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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 Term = Lucene.Net.Index.Term;
using TermEnum = Lucene.Net.Index.TermEnum;
using IndexReader = Lucene.Net.Index.IndexReader;
using ToStringUtils = Lucene.Net.Util.ToStringUtils;
namespace Lucene.Net.Search
{
/// <summary> A Query that matches documents within an exclusive range. A RangeQuery
/// is built by QueryParser for input like <code>[010 TO 120]</code> but only if the QueryParser has
/// the useOldRangeQuery property set to true. The QueryParser default behaviour is to use
/// the newer ConstantScoreRangeQuery class. This is generally preferable because:
/// <ul>
/// <li>It is faster than RangeQuery</li>
/// <li>Unlike RangeQuery, it does not cause a BooleanQuery.TooManyClauses exception if the range of values is large</li>
/// <li>Unlike RangeQuery it does not influence scoring based on the scarcity of individual terms that may match</li>
/// </ul>
///
///
/// </summary>
/// <seealso cref="ConstantScoreRangeQuery">
///
///
/// </seealso>
/// <version> $Id: RangeQuery.java 520891 2007-03-21 13:58:47Z yonik $
/// </version>
[Serializable]
public class RangeQuery : Query
{
private Term lowerTerm;
private Term upperTerm;
private bool inclusive;
/// <summary>Constructs a query selecting all terms greater than
/// <code>lowerTerm</code> but less than <code>upperTerm</code>.
/// There must be at least one term and either term may be null,
/// in which case there is no bound on that side, but if there are
/// two terms, both terms <b>must</b> be for the same field.
/// </summary>
public RangeQuery(Term lowerTerm, Term upperTerm, bool inclusive)
{
if (lowerTerm == null && upperTerm == null)
{
throw new System.ArgumentException("At least one term must be non-null");
}
if (lowerTerm != null && upperTerm != null && lowerTerm.Field() != upperTerm.Field())
{
throw new System.ArgumentException("Both terms must be for the same field");
}
// if we have a lowerTerm, start there. otherwise, start at beginning
if (lowerTerm != null)
{
this.lowerTerm = lowerTerm;
}
else
{
this.lowerTerm = new Term(upperTerm.Field(), "");
}
this.upperTerm = upperTerm;
this.inclusive = inclusive;
}
public override Query Rewrite(IndexReader reader)
{
BooleanQuery query = new BooleanQuery(true);
TermEnum enumerator = reader.Terms(lowerTerm);
try
{
bool checkLower = false;
if (!inclusive)
// make adjustments to set to exclusive
checkLower = true;
System.String testField = GetField();
do
{
Term term = enumerator.Term();
if (term != null && term.Field() == testField)
{
// interned comparison
if (!checkLower || String.CompareOrdinal(term.Text(), lowerTerm.Text()) > 0)
{
checkLower = false;
if (upperTerm != null)
{
int compare = String.CompareOrdinal(upperTerm.Text(), term.Text());
/* if beyond the upper term, or is exclusive and
* this is equal to the upper term, break out */
if ((compare < 0) || (!inclusive && compare == 0))
break;
}
TermQuery tq = new TermQuery(term); // found a match
tq.SetBoost(GetBoost()); // set the boost
query.Add(tq, BooleanClause.Occur.SHOULD); // add to query
}
}
else
{
break;
}
}
while (enumerator.Next());
}
finally
{
enumerator.Close();
}
return query;
}
/// <summary>Returns the field name for this query </summary>
public virtual System.String GetField()
{
return (lowerTerm != null ? lowerTerm.Field() : upperTerm.Field());
}
/// <summary>Returns the lower term of this range query </summary>
public virtual Term GetLowerTerm()
{
return lowerTerm;
}
/// <summary>Returns the upper term of this range query </summary>
public virtual Term GetUpperTerm()
{
return upperTerm;
}
/// <summary>Returns <code>true</code> if the range query is inclusive </summary>
public virtual bool IsInclusive()
{
return inclusive;
}
/// <summary>Prints a user-readable version of this query. </summary>
public override System.String ToString(System.String field)
{
System.Text.StringBuilder buffer = new System.Text.StringBuilder();
if (!GetField().Equals(field))
{
buffer.Append(GetField());
buffer.Append(":");
}
buffer.Append(inclusive ? "[" : "{");
buffer.Append(lowerTerm != null ? lowerTerm.Text() : "null");
buffer.Append(" TO ");
buffer.Append(upperTerm != null ? upperTerm.Text() : "null");
buffer.Append(inclusive ? "]" : "}");
buffer.Append(ToStringUtils.Boost(GetBoost()));
return buffer.ToString();
}
/// <summary>Returns true iff <code>o</code> is equal to this. </summary>
public override bool Equals(System.Object o)
{
if (this == o)
return true;
if (!(o is RangeQuery))
return false;
RangeQuery other = (RangeQuery) o;
if (this.GetBoost() != other.GetBoost())
return false;
if (this.inclusive != other.inclusive)
return false;
// one of lowerTerm and upperTerm can be null
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 = BitConverter.ToInt32(BitConverter.GetBytes(GetBoost()), 0);
h ^= (lowerTerm != null ? lowerTerm.GetHashCode() : 0);
// reversible mix to make lower and upper position dependent and
// to prevent them from cancelling out.
h ^= ((h << 25) | (h >> 8));
h ^= (upperTerm != null ? upperTerm.GetHashCode() : 0);
h ^= (this.inclusive ? 0x2742E74A : 0);
return h;
}
}
}
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