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java.lang.Objectit.unimi.dsi.fastutil.ints.AbstractIntIterator
it.unimi.dsi.mg4j.index.AbstractIndexIterator
it.unimi.dsi.mg4j.index.wired.GammaDeltaGammaDeltaBitStreamIndexReader.BitStreamIndexReaderIndexIterator
protected static final class GammaDeltaGammaDeltaBitStreamIndexReader.BitStreamIndexReaderIndexIterator
Field Summary | |
---|---|
protected int |
count
The current count (if this index contains counts). |
protected CompressionFlags.Coding |
countCoding
The cached copy of index.countCoding . |
protected int |
currentDocument
The last document pointer we read from current list, -1 if we just read the frequency, Integer.MAX_VALUE if we are beyond the end of list. |
protected int |
currentTerm
The current term. |
protected int |
frequency
The current frequency. |
protected boolean |
hasPointers
Whether the current terms has pointers at all (this happens when the frequency is smaller than the number of documents). |
protected InputBitStream |
ibs
The underlying input bit stream. |
protected BitStreamIndex |
index
The reference index. |
protected int |
numberOfDocumentRecord
The number of the document record we are going to read inside the current inverted list. |
protected CompressionFlags.Coding |
pointerCoding
The cached copy of index.pointerCoding . |
protected int[] |
positionCache
The cached position array. |
protected CompressionFlags.Coding |
positionCoding
The cached copy of index.positionCoding . |
protected int |
state
This variable tracks the current state of the reader. |
Fields inherited from class it.unimi.dsi.mg4j.index.AbstractIndexIterator |
---|
id, term |
Constructor Summary | |
---|---|
GammaDeltaGammaDeltaBitStreamIndexReader.BitStreamIndexReaderIndexIterator(GammaDeltaGammaDeltaBitStreamIndexReader parent,
InputBitStream ibs)
|
Method Summary | |
---|---|
protected IndexIterator |
advance()
|
int |
count()
Returns the count, that is, the number of occurrences of the term in the current document. |
void |
dispose()
Disposes this document iterator, releasing all resources. |
int |
document()
Returns the last document returned by DocumentIterator.nextDocument() . |
int |
frequency()
Returns the frequency, that is, the number of documents that will be returned by this iterator. |
boolean |
hasNext()
|
Index |
index()
Returns the index over which this iterator is built. |
ReferenceSet<Index> |
indices()
Returns the set of indices over which this iterator is built. |
IntervalIterator |
intervalIterator()
Returns the interval iterator of this document iterator for single-index queries. |
IntervalIterator |
intervalIterator(Index index)
Returns the interval iterator of this document iterator for the given index. |
Reference2ReferenceMap<Index,IntervalIterator> |
intervalIterators()
Returns an unmodifiable map from indices to interval iterators. |
int |
nextDocument()
Returns the next document provided by this document iterator, or -1 if no more documents are available. |
int |
nextInt()
Returns the next document. |
Payload |
payload()
Returns the payload, if any, associated with the current document. |
protected void |
position(int term)
Positions the index on the inverted list of a given term. |
int[] |
positionArray()
Returns the positions at which the term appears in the current document in an array. |
IntIterator |
positions()
Returns the positions at which the term appears in the current document. |
int |
positions(int[] position)
Stores the positions at which the term appears in the current document in a given array. |
int |
skipTo(int p)
Skips all documents smaller than n . |
int |
termNumber()
Returns the number of the term whose inverted list is returned by this index iterator. |
String |
toString()
|
protected void |
updatePositionCache()
We read positions, assuming state <= BEFORE_POSITIONS |
Methods inherited from class it.unimi.dsi.mg4j.index.AbstractIndexIterator |
---|
accept, acceptOnTruePaths, id, id, iterator, term, term |
Methods inherited from class it.unimi.dsi.fastutil.ints.AbstractIntIterator |
---|
next, remove, skip |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Methods inherited from interface it.unimi.dsi.mg4j.index.IndexIterator |
---|
id, id, term, term |
Methods inherited from interface it.unimi.dsi.mg4j.search.DocumentIterator |
---|
accept, acceptOnTruePaths, iterator |
Methods inherited from interface it.unimi.dsi.fastutil.ints.IntIterator |
---|
skip |
Methods inherited from interface java.util.Iterator |
---|
next, remove |
Field Detail |
---|
protected final BitStreamIndex index
protected final InputBitStream ibs
protected final CompressionFlags.Coding pointerCoding
index.pointerCoding
.
protected final CompressionFlags.Coding countCoding
index.countCoding
.
protected final CompressionFlags.Coding positionCoding
index.positionCoding
.
protected int currentTerm
protected int frequency
protected boolean hasPointers
frequency
is smaller than the number of documents).
protected int count
protected int currentDocument
Integer.MAX_VALUE
if we are beyond the end of list.
protected int numberOfDocumentRecord
protected int state
protected int[] positionCache
Constructor Detail |
---|
public GammaDeltaGammaDeltaBitStreamIndexReader.BitStreamIndexReaderIndexIterator(GammaDeltaGammaDeltaBitStreamIndexReader parent, InputBitStream ibs)
Method Detail |
---|
protected void position(int term) throws IOException
This method can be called at any time. Note that it is always possible to call this method with argument 0, even if offsets have not been loaded.
term
- a term.
