/*
* 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.
*/
package org.apache.solr.ltr;
/**
* A feature logger that logs in csv format.
*/
public class CSVFeatureLogger extends FeatureLogger {
public static final char DEFAULT_KEY_VALUE_SEPARATOR = '=';
public static final char DEFAULT_FEATURE_SEPARATOR = ',';
private final char keyValueSep;
private final char featureSep;
public CSVFeatureLogger(String fvCacheName, FeatureFormat f) {
super(fvCacheName, f);
this.keyValueSep = DEFAULT_KEY_VALUE_SEPARATOR;
this.featureSep = DEFAULT_FEATURE_SEPARATOR;
}
public CSVFeatureLogger(String fvCacheName, FeatureFormat f, char keyValueSep, char featureSep) {
super(fvCacheName, f);
this.keyValueSep = keyValueSep;
this.featureSep = featureSep;
}
@Override
public String makeFeatureVector(LTRScoringQuery.FeatureInfo[] featuresInfo) {
// Allocate the buffer to a size based on the number of features instead of the
// default 16. You need space for the name, value, and two separators per feature,
// but not all the features are expected to fire, so this is just a naive estimate.
StringBuilder sb = new StringBuilder(featuresInfo.length * 3);
boolean isDense = featureFormat.equals(FeatureFormat.DENSE);
for (LTRScoringQuery.FeatureInfo featInfo:featuresInfo) {
if (featInfo.isUsed() || isDense){
sb.append(featInfo.getName())
.append(keyValueSep)
.append(featInfo.getValue())
.append(featureSep);
}
}
final String features = (sb.length() > 0 ?
sb.substring(0, sb.length() - 1) : "");
return features;
}
}