/*
* Copyright 2004 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
using System;
namespace Lucene.Net.Search{
/// <summary> Stores information about how to sort documents by terms in an individual
/// field. Fields must be indexed in order to sort by them.
///
/// <p>Created: Feb 11, 2004 1:25:29 PM
///
/// </summary>
/// <author> Tim Jones (Nacimiento Software)
/// </author>
/// <since> lucene 1.4
/// </since>
/// <version> $Id: SortField.java 150357 2004-05-24 22:51:42Z tjones $
/// </version>
/// <seealso cref="Sort">
/// </seealso>
[Serializable]
public class SortField
{
/// <summary>Sort by document score (relevancy). Sort values are Float and higher
/// values are at the front.
/// </summary>
public const int SCORE = 0;
/// <summary>Sort by document number (index order). Sort values are Integer and lower
/// values are at the front.
/// </summary>
public const int DOC = 1;
/// <summary>Guess type of sort based on field contents. A regular expression is used
/// to look at the first term indexed for the field and determine if it
/// represents an integer number, a floating point number, or just arbitrary
/// string characters.
/// </summary>
public const int AUTO = 2;
/// <summary>Sort using term values as Strings. Sort values are String and lower
/// values are at the front.
/// </summary>
public const int STRING = 3;
/// <summary>Sort using term values as encoded Integers. Sort values are Integer and
/// lower values are at the front.
/// </summary>
public const int INT = 4;
/// <summary>Sort using term values as encoded Floats. Sort values are Float and
/// lower values are at the front.
/// </summary>
public const int FLOAT = 5;
/// <summary>Sort using a custom Comparator. Sort values are any Comparable and
/// sorting is done according to natural order.
/// </summary>
public const int CUSTOM = 9;
// IMPLEMENTATION NOTE: the FieldCache.STRING_INDEX is in the same "namespace"
// as the above static int values. Any new values must not have the same value
// as FieldCache.STRING_INDEX.
/// <summary>Represents sorting by document score (relevancy). </summary>
public static readonly SortField FIELD_SCORE = new SortField(null, SCORE);
/// <summary>Represents sorting by document number (index order). </summary>
public static readonly SortField FIELD_DOC = new SortField(null, DOC);
private System.String field;
private int type = AUTO; // defaults to determining type dynamically
private System.Globalization.CultureInfo locale; // defaults to "natural order" (no Locale)
internal bool reverse = false; // defaults to natural order
private SortComparatorSource factory;
/// <summary>Creates a sort by terms in the given field where the type of term value
/// is determined dynamically ({@link #AUTO AUTO}).
/// </summary>
/// <param name="field">Name of field to sort by, cannot be <code>null</code>.
/// </param>
public SortField(System.String field)
{
this.field = String.Intern(field);
}
/// <summary>Creates a sort, possibly in reverse, by terms in the given field where
/// the type of term value is determined dynamically ({@link #AUTO AUTO}).
/// </summary>
/// <param name="field">Name of field to sort by, cannot be <code>null</code>.
/// </param>
/// <param name="reverse">True if natural order should be reversed.
/// </param>
public SortField(System.String field, bool reverse)
{
this.field = String.Intern(field);
this.reverse = reverse;
}
/// <summary>Creates a sort by terms in the given field with the type of term
/// values explicitly given.
/// </summary>
/// <param name="field"> Name of field to sort by. Can be <code>null</code> if
/// <code>type</code> is SCORE or DOC.
/// </param>
/// <param name="type"> Type of values in the terms.
/// </param>
public SortField(System.String field, int type)
{
this.field = (field != null)?String.Intern(field):field;
this.type = type;
}
/// <summary>Creates a sort, possibly in reverse, by terms in the given field with the
/// type of term values explicitly given.
/// </summary>
/// <param name="field"> Name of field to sort by. Can be <code>null</code> if
/// <code>type</code> is SCORE or DOC.
/// </param>
/// <param name="type"> Type of values in the terms.
/// </param>
/// <param name="reverse">True if natural order should be reversed.
/// </param>
public SortField(System.String field, int type, bool reverse)
{
this.field = (field != null) ? String.Intern(field) : field;
this.type = type;
this.reverse = reverse;
}
/// <summary>Creates a sort by terms in the given field sorted
/// according to the given locale.
/// </summary>
/// <param name="field"> Name of field to sort by, cannot be <code>null</code>.
/// </param>
/// <param name="locale">Locale of values in the field.
/// </param>
public SortField(System.String field, System.Globalization.CultureInfo locale)
{
this.field = String.Intern(field);
this.type = STRING;
this.locale = locale;
}
/// <summary>Creates a sort, possibly in reverse, by terms in the given field sorted
/// according to the given locale.
/// </summary>
/// <param name="field"> Name of field to sort by, cannot be <code>null</code>.
/// </param>
/// <param name="locale">Locale of values in the field.
/// </param>
public SortField(System.String field, System.Globalization.CultureInfo locale, bool reverse)
{
this.field = String.Intern(field);
this.type = STRING;
this.locale = locale;
this.reverse = reverse;
}
/// <summary>Creates a sort with a custom comparison function.</summary>
/// <param name="field">Name of field to sort by; cannot be <code>null</code>.
/// </param>
/// <param name="comparator">Returns a comparator for sorting hits.
/// </param>
public SortField(System.String field, SortComparatorSource comparator)
{
this.field = (field != null)?String.Intern(field):field;
this.type = CUSTOM;
this.factory = comparator;
}
/// <summary>Creates a sort, possibly in reverse, with a custom comparison function.</summary>
/// <param name="field">Name of field to sort by; cannot be <code>null</code>.
/// </param>
/// <param name="comparator">Returns a comparator for sorting hits.
/// </param>
/// <param name="reverse">True if natural order should be reversed.
/// </param>
public SortField(System.String field, SortComparatorSource comparator, bool reverse)
{
this.field = (field != null)?String.Intern(field):field;
this.type = CUSTOM;
this.reverse = reverse;
this.factory = comparator;
}
/// <summary>Returns the name of the field. Could return <code>null</code>
/// if the sort is by SCORE or DOC.
/// </summary>
/// <returns> Name of field, possibly <code>null</code>.
/// </returns>
public virtual System.String GetField()
{
return field;
}
/// <summary>Returns the type of contents in the field.</summary>
/// <returns> One of the constants SCORE, DOC, AUTO, STRING, INT or FLOAT.
/// </returns>
public virtual int GetType()
{
return type;
}
/// <summary>Returns the Locale by which term values are interpreted.
/// May return <code>null</code> if no Locale was specified.
/// </summary>
/// <returns> Locale, or <code>null</code>.
/// </returns>
public virtual System.Globalization.CultureInfo GetLocale()
{
return locale;
}
/// <summary>Returns whether the sort should be reversed.</summary>
/// <returns> True if natural order should be reversed.
/// </returns>
public virtual bool GetReverse()
{
return reverse;
}
public virtual SortComparatorSource GetFactory()
{
return factory;
}
public override System.String ToString()
{
System.Text.StringBuilder buffer = new System.Text.StringBuilder();
switch (type)
{
case SCORE: buffer.Append("<score>");
break;
case DOC: buffer.Append("<doc>");
break;
case CUSTOM:
buffer.Append("<custom:\"" + field + "\": " + factory + ">");
break;
default: buffer.Append("\"" + field + "\"");
break;
}
if (locale != null)
buffer.Append("(" + locale + ")");
if (reverse)
buffer.Append('!');
return buffer.ToString();
}
}
}
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