IOException
public int termNumber()
IndexIterator
Usually, the term number is automatically set by IndexReader.documents(CharSequence)
or IndexReader.documents(int)
.
Instances of Index.EmptyIndexIterator
can return -1
.
termNumber
in interface IndexIterator
Index.EmptyIndexIterator
.IndexIterator.term()
protected IndexIterator advance() throws IOException
IOException
public Index index()
IndexIterator
index
in interface IndexIterator
public int frequency()
IndexIterator
frequency
in interface IndexIterator
public int document()
DocumentIterator
DocumentIterator.nextDocument()
.
document
in interface DocumentIterator
DocumentIterator.nextDocument()
, or -1 if no document has been returned yet.public Payload payload() throws IOException
IndexIterator
payload
in interface IndexIterator
IOException
public int count() throws IOException
IndexIterator
count
in interface IndexIterator
IOException
protected void updatePositionCache() throws IOException
IOException
public IntIterator positions() throws IOException
IndexIterator
positions
in interface IndexIterator
IOException
public int[] positionArray() throws IOException
IndexIterator
Implementations are allowed to return the same array across different calls to this method.
positionArray
in interface IndexIterator
IOException
public int positions(int[] position) throws IOException
IndexIterator
If the array is not large enough (i.e., it does not contain IndexIterator.count()
elements),
this method will return a negative number (the opposite of the count).
positions
in interface IndexIterator
position
- an array that will be used to store positions.
positions
cannot
hold all positions.
IOException
public int nextDocument() throws IOException
DocumentIterator
Warning: the specification of this method has significantly changed as of MG4J 1.2.
The special return value -1 is used to mark the end of iteration (a NoSuchElementException
would have been thrown before in that case, so ho harm should be caused by this change). The reason
for this change is providing fully lazy iteration over documents. Fully lazy iteration
does not provide an hasNext()
method—you have to actually ask for the next
element and check the return value. Fully lazy iteration is much lighter on method calls (half) and
in most (if not all) MG4J classes leads to a much simpler logic. Moreover, DocumentIterator.nextDocument()
can be specified as throwing an IOException
, which avoids the pernicious proliferation
of try/catch blocks in very short, low-level methods (it was having a detectable impact on performance).
nextDocument
in interface DocumentIterator
IOException
public int skipTo(int p) throws IOException
DocumentIterator
n
.
Define the current document k
associated with this document iterator
as follows:
DocumentIterator.nextDocument()
and this method have never been called;
Integer.MAX_VALUE
, if a call to this method returned Integer.MAX_VALUE
;
DocumentIterator.nextDocument()
or this method, otherwise.
If k
is larger than or equal to n
, then
this method does nothing and returns k
. Otherwise, a
call to this method is equivalent to
while( ( k = nextDocument() ) < n && k != -1 ); return k == -1 ? Integer.MAX_VALUE : k;
Thus, when a result k
≠ Integer.MAX_VALUE
is returned, the state of this iterator
will be exactly the same as after a call to DocumentIterator.nextDocument()
that returned k
.
In particular, the first document larger than or equal to n
(when returned
by this method) will not be returned by the next call to
DocumentIterator.nextDocument()
.
skipTo
in interface DocumentIterator
p
- a document pointer.
n
if available, Integer.MAX_VALUE
otherwise.
IOException
public void dispose() throws IOException
DocumentIterator
This method should propagate down to the underlying index iterators, where it should release resources such as open files and network connections. If you're doing your own resource tracking and pooling, then you do not need to call this method.
dispose
in interface DocumentIterator
IOException
public boolean hasNext()
hasNext
in interface Iterator<Integer>
public int nextInt()
DocumentIterator
nextInt
in interface IntIterator
nextInt
in interface DocumentIterator
nextInt
in class AbstractIntIterator
DocumentIterator.nextDocument()
public String toString()
toString
in class Object
public Reference2ReferenceMap<Index,IntervalIterator> intervalIterators() throws IOException
DocumentIterator
After a call to DocumentIterator.nextDocument()
, this map
can be used to retrieve the intervals in the current document. An invocation of Map.get(java.lang.Object)
on this map with argument index
yields the same result as
intervalIterator(index)
.
intervalIterators
in interface DocumentIterator
IOException
DocumentIterator.intervalIterator(Index)
public IntervalIterator intervalIterator() throws IOException
DocumentIterator
This is a commodity method that can be used only for queries built over a single index.
intervalIterator
in interface DocumentIterator
IOException
DocumentIterator.intervalIterator(Index)
public IntervalIterator intervalIterator(Index index) throws IOException
DocumentIterator
After a call to DocumentIterator.nextDocument()
, this iterator
can be used to retrieve the intervals in the current document (the
one returned by DocumentIterator.nextDocument()
) for
the index index
.
Note that if all indices have positions, it is guaranteed that at least one index will return an interval. However, for disjunctive queries it cannot be guaranteed that all indices will return an interval.
Indices without positions always return IntervalIterators.TRUE
.
Thus, in presence of indices without positions it is possible that no
intervals at all are available.
intervalIterator
in interface DocumentIterator
index
- an index (must be one over which the query was built).
index
.
IOException
public ReferenceSet<Index> indices()
DocumentIterator
indices
in interface DocumentIterator
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