package org.apache.lucene.search;
/**
* 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.
*/
import java.io.IOException;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermEnum;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.util.ToStringUtils;
/**
* 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>
*
*
* @see ConstantScoreRangeQuery
*
*
* @version $Id: RangeQuery.java 475435 2006-11-15 21:26:09Z mharwood $
*/
public class RangeQuery extends Query
{
private Term lowerTerm;
private Term upperTerm;
private boolean inclusive;
/** 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.
*/
public RangeQuery(Term lowerTerm, Term upperTerm, boolean inclusive)
{
if (lowerTerm == null && upperTerm == null)
{
throw new IllegalArgumentException("At least one term must be non-null");
}
if (lowerTerm != null && upperTerm != null && lowerTerm.field() != upperTerm.field())
{
throw new IllegalArgumentException("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 Query rewrite(IndexReader reader) throws IOException {
BooleanQuery query = new BooleanQuery(true);
TermEnum enumerator = reader.terms(lowerTerm);
try {
boolean checkLower = false;
if (!inclusive) // make adjustments to set to exclusive
checkLower = true;
String testField = getField();
do {
Term term = enumerator.term();
if (term != null && term.field() == testField) {
if (!checkLower || term.text().compareTo(lowerTerm.text()) > 0) {
checkLower = false;
if (upperTerm != null) {
int compare = upperTerm.text().compareTo(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;
}
/** Returns the field name for this query */
public String getField() {
return (lowerTerm != null ? lowerTerm.field() : upperTerm.field());
}
/** Returns the lower term of this range query */
public Term getLowerTerm() { return lowerTerm; }
/** Returns the upper term of this range query */
public Term getUpperTerm() { return upperTerm; }
/** Returns <code>true</code> if the range query is inclusive */
public boolean isInclusive() { return inclusive; }
/** Prints a user-readable version of this query. */
public String toString(String field)
{
StringBuffer buffer = new StringBuffer();
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();
}
/** Returns true iff <code>o</code> is equal to this. */
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof RangeQuery)) return false;
final 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;
}
/** Returns a hash code value for this object.*/
public int hashCode() {
int h = Float.floatToIntBits(getBoost());
h ^= lowerTerm != null ? lowerTerm.hashCode() : 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.hashCode() : 0;
h ^= this.inclusive ? 0x2742E74A : 0;
return h;
}
}
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