package org.apache.lucene.search;
/**
* 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.
*/
import org.apache.lucene.index.IndexReader;
import java.io.IOException;
/**
* A range query that returns a constant score equal to it's boost for
* all documents in the range.
* <p>
* It does not have an upper bound on the number of clauses covered in the range.
* <p>
* If an endpoint is null, it is said to be "open".
* Either or both endpoints may be open. Open endpoints may not be exclusive
* (you can't select all but the first or last term without explicitly specifying the term to exclude.)
*
* @author yonik
* @version $Id$
*/
public class ConstantScoreRangeQuery extends Query
{
private final String fieldName;
private final String lowerVal;
private final String upperVal;
private final boolean includeLower;
private final boolean includeUpper;
public ConstantScoreRangeQuery(String fieldName, String lowerVal, String upperVal, boolean includeLower, boolean includeUpper)
{
// do a little bit of normalization...
// open ended range queries should always be inclusive.
if (lowerVal==null) {
includeLower=true;
} else if (includeLower && lowerVal.equals("")) {
lowerVal=null;
}
if (upperVal==null) {
includeUpper=true;
}
this.fieldName = fieldName.intern(); // intern it, just like terms...
this.lowerVal = lowerVal;
this.upperVal = upperVal;
this.includeLower = includeLower;
this.includeUpper = includeUpper;
}
/** Returns the field name for this query */
public String getField() { return fieldName; }
/** Returns the value of the lower endpoint of this range query, null if open ended */
public String getLowerVal() { return lowerVal; }
/** Returns the value of the upper endpoint of this range query, null if open ended */
public String getUpperVal() { return upperVal; }
/** Returns <code>true</code> if the lower endpoint is inclusive */
public boolean includesLower() { return includeLower; }
/** Returns <code>true</code> if the upper endpoint is inclusive */
public boolean includesUpper() { return includeUpper; }
public Query rewrite(IndexReader reader) throws IOException {
// Map to RangeFilter semantics which are slightly different...
RangeFilter rangeFilt = new RangeFilter(fieldName,
lowerVal!=null?lowerVal:"",
upperVal, lowerVal==""?false:includeLower, upperVal==null?false:includeUpper);
Query q = new ConstantScoreQuery(rangeFilt);
q.setBoost(getBoost());
return q;
}
/** 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(includeLower ? '[' : '{');
buffer.append(lowerVal != null ? lowerVal : "*");
buffer.append(" TO ");
buffer.append(upperVal != null ? upperVal : "*");
buffer.append(includeUpper ? ']' : '}');
if (getBoost() != 1.0f)
{
buffer.append("^");
buffer.append(Float.toString(getBoost()));
}
return buffer.toString();
}
/** Returns true if <code>o</code> is equal to this. */
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof ConstantScoreRangeQuery)) return false;
ConstantScoreRangeQuery other = (ConstantScoreRangeQuery) o;
if (this.fieldName != other.fieldName // interned comparison
|| this.includeLower != other.includeLower
|| this.includeUpper != other.includeUpper
) { return false; }
if (this.lowerVal != null ? !this.lowerVal.equals(other.lowerVal) : other.lowerVal != null) return false;
if (this.upperVal != null ? !this.upperVal.equals(other.upperVal) : other.upperVal != null) return false;
return this.getBoost() == other.getBoost();
}
/** Returns a hash code value for this object.*/
public int hashCode() {
int h = Float.floatToIntBits(getBoost()) ^ fieldName.hashCode();
// hashCode of "" is 0, so don't use that for null...
h ^= lowerVal != null ? lowerVal.hashCode() : 0x965a965a;
// don't just XOR upperVal with out mixing either it or h, as it will cancel
// out lowerVal if they are equal.
h ^= (h << 17) | (h >>> 16); // a reversible (one to one) 32 bit mapping mix
h ^= (upperVal != null ? (upperVal.hashCode()) : 0x5a695a69);
h ^= (includeLower ? 0x665599aa : 0)
^ (includeUpper ? 0x99aa5566 : 0);
return h;
}
}
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