/*
* 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.nifi.attribute.expression.language.evaluation.selection;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.regex.Pattern;
import org.apache.nifi.attribute.expression.language.evaluation.Evaluator;
import org.apache.nifi.attribute.expression.language.evaluation.QueryResult;
import org.apache.nifi.attribute.expression.language.evaluation.StringQueryResult;
public class MultiMatchAttributeEvaluator extends MultiAttributeEvaluator {
private final List<Pattern> attributePatterns;
private final int evaluationType;
private final List<String> attributeNames = new ArrayList<>();
private int evaluationCount = 0;
public MultiMatchAttributeEvaluator(final List<String> attributeRegexes, final int evaluationType) {
this.attributePatterns = new ArrayList<>();
for (final String regex : attributeRegexes) {
attributePatterns.add(Pattern.compile(regex));
}
this.evaluationType = evaluationType;
}
/**
* Can be called only after the first call to evaluate
*
* @return number of remaining evaluations
*/
@Override
public int getEvaluationsRemaining() {
return attributeNames.size() - evaluationCount;
}
@Override
public QueryResult<String> evaluate(final Map<String, String> attributes) {
if (evaluationCount == 0) {
for (final Pattern