/*
* 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;
using IndexReaderLucene.Net.Index.IndexReader;
using TermLucene.Net.Index.Term;
using TermDocsLucene.Net.Index.TermDocs;
using TermEnumLucene.Net.Index.TermEnum;
namespace Lucene.Net.Search{
/// <summary> A Filter that restricts search results to a range of values in a given
/// field.
///
/// <p>
/// This code borrows heavily from {@link RangeQuery}, but is implemented as a Filter
/// (much like {@link DateFilter}).
/// </p>
/// </summary>
[Serializable]
public class RangeFilter : Filter
{
private System.String fieldName;
private System.String lowerTerm;
private System.String upperTerm;
private bool includeLower;
private bool includeUpper;
/// <param name="fieldName">The field this range applies to
/// </param>
/// <param name="lowerTerm">The lower bound on this range
/// </param>
/// <param name="upperTerm">The upper bound on this range
/// </param>
/// <param name="includeLower">Does this range include the lower bound?
/// </param>
/// <param name="includeUpper">Does this range include the upper bound?
/// </param>
/// <throws> IllegalArgumentException if both terms are null or if </throws>
/// <summary> lowerTerm is null and includeLower is true (similar for upperTerm
/// and includeUpper)
/// </summary>
public RangeFilter(System.String fieldName, System.String lowerTerm, System.String upperTerm, bool includeLower, bool includeUpper)
{
this.fieldName = fieldName;
this.lowerTerm = lowerTerm;
this.upperTerm = upperTerm;
this.includeLower = includeLower;
this.includeUpper = includeUpper;
if (null == lowerTerm && null == upperTerm)
{
throw new System.ArgumentException("At least one value must be non-null");
}
if (includeLower && null == lowerTerm)
{
throw new System.ArgumentException("The lower bound must be non-null to be inclusive");
}
if (includeUpper && null == upperTerm)
{
throw new System.ArgumentException("The upper bound must be non-null to be inclusive");
}
}
/// <summary> Constructs a filter for field <code>fieldName</code> matching
/// less than or equal to <code>upperTerm</code>.
/// </summary>
public static RangeFilter Less(System.String fieldName, System.String upperTerm)
{
return new RangeFilter(fieldName, null, upperTerm, false, true);
}
/// <summary> Constructs a filter for field <code>fieldName</code> matching
/// greater than or equal to <code>lowerTerm</code>.
/// </summary>
public static RangeFilter More(System.String fieldName, System.String lowerTerm)
{
return new RangeFilter(fieldName, lowerTerm, null, true, false);
}
/// <summary> Returns a BitSet with true for documents which should be
/// permitted in search results, and false for those that should
/// not.
/// </summary>
public override System.Collections.BitArray Bits(IndexReader reader)
{
System.Collections.BitArray bits = new System.Collections.BitArray((reader.MaxDoc() % 64 == 0?reader.MaxDoc() / 64:reader.MaxDoc() / 64 + 1) * 64);
TermEnum enumerator = (null != lowerTerm?reader.Terms(new Term(fieldName, lowerTerm)):reader.Terms(new Term(fieldName, "")));
try
{
if (enumerator.Term() == null)
{
return bits;
}
bool checkLower = false;
if (!includeLower)
// make adjustments to set to exclusive
checkLower = true;
TermDocs termDocs = reader.TermDocs();
try
{
do
{
Term term = enumerator.Term();
if (term != null && term.Field().Equals(fieldName))
{
if (!checkLower || null == lowerTerm || String.CompareOrdinal(term.Text(), lowerTerm) > 0)
{
checkLower = false;
if (upperTerm != null)
{
int compare = String.CompareOrdinal(upperTerm, term.Text());
/* if beyond the upper term, or is exclusive and
* this is equal to the upper term, break out */
if ((compare < 0) || (!includeUpper && compare == 0))
{
break;
}
}
/* we have a good term, find the docs */
termDocs.Seek(enumerator.Term());
while (termDocs.Next())
{
bits.Set(termDocs.Doc(), true);
}
}
}
else
{
break;
}
}
while (enumerator.Next());
}
finally
{
termDocs.Close();
}
}
finally
{
enumerator.Close();
}
return bits;
}
public override System.String ToString()
{
System.Text.StringBuilder buffer = new System.Text.StringBuilder();
buffer.Append(fieldName);
buffer.Append(":");
buffer.Append(includeLower?"[":"{");
if (null != lowerTerm)
{
buffer.Append(lowerTerm);
}
buffer.Append("-");
if (null != upperTerm)
{
buffer.Append(upperTerm);
}
buffer.Append(includeUpper ? "]" : "}");
return buffer.ToString();
}
/// <summary>Returns true if <code>o</code> is equal to this. </summary>
public override bool Equals(System.Object o)
{
if (this == o)
return true;
if (!(o is RangeFilter))
return false;
RangeFilter other = (RangeFilter) o;
if (!this.fieldName.Equals(other.fieldName) || this.includeLower != other.includeLower || this.includeUpper != other.includeUpper)
{
return false;
}
if (this.lowerTerm != null ? !this.lowerTerm.Equals(other.lowerTerm) : other.lowerTerm != null)
return false;
if (this.upperTerm != null ? !this.upperTerm.Equals(other.upperTerm) : other.upperTerm != null)
return false;
return true;
}
/// <summary>Returns a hash code value for this object.</summary>
public override int GetHashCode()
{
int h = fieldName.GetHashCode();
h ^= (lowerTerm != null ? lowerTerm.GetHashCode() : unchecked((int) 0xB6ECE882)); // {{Aroush-1.9}} is this OK?!
h = (h << 1) | (SupportClass.Number.URShift(h, 31)); // rotate to distinguish lower from upper
h ^= (upperTerm != null ? (upperTerm.GetHashCode()) : unchecked((int) 0x91BEC2C2)); // {{Aroush-1.9}} is this OK?!
h ^= (includeLower ? unchecked((int) 0xD484B933) : 0) ^ (includeUpper ? 0x6AE423AC : 0); // {{Aroush-1.9}} is this OK?!
return h;
}
}
}
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