java.lang.Object | ||
↳ | org.apache.lucene.index.IndexReader | |
↳ | org.apache.lucene.index.ParallelReader |
An IndexReader which reads multiple, parallel indexes. Each index added must have the same number of documents, but typically each contains different fields. Each document contains the union of the fields of all documents with the same document number. When searching, matches for a query term are from the first index added that has the field.
This is useful, e.g., with collections that have large fields which change rarely and small fields that change more frequently. The smaller fields may be re-indexed in a new index and both indexes may be searched together.
Warning: It is up to you to make sure all indexes are created and modified the same way. For example, if you add documents to one index, you need to add the same documents in the same order to the other indexes. Failure to do so will result in undefined behavior.
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Inherited Fields | |||||||||||
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From class
org.apache.lucene.index.IndexReader
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Public Constructors | |||||||||||
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Construct a ParallelReader.
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Construct a ParallelReader.
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Public Methods | |||||||||||
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Add an IndexReader.
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Add an IndexReader whose stored fields will not be returned.
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Efficiently clones the IndexReader (sharing most
internal state).
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Returns the number of documents containing the term
t . | |||||||||||
Get the
Document at the n
th position. | |||||||||||
Get a list of unique field names that exist in this index and have the specified
field option information.
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Load the Term Vector into a user-defined data structure instead of relying on the parallel arrays of
the
TermFreqVector . | |||||||||||
Return a term frequency vector for the specified document and field.
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Map all the term vectors for all fields in a Document
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Return an array of term frequency vectors for the specified document.
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Not implemented.
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Returns true if any documents have been deleted
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Returns true if there are norms stored for this field.
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Checks recursively if all subreaders are up to date.
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Returns true if document n has been deleted
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Checks recursively if all subindexes are optimized
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Returns one greater than the largest possible document number.
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Returns the byte-encoded normalization factor for the named field of
every document.
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Reads the byte-encoded normalization factor for the named field of every
document.
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Returns the number of documents in this index.
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Tries to reopen the subreaders.
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Returns an unpositioned
TermDocs enumerator. | |||||||||||
Returns an enumeration of all the documents which contain
term . | |||||||||||
Returns an enumeration of all the documents which contain
term . | |||||||||||
Returns an unpositioned
TermPositions enumerator. | |||||||||||
Returns an enumeration of all terms starting at a given term.
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Returns an enumeration of all the terms in the index.
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Protected Methods | |||||||||||
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Implements close.
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Implements commit.
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Implements deletion of the document numbered
docNum . | |||||||||||
Implements setNorm in subclass.
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Implements actual undeleteAll() in subclass.
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Inherited Methods | |||||||||||
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From class
org.apache.lucene.index.IndexReader
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From class
java.lang.Object
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From interface
java.io.Closeable
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Construct a ParallelReader.
Note that all subreaders are closed if this ParallelReader is closed.
IOException |
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Construct a ParallelReader.
closeSubReaders | indicates whether the subreaders should be closed when this ParallelReader is closed |
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IOException |
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Add an IndexReader.
IOException | if there is a low-level IO error |
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Add an IndexReader whose stored fields will not be returned. This can accelerate search when stored fields are only needed from a subset of the IndexReaders.
IllegalArgumentException | if not all indexes contain the same number of documents |
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IllegalArgumentException | if not all indexes have the same value
of maxDoc() |
IOException | if there is a low-level IO error |
Efficiently clones the IndexReader (sharing most internal state).
On cloning a reader with pending changes (deletions, norms), the original reader transfers its write lock to the cloned reader. This means only the cloned reader may make further changes to the index, and commit the changes to the index on close, but the old reader still reflects all changes made up until it was cloned.
Like reopen()
, it's safe to make changes to
either the original or the cloned reader: all shared
mutable state obeys "copy on write" semantics to ensure
the changes are not seen by other readers.
Returns the number of documents containing the term t
.
IOException |
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Get the Document
at the n
th position. The FieldSelector
may be used to determine
what Field
s to load and how they should
be loaded. NOTE: If this Reader (more specifically, the underlying
FieldsReader
) is closed before the lazy
Field
is loaded an exception may be
thrown. If you want the value of a lazy
Field
to be available after closing you
must explicitly load it or fetch the Document again with a new loader.
