/*
* Copyright (c) 2009-2010 Lockheed Martin Corporation
*
* 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.
*/
package org.eurekastreams.commons.search;
import java.security.InvalidParameterException;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Boosts a field in a Lucene query.
*/
public class LuceneFieldBooster
{
/**
* A list of the names of the fields allowed to be boosted.
*/
private List<String> allowableBoostFields;
/**
* Setter for allowable fields.
*
* @param inAllowableBoostFields
* the fields that are allowed to be boosted.
*/
public void setAllowableBoostFields(final List<String> inAllowableBoostFields)
{
allowableBoostFields = inAllowableBoostFields;
}
/**
* Sets a field weight, creates the field if it doens't exist.
*
* @param inFormatString
* the format string.
*
* @param fieldName
* the field.
* @param weight
* the weight.
*
* @return the formatted string.
*/
public String boostField(final String inFormatString, final String fieldName, final int weight)
{
if (!allowableBoostFields.contains(fieldName))
{
throw new InvalidParameterException("The input field name is not in the list of allowed fields.");
}
String formatString = inFormatString;
Pattern searchPattern = Pattern.compile(fieldName + ":\\(%1\\$s\\)(\\^[0-9]+)?");
Matcher patternMatcher = searchPattern.matcher(formatString);
if (patternMatcher.find())
{
formatString = patternMatcher.replaceFirst(fieldName + ":(%1\\$s)^" + weight);
}
else
{
formatString += " " + fieldName + ":(%1$s)^" + weight;
}
return formatString;
}
}