org.apache.lucene.search
Class DocIdSetIterator

java.lang.Object
  extended by org.apache.lucene.search.DocIdSetIterator
Direct Known Subclasses:
FieldCacheTermsFilter.FieldCacheTermsFilterDocIdSet.FieldCacheTermsFilterDocIdSetIterator, FilteredDocIdSetIterator, OpenBitSetIterator, Scorer

public abstract class DocIdSetIterator
extends Object

This abstract class defines methods to iterate over a set of non-decreasing doc ids. Note that this class assumes it iterates on doc Ids, and therefore NO_MORE_DOCS is set to 2147483647 in order to be used as a sentinel object. Implementations of this class are expected to consider Integer.MAX_VALUE as an invalid value.


Field Summary
static int NO_MORE_DOCS
          When returned by nextDoc(), advance(int) and doc() it means there are no more docs in the iterator.
 
Constructor Summary
DocIdSetIterator()
           
 
Method Summary
 int advance(int target)
          Advances to the first beyond the current whose document number is greater than or equal to target.
 int doc()
          Deprecated. use docID() instead.
 int docID()
          Returns the following: -1 or NO_MORE_DOCS if nextDoc() or advance(int) were not called yet.
 boolean next()
          Deprecated. use nextDoc() instead. This will be removed in 3.0
 int nextDoc()
          Advances to the next document in the set and returns the doc it is currently on, or NO_MORE_DOCS if there are no more docs in the set.
NOTE: in 3.0 this method will become abstract, following the removal of next().
 boolean skipTo(int target)
          Deprecated. use advance(int) instead. This will be removed in 3.0
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

NO_MORE_DOCS

public static final int NO_MORE_DOCS
When returned by nextDoc(), advance(int) and doc() it means there are no more docs in the iterator.

See Also:
Constant Field Values
Constructor Detail

DocIdSetIterator

public DocIdSetIterator()
Method Detail

doc

public int doc()
Deprecated. use docID() instead.

Unsupported anymore. Call docID() instead. This method throws UnsupportedOperationException if called.


docID

public int docID()
Returns the following:

NOTE: in 3.0, this method will become abstract.

Since:
2.9

next

public boolean next()
             throws IOException
Deprecated. use nextDoc() instead. This will be removed in 3.0

Unsupported anymore. Call nextDoc() instead. This method throws UnsupportedOperationException if called.

Throws:
IOException

skipTo

public boolean skipTo(int target)
               throws IOException
Deprecated. use advance(int) instead. This will be removed in 3.0

Unsupported anymore. Call advance(int) instead. This method throws UnsupportedOperationException if called.

Throws:
IOException

nextDoc

public int nextDoc()
            throws IOException
Advances to the next document in the set and returns the doc it is currently on, or NO_MORE_DOCS if there are no more docs in the set.
NOTE: in 3.0 this method will become abstract, following the removal of next(). For backward compatibility it is implemented as:
 public int nextDoc() throws IOException {
   return next() ? doc() : NO_MORE_DOCS;
 }
 
NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.

Throws:
IOException
Since:
2.9

advance

public int advance(int target)
            throws IOException
Advances to the first beyond the current whose document number is greater than or equal to target. Returns the current document number or NO_MORE_DOCS if there are no more docs in the set.

Behaves as if written:

 int advance(int target) {
   int doc;
   while ((doc = nextDoc()) < target) {
   }
   return doc;
 }
 
Some implementations are considerably more efficient than that.

NOTE: certain implementations may return a different value (each time) if called several times in a row with the same target.

NOTE: this method may be called with 2147483647 for efficiency by some Scorers. If your implementation cannot efficiently determine that it should exhaust, it is recommended that you check for that value in each call to this method.

NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.

NOTE: in 3.0 this method will become abstract, following the removal of skipTo(int).

Throws:
IOException
Since:
2.9


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