Examples of it.unimi.dsi.mg4j.search.DocumentIterator

it.unimi.dsi.mg4j.search.DocumentIterator
An iterator over documents (pointers) and their intervals.
Each call to {@link #nextDocument()}will return a document pointer, or -1 if no more documents are available. Just after the call to {@link #nextDocument()}, {@link #intervalIterator(Index)} will return an interval iteratorenumerating intervals in the last returned document for the specified index. The latter method may return, as a special result, a special {@link it.unimi.dsi.mg4j.search.IntervalIterators#TRUE TRUE} value: this means that albeit the current document satisfies the query, there is only a generic empty witness to prove it (see {@link it.unimi.dsi.mg4j.search.IntervalIterators#TRUE TRUE} for some elaboration).
Note that this class implements {@link IntIterator}. Nonetheless, for performance reasons, the preferred access to the document pointers is {@link #nextDocument()}.
The {@link #iterator()} method must be an alias for {@link #intervalIterator()}, and shares the same limitations.
A document iterator is usually structured as composite, with operators as internal nodes and {@link it.unimi.dsi.mg4j.index.IndexIterator}s as leaves. The methods {@link #accept(DocumentIteratorVisitor)} and {@link #acceptOnTruePaths(DocumentIteratorVisitor)} implement the visitor pattern.
The {@link #dispose()} method is intended to recursively release all resources associatedto a composite document iterator. Note that this is not always what you want, as you might be, say, pooling {@linkplain it.unimi.dsi.mg4j.index.IndexReader index readers} to reduce the numberof file open/close operations. For this reason, we intentionally avoid calling the method “close”.
Warning: the interval enumeration can be carried out only just after a call to {@link #nextDocument()}. Subsequent calls to {@link #nextDocument()} or even to {@link java.util.Iterator#hasNext()} will reset the internal state of the iterator. In particular, trying to enumerate intervals after a call to {@link java.util.Iterator#hasNext()} will usually throw an {@link java.lang.IllegalStateException}.

    DocumentIterator differenceIterator = DifferenceDocumentIterator.getInstance( minuendIterator, subtrahendIterator );
    assertEquals( minuendIterator, differenceIterator );
  }


  public void testSpuriousReset() throws IOException {
    DocumentIterator minuendIterator = AndDocumentIterator.getInstance( 
        new IntArrayDocumentIterator( new int[] { 0 }, 
            new int[][][] { 
            { { 0 } }, 
        } ),
        new IntArrayDocumentIterator( new int[] { 0 }, 
            new int[][][] { 
            { { 1 } }, 
        } )
    );


    DocumentIterator subtrahendIterator = new IntArrayDocumentIterator( new int[] { 1 }, new int[][][] { {} } );
    DocumentIterator differenceIterator = DifferenceDocumentIterator.getInstance( minuendIterator, subtrahendIterator );
    assertTrue( differenceIterator.hasNext() );
    assertEquals( 0, differenceIterator.nextDocument() );
    assertEquals( Interval.valueOf( 0, 1 ), differenceIterator.intervalIterator().nextInterval() );
  }

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    assertEquals( 0, differenceIterator.nextDocument() );
    assertEquals( Interval.valueOf( 0, 1 ), differenceIterator.intervalIterator().nextInterval() );
  }


  public void testEnlargment() throws IOException {
    DocumentIterator minuendIterator = new IntArrayDocumentIterator( new int[] { 0, 1, 2, 3 }, 
        new int[][][] { 
        { { 0, 1 }, { 1, 2 } }, 
        { { 0, 1 }, { 1, 2 } },
        { {} }, 
        { { 0, 1 }, { 1, 2 }, { 3, 5 }, { 4, 6 } },
        } );
    DocumentIterator subtrahendIterator = new IntArrayDocumentIterator( new int[] { 0, 1, 2, 3 }, 
        new int[][][] { 
        { {} }, 
        {},
        { { 0, 1 }, { 1, 2 } }, 
        { { 0 }, { 1 }, { 4 } },
        } );
    DocumentIterator differenceIterator = DifferenceDocumentIterator.getInstance( minuendIterator, subtrahendIterator, 1, 1 );
    assertTrue( differenceIterator.hasNext() );
    assertEquals( 1, differenceIterator.nextDocument() );
    assertEquals( Interval.valueOf( 0, 1 ), differenceIterator.intervalIterator().nextInterval() );
    assertEquals( Interval.valueOf( 1, 2 ), differenceIterator.intervalIterator().nextInterval() );
    assertFalse( differenceIterator.intervalIterator().hasNext() );
    assertEquals( 2, differenceIterator.nextDocument() );
    assertEquals( IntervalIterators.TRUE, differenceIterator.intervalIterator() );
    assertEquals( 3, differenceIterator.nextDocument() );
    assertEquals( Interval.valueOf( 0, 1 ), differenceIterator.intervalIterator().nextInterval() );
    assertEquals( Interval.valueOf( 1, 2 ), differenceIterator.intervalIterator().nextInterval() );
    assertEquals( Interval.valueOf( 4, 6 ), differenceIterator.intervalIterator().nextInterval() );
    assertFalse( differenceIterator.intervalIterator().hasNext() );
    assertFalse( differenceIterator.hasNext() );
  }

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it.unimi.dsi.mg4j.index.MultiTermIndexIteratorTest

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it.unimi.dsi.mg4j.search.ConsecutiveDocumentIteratorTest

it.unimi.dsi.mg4j.search.DifferenceDocumentIteratorTest

it.unimi.dsi.mg4j.search.NotDocumentIteratorTest

it.unimi.dsi.mg4j.search.OrderedAndDocumentIteratorTest

it.unimi.dsi.mg4j.search.OrDocumentIteratorTest

it.unimi.dsi.mg4j.search.score.ScorerTest

it.unimi.dsi.mg4j.search.WeightTest

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