Show / Hide Table of Contents

    Class Sort

    Encapsulates sort criteria for returned hits.

    The fields used to determine sort order must be carefully chosen. Documents must contain a single term in such a field, and the value of the term should indicate the document's relative position in a given sort order. The field must be indexed, but should not be tokenized, and does not need to be stored (unless you happen to want it back with the rest of your document data). In other words:

    document.Add(new Field("byNumber", x.ToString(CultureInfo.InvariantCulture), Field.Store.NO, Field.Index.NOT_ANALYZED));

    Valid Types of Values

    There are four possible kinds of term values which may be put into sorting fields: s, s, s, or s. Unless SortField objects are specified, the type of value in the field is determined by parsing the first term in the field.

    term values should contain only digits and an optional preceding negative sign. Values must be base 10 and in the range and inclusive. Documents which should appear first in the sort should have low value integers, later documents high values (i.e. the documents should be numbered 1..n where 1 is the first and n the last).

    term values should contain only digits and an optional preceding negative sign. Values must be base 10 and in the range and inclusive. Documents which should appear first in the sort should have low value integers, later documents high values.

    term values should conform to values accepted by (except that NaN and Infinity are not supported). Documents which should appear first in the sort should have low values, later documents high values.

    term values can contain any valid , but should not be tokenized. The values are sorted according to their comparable natural order (). Note that using this type of term value has higher memory requirements than the other two types.

    Object Reuse

    One of these objects can be used multiple times and the sort order changed between usages.

    This class is thread safe.

    Memory Usage

    Sorting uses of caches of term values maintained by the internal HitQueue(s). The cache is static and contains an or array of length IndexReader.MaxDoc for each field name for which a sort is performed. In other words, the size of the cache in bytes is:

    4 * IndexReader.MaxDoc * (# of different fields actually used to sort)

    For fields, the cache is larger: in addition to the above array, the value of every term in the field is kept in memory. If there are many unique terms in the field, this could be quite large.

    Note that the size of the cache is not affected by how many fields are in the index and might be used to sort - only by the ones actually used to sort a result set.

    Created: Feb 12, 2004 10:53:57 AM

    @since lucene 1.4

    Inheritance
    System.Object
    Sort
    Namespace: Lucene.Net.Search
    Assembly: Lucene.Net.dll
    Syntax
    public class Sort : object

    Constructors

    | Improve this Doc View Source

    Sort()

    Sorts by computed relevance. This is the same sort criteria as calling Search(Query, Int32) without a sort criteria, only with slightly more overhead.

    Declaration
    public Sort()
    | Improve this Doc View Source

    Sort(SortField)

    Sorts by the criteria in the given SortField.

    Declaration
    public Sort(SortField field)
    Parameters
    Type Name Description
    SortField field
    | Improve this Doc View Source

    Sort(SortField[])

    Sorts in succession by the criteria in each SortField.

    Declaration
    public Sort(params SortField[] fields)
    Parameters
    Type Name Description
    SortField[] fields

    Fields

    | Improve this Doc View Source

    INDEXORDER

    Represents sorting by index order.

    Declaration
    public static readonly Sort INDEXORDER
    Field Value
    Type Description
    Sort
    | Improve this Doc View Source

    RELEVANCE

    Represents sorting by computed relevance. Using this sort criteria returns the same results as calling Search(Query, Int32)without a sort criteria, only with slightly more overhead.

    Declaration
    public static readonly Sort RELEVANCE
    Field Value
    Type Description
    Sort

    Properties

    | Improve this Doc View Source

    NeedsScores

    Returns true if the relevance score is needed to sort documents.

    Declaration
    public virtual bool NeedsScores { get; }
    Property Value
    Type Description
    System.Boolean

    Methods

    | Improve this Doc View Source

    Equals(Object)

    Returns true if o is equal to this.

    Declaration
    public override bool Equals(object o)
    Parameters
    Type Name Description
    System.Object o
    Returns
    Type Description
    System.Boolean
    | Improve this Doc View Source

    GetHashCode()

    Returns a hash code value for this object.

    Declaration
    public override int GetHashCode()
    Returns
    Type Description
    System.Int32
    | Improve this Doc View Source

    GetSort()

    Representation of the sort criteria.

    Declaration
    public virtual SortField[] GetSort()
    Returns
    Type Description
    SortField[]

    Array of SortField objects used in this sort criteria

    | Improve this Doc View Source

    Rewrite(IndexSearcher)

    Rewrites the SortFields in this Sort, returning a new Sort if any of the fields changes during their rewriting.

    This is a Lucene.NET EXPERIMENTAL API, use at your own risk
    Declaration
    public virtual Sort Rewrite(IndexSearcher searcher)
    Parameters
    Type Name Description
    IndexSearcher searcher

    IndexSearcher to use in the rewriting

    Returns
    Type Description
    Sort

    this if the Sort/Fields have not changed, or a new Sort if there is a change

    | Improve this Doc View Source

    SetSort(SortField)

    Sets the sort to the given criteria.

    Declaration
    public virtual void SetSort(SortField field)
    Parameters
    Type Name Description
    SortField field
    | Improve this Doc View Source

    SetSort(SortField[])

    Sets the sort to the given criteria in succession.

    Declaration
    public virtual void SetSort(params SortField[] fields)
    Parameters
    Type Name Description
    SortField[] fields
    | Improve this Doc View Source

    ToString()

    Declaration
    public override string ToString()
    Returns
    Type Description
    System.String
    • Improve this Doc
    • View Source
    Back to top Copyright © 2020 Licensed to the Apache Software Foundation (ASF)