public abstract class FilteredTermsEnum extends TermsEnum
Term enumerations are always ordered by
getComparator()
. Each term in the enumeration is
greater than all that precede it.
Please note: Consumers of this enum cannot
call seek()
, it is forward only; it throws
UnsupportedOperationException
when a seeking method
is called.
Modifier and Type | Class and Description |
---|---|
protected static class |
FilteredTermsEnum.AcceptStatus
Return value, if term should be accepted or the iteration should
END . |
TermsEnum.SeekStatus
Modifier and Type | Field and Description |
---|---|
protected BytesRef |
actualTerm
Which term the enum is currently positioned to.
|
protected TermsEnum |
tenum
The delegate
TermsEnum . |
Constructor and Description |
---|
FilteredTermsEnum(TermsEnum tenum)
Creates a filtered
TermsEnum on a terms enum. |
FilteredTermsEnum(TermsEnum tenum,
boolean startWithSeek)
Creates a filtered
TermsEnum on a terms enum. |
Modifier and Type | Method and Description |
---|---|
protected abstract FilteredTermsEnum.AcceptStatus |
accept(BytesRef term)
Return if term is accepted, not accepted or the iteration should ended
(and possibly seek).
|
AttributeSource |
attributes()
Returns the related attributes, the returned
AttributeSource
is shared with the delegate TermsEnum . |
int |
docFreq()
Returns the number of documents containing the current
term.
|
DocsEnum |
docs(Bits bits,
DocsEnum reuse,
int flags)
Get
DocsEnum for the current term, with
control over whether freqs are required. |
DocsAndPositionsEnum |
docsAndPositions(Bits bits,
DocsAndPositionsEnum reuse,
int flags)
Get
DocsAndPositionsEnum for the current term,
with control over whether offsets and payloads are
required. |
Comparator<BytesRef> |
getComparator()
Return the
BytesRef Comparator used to sort terms provided by the
iterator. |
BytesRef |
next()
Increments the iteration to the next
BytesRef in the iterator. |
protected BytesRef |
nextSeekTerm(BytesRef currentTerm)
On the first call to
next() or if accept(org.apache.lucene.util.BytesRef) returns
FilteredTermsEnum.AcceptStatus.YES_AND_SEEK or FilteredTermsEnum.AcceptStatus.NO_AND_SEEK ,
this method will be called to eventually seek the underlying TermsEnum
to a new position. |
long |
ord()
Returns ordinal position for current term.
|
TermsEnum.SeekStatus |
seekCeil(BytesRef term)
This enum does not support seeking!
|
boolean |
seekExact(BytesRef term)
This enum does not support seeking!
|
void |
seekExact(BytesRef term,
TermState state)
This enum does not support seeking!
|
void |
seekExact(long ord)
This enum does not support seeking!
|
protected void |
setInitialSeekTerm(BytesRef term)
Use this method to set the initial
BytesRef
to seek before iterating. |
BytesRef |
term()
Returns current term.
|
TermState |
termState()
Returns the filtered enums term state
|
long |
totalTermFreq()
Returns the total number of occurrences of this term
across all documents (the sum of the freq() for each
doc that has this term).
|
docs, docsAndPositions
protected BytesRef actualTerm
public FilteredTermsEnum(TermsEnum tenum)
TermsEnum
on a terms enum.tenum
- the terms enumeration to filter.protected abstract FilteredTermsEnum.AcceptStatus accept(BytesRef term) throws IOException
IOException
protected final void setInitialSeekTerm(BytesRef term)
BytesRef
to seek before iterating. This is a convenience method for
subclasses that do not override nextSeekTerm(org.apache.lucene.util.BytesRef)
.
If the initial seek term is null
(default),
the enum is empty.
You can only use this method, if you keep the default
implementation of nextSeekTerm(org.apache.lucene.util.BytesRef)
.
protected BytesRef nextSeekTerm(BytesRef currentTerm) throws IOException
next()
or if accept(org.apache.lucene.util.BytesRef)
returns
FilteredTermsEnum.AcceptStatus.YES_AND_SEEK
or FilteredTermsEnum.AcceptStatus.NO_AND_SEEK
,
this method will be called to eventually seek the underlying TermsEnum
to a new position.
On the first call, currentTerm
will be null
, later
calls will provide the term the underlying enum is positioned at.
This method returns per default only one time the initial seek term
and then null
, so no repositioning is ever done.
Override this method, if you want a more sophisticated TermsEnum,
that repositions the iterator during enumeration.
If this method always returns null
the enum is empty.
Please note: This method should always provide a greater term than the last enumerated term, else the behaviour of this enum violates the contract for TermsEnums.
IOException
public AttributeSource attributes()
AttributeSource
is shared with the delegate TermsEnum
.attributes
in class TermsEnum
public BytesRef term() throws IOException
TermsEnum
term
in class TermsEnum
IOException
public Comparator<BytesRef> getComparator()
BytesRefIterator
BytesRef
Comparator used to sort terms provided by the
iterator. This may return null if there are no items or the iterator is not
sorted. Callers may invoke this method many times, so it's best to cache a
single instance & reuse it.public int docFreq() throws IOException
TermsEnum
TermsEnum.SeekStatus.END
.docFreq
in class TermsEnum
IOException
public long totalTermFreq() throws IOException
TermsEnum
totalTermFreq
in class TermsEnum
IOException
public boolean seekExact(BytesRef term) throws IOException
seekExact
in class TermsEnum
UnsupportedOperationException
- In general, subclasses do not
support seeking.IOException
public TermsEnum.SeekStatus seekCeil(BytesRef term) throws IOException
seekCeil
in class TermsEnum
UnsupportedOperationException
- In general, subclasses do not
support seeking.IOException
public void seekExact(long ord) throws IOException
seekExact
in class TermsEnum
UnsupportedOperationException
- In general, subclasses do not
support seeking.IOException
public long ord() throws IOException
TermsEnum
UnsupportedOperationException
). Do not call this
when the enum is unpositioned.ord
in class TermsEnum
IOException
public DocsEnum docs(Bits bits, DocsEnum reuse, int flags) throws IOException
TermsEnum
DocsEnum
for the current term, with
control over whether freqs are required. Do not
call this when the enum is unpositioned. This method
will not return null.docs
in class TermsEnum
bits
- unset bits are documents that should not
be returnedreuse
- pass a prior DocsEnum for possible reuseflags
- specifies which optional per-document values
you require; see DocsEnum.FLAG_FREQS
IOException
TermsEnum.docs(Bits, DocsEnum, int)
public DocsAndPositionsEnum docsAndPositions(Bits bits, DocsAndPositionsEnum reuse, int flags) throws IOException
TermsEnum
DocsAndPositionsEnum
for the current term,
with control over whether offsets and payloads are
required. Some codecs may be able to optimize their
implementation when offsets and/or payloads are not required.
Do not call this when the enum is unpositioned. This
will return null if positions were not indexed.docsAndPositions
in class TermsEnum
bits
- unset bits are documents that should not
be returnedreuse
- pass a prior DocsAndPositionsEnum for possible reuseflags
- specifies which optional per-position values you
require; see DocsAndPositionsEnum.FLAG_OFFSETS
and
DocsAndPositionsEnum.FLAG_PAYLOADS
.IOException
public void seekExact(BytesRef term, TermState state) throws IOException
seekExact
in class TermsEnum
term
- the term the TermState corresponds tostate
- the TermState
UnsupportedOperationException
- In general, subclasses do not
support seeking.IOException
public TermState termState() throws IOException
termState
in class TermsEnum
IOException
TermState
,
TermsEnum.seekExact(BytesRef, TermState)
public BytesRef next() throws IOException
BytesRefIterator
BytesRef
in the iterator.
Returns the resulting BytesRef
or null
if the end of
the iterator is reached. The returned BytesRef may be re-used across calls
to next. After this method returns null, do not call it again: the results
are undefined.BytesRef
in the iterator or null
if
the end of the iterator is reached.IOException
- If there is a low-level I/O error.Copyright © 2000-2014 Apache Software Foundation. All Rights Reserved.