returns the id of this index iterator.
 void id(int id)
          Sets the id of this index iterator.
 IntervalIterator iterator()
          Deprecated. 
 String term()
          Returns the term whose inverted list is returned by this index iterator.
 void term(CharSequence term)
          Sets the term whose inverted list is returned by this index iterator.
 
Methods inherited from class it.unimi.dsi.fastutil.ints.AbstractIntIterator
next, nextInt, remove, skip
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface it.unimi.dsi.mg4j.index.IndexIterator
count, frequency, index, payload, positionArray, positions, positions, termNumber
 
Methods inherited from interface it.unimi.dsi.mg4j.search.DocumentIterator
dispose, document, indices, intervalIterator, intervalIterator, intervalIterators, nextDocument, nextInt, skipTo
 
Methods inherited from interface it.unimi.dsi.fastutil.ints.IntIterator
skip
 
Methods inherited from interface java.util.Iterator
hasNext, next, remove
 

Field Detail

term

protected String term

id

protected int id
Constructor Detail

AbstractIndexIterator

public AbstractIndexIterator()
Method Detail

term

public void term(CharSequence term)
Description copied from interface: IndexIterator
Sets the term whose inverted list is returned by this index iterator.

Usually, the term is automatically set by Index.documents(CharSequence) or by IndexReader.documents(CharSequence), but you can use this method to ensure that IndexIterator.term() doesn't throw an exception.

Instances of Index.EmptyIndexIterator are allowed to ignore silently calls to this method.

Specified by:
term in interface IndexIterator
Parameters:
term - a character sequence (that will be defensively copied) that will be assumed to be the term whose inverted list is returned by this index iterator.

term

public String term()
Description copied from interface: IndexIterator
Returns the term whose inverted list is returned by this index iterator.

Usually, the term is automatically set by IndexReader.documents(CharSequence) or IndexReader.documents(int), but you can supply your own term with IndexIterator.term(CharSequence).

Instances of Index.EmptyIndexIterator can return null.

Specified by:
term in interface IndexIterator
Returns:
the term over which this iterator is built, as a compact mutable string.
See Also:
IndexIterator.termNumber()

id

public void id(int id)
Description copied from interface: IndexIterator
Sets the id of this index iterator.

The id is an integer associated to each index iterator. It has no specific semantics, and can be used differently in different contexts. A typical usage pattern, for instance, is using it to assign a unique number to the index iterators contained in a composited document iterator (say, numbering consecutively the leaves of the composite).

Instances of Index.EmptyIndexIterator are allowed to ignore silently calls to this method.

Specified by:
id in interface IndexIterator
Parameters:
id - the new id for this index iterator.

id

public int id()
Description copied from interface: IndexIterator
Returns the id of this index iterator.

Instances of Index.EmptyIndexIterator are allowed to return -1.

Specified by:
id in interface IndexIterator
Returns:
the id of this index iterator.
See Also:
IndexIterator.id(int)

accept

public boolean accept(DocumentIteratorVisitor visitor)
               throws IOException
Description copied from interface: DocumentIterator
Accepts a visitor.

A document iterator is usually structured as composite, with operators as internal nodes and IndexIterators as leaves. This method implements the visitor pattern.

Specified by:
accept in interface DocumentIterator
Parameters:
visitor - the visitor.
Returns:
true if the visit should continue.
Throws:
IOException

acceptOnTruePaths

public boolean acceptOnTruePaths(DocumentIteratorVisitor visitor)
                          throws IOException
Description copied from interface: DocumentIterator
Accepts a visitor after a call to DocumentIterator.nextDocument(), limiting recursion to true paths.

After a call to DocumentIterator.nextDocument(), a document iterator is positioned over a document. This call is equivalent to DocumentIterator.accept(DocumentIteratorVisitor), but visits only along true paths.

We define a true path as a path from the root of the composite that passes only through nodes whose associated subtree is positioned on the same document of the root. Note that OrDocumentIterators detach exhausted iterators from the composite tree, so true paths define the subtree that is causing the current document to satisfy the query represented by this document iterator.

For more elaboration, and the main application of this method, see CounterCollectionVisitor.

Specified by:
acceptOnTruePaths in interface DocumentIterator
Parameters:
visitor - the visitor.
Returns:
true if the visit should continue.
Throws:
IOException
See Also:
DocumentIterator.accept(DocumentIteratorVisitor), CounterCollectionVisitor

iterator

@Deprecated
public IntervalIterator iterator()
Deprecated. 

Description copied from interface: DocumentIterator
An alias for DocumentIterator.intervalIterator(), that has the same limitations (i.e., it will work only if there is just one index), and that catches IOExceptions.

Specified by:
iterator in interface DocumentIterator
Specified by:
iterator in interface Iterable<Interval>
Returns:
an interval iterator.