NOTE: for performance reasons, this method does not check if the
requested document is deleted, and therefore asking for a deleted document
may yield unspecified results. Usually this is not required, however you
can call isDeleted(int)
with the requested document ID to verify
the document is not deleted.
n | Get the document at the n th position |
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fieldSelector | The FieldSelector to use to determine what
Fields should be loaded on the Document. May be null, in which case
all Fields will be loaded. |
Document
at the nth positionCorruptIndexException | |
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IOException |
Get a list of unique field names that exist in this index and have the specified field option information.
fieldNames | specifies which field option should be available for the returned fields |
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Load the Term Vector into a user-defined data structure instead of relying on the parallel arrays of
the TermFreqVector
.
docNumber | The number of the document to load the vector for |
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field | The name of the field to load |
mapper | The TermVectorMapper to process the vector. Must not be null |
IOException |
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Return a term frequency vector for the specified document and field. The
returned vector contains terms and frequencies for the terms in
the specified field of this document, if the field had the storeTermVector
flag set. If termvectors had been stored with positions or offsets, a
TermPositionVector
is returned.
n | document for which the term frequency vector is returned |
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field | field for which the term frequency vector is returned. |
IOException |
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Map all the term vectors for all fields in a Document
docNumber | The number of the document to load the vector for |
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mapper | The TermVectorMapper to process the vector. Must not be null |
IOException |
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Return an array of term frequency vectors for the specified document.
The array contains a vector for each vectorized field in the document.
Each vector contains terms and frequencies for all terms in a given vectorized field.
If no such fields existed, the method returns null. The term vectors that are
returned may either be of type TermFreqVector
or of type TermPositionVector
if
positions or offsets have been stored.
n | document for which term frequency vectors are returned |
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IOException |
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Returns true if any documents have been deleted
Returns true if there are norms stored for this field.
IOException |
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Checks recursively if all subreaders are up to date.
CorruptIndexException | |
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IOException |
Returns true if document n has been deleted
Checks recursively if all subindexes are optimized
true
if the index is optimized; false
otherwiseReturns one greater than the largest possible document number. This may be used to, e.g., determine how big to allocate an array which will have an element for every document number in an index.
Returns the byte-encoded normalization factor for the named field of every document. This is used by the search code to score documents.
IOException |
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Reads the byte-encoded normalization factor for the named field of every document. This is used by the search code to score documents.
IOException |
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Returns the number of documents in this index.
Tries to reopen the subreaders.
If one or more subreaders could be re-opened (i. e. subReader.reopen()
returned a new instance != subReader), then a new ParallelReader instance
is returned, otherwise this instance is returned.
A re-opened instance might share one or more subreaders with the old
instance. Index modification operations result in undefined behavior
when performed before the old instance is closed.
(see reopen()
).
If subreaders are shared, then the reference count of those readers is increased to ensure that the subreaders remain open until the last referring reader is closed.
CorruptIndexException | if the index is corrupt |
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IOException | if there is a low-level IO error |
Returns an enumeration of all the documents which contain
term
. For each document, the document number, the frequency of
the term in that document is also provided, for use in
search scoring. If term is null, then all non-deleted
docs are returned with freq=1.
Thus, this method implements the mapping:
The enumeration is ordered by document number. Each document number is greater than all that precede it in the enumeration.
IOException |
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Returns an enumeration of all the documents which contain
term
. For each document, in addition to the document number
and frequency of the term in that document, a list of all of the ordinal
positions of the term in the document is available. Thus, this method
implements the mapping:
This positional information facilitates phrase and proximity searching.
The enumeration is ordered by document number. Each document number is greater than all that precede it in the enumeration.
IOException |
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Returns an unpositioned TermPositions
enumerator.
IOException |
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Returns an enumeration of all terms starting at a given term. If the given term does not exist, the enumeration is positioned at the first term greater than the supplied term. The enumeration is ordered by Term.compareTo(). Each term is greater than all that precede it in the enumeration.
IOException |
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Returns an enumeration of all the terms in the index. The
enumeration is ordered by Term.compareTo(). Each term is greater
than all that precede it in the enumeration. Note that after
calling terms(), next()
must be called
on the resulting enumeration before calling other methods such as
term()
.
IOException |
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Implements deletion of the document numbered docNum
.
Applications should call deleteDocument(int)
or deleteDocuments(Term)
.
CorruptIndexException | |
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IOException |
Implements setNorm in subclass.
CorruptIndexException | |
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IOException |
Implements actual undeleteAll() in subclass.
CorruptIndexException | |
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IOException |