org.apache.lucene.index

Class TermEnum

java.lang.Object

org.apache.lucene.index.TermEnum

Direct Known Subclasses:

FilteredTermEnum, FilterIndexReader.FilterTermEnum, InstantiatedTermEnum

public abstract class TermEnum
extends Object

Abstract class for enumerating terms.

Term enumerations are always ordered by Term.compareTo(). Each term in the enumeration is greater than all that precede it.

Constructor Summary

Constructors

Constructor and Description
TermEnum()

Method Summary

Methods

Modifier and Type	Method and Description
abstract void	close() Closes the enumeration to further activity, freeing resources.
abstract int	docFreq() Returns the docFreq of the current Term in the enumeration.
abstract boolean	next() Increments the enumeration to the next element.
boolean	skipTo(Term target) Deprecated. This method is not performant and will be removed in Lucene 3.0. Use IndexReader.terms(Term) to create a new TermEnum positioned at a given term.
abstract Term	term() Returns the current Term in the enumeration.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TermEnum

public TermEnum()

Method Detail

next

public abstract boolean next()
                      throws IOException

Increments the enumeration to the next element. True if one exists.

Throws:

IOException

term

public abstract Term term()

Returns the current Term in the enumeration.

docFreq

public abstract int docFreq()

Returns the docFreq of the current Term in the enumeration.

close

public abstract void close()
                    throws IOException

Closes the enumeration to further activity, freeing resources.

Throws:

IOException

skipTo

public boolean skipTo(Term target)
               throws IOException

Deprecated. This method is not performant and will be removed in Lucene 3.0. Use IndexReader.terms(Term) to create a new TermEnum positioned at a given term.

Skips terms to the first beyond the current whose value is greater or equal to target.

Returns true iff there is such an entry.

Behaves as if written:

   public boolean skipTo(Term target) {
     do {
       if (!next())
             return false;
     } while (target > term());
     return true;
   }
 

Some implementations *could* be considerably more efficient than a linear scan. Check the implementation to be sure.

Throws:

IOException