org.apache.lucene.search
Class FilteredDocIdSetIterator

java.lang.Object
  extended by org.apache.lucene.search.DocIdSetIterator
      extended by org.apache.lucene.search.FilteredDocIdSetIterator

public abstract class FilteredDocIdSetIterator
extends DocIdSetIterator

Abstract decorator class of a DocIdSetIterator implementation that provides on-demand filter/validation mechanism on an underlying DocIdSetIterator. See FilteredDocIdSet.


Field Summary
protected  DocIdSetIterator _innerIter
           
 
Fields inherited from class org.apache.lucene.search.DocIdSetIterator
NO_MORE_DOCS
 
Constructor Summary
FilteredDocIdSetIterator(DocIdSetIterator innerIter)
          Constructor.
 
Method Summary
 int advance(int target)
          Advances to the first beyond the current whose document number is greater than or equal to target.
 int docID()
          Returns the following: -1 or DocIdSetIterator.NO_MORE_DOCS if DocIdSetIterator.nextDoc() or DocIdSetIterator.advance(int) were not called yet.
protected abstract  boolean match(int doc)
          Validation method to determine whether a docid should be in the result set.
 int nextDoc()
          Advances to the next document in the set and returns the doc it is currently on, or DocIdSetIterator.NO_MORE_DOCS if there are no more docs in the set.
NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

_innerIter

protected DocIdSetIterator _innerIter
Constructor Detail

FilteredDocIdSetIterator

public FilteredDocIdSetIterator(DocIdSetIterator innerIter)
Constructor.

Parameters:
innerIter - Underlying DocIdSetIterator.
Method Detail

match

protected abstract boolean match(int doc)
                          throws IOException
Validation method to determine whether a docid should be in the result set.

Parameters:
doc - docid to be tested
Returns:
true if input docid should be in the result set, false otherwise.
Throws:
IOException
See Also:
FilteredDocIdSetIterator(DocIdSetIterator)

docID

public int docID()
Description copied from class: DocIdSetIterator
Returns the following:

Specified by:
docID in class DocIdSetIterator

nextDoc

public int nextDoc()
            throws IOException
Description copied from class: DocIdSetIterator
Advances to the next document in the set and returns the doc it is currently on, or DocIdSetIterator.NO_MORE_DOCS if there are no more docs in the set.
NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.

Specified by:
nextDoc in class DocIdSetIterator
Throws:
IOException

advance

public int advance(int target)
            throws IOException
Description copied from class: DocIdSetIterator
Advances to the first beyond the current whose document number is greater than or equal to target. Returns the current document number or DocIdSetIterator.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: when target ≤ current implementations may opt not to advance beyond their current DocIdSetIterator.docID().

NOTE: this method may be called with DocIdSetIterator.NO_MORE_DOCS 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.

Specified by:
advance in class DocIdSetIterator
Throws:
IOException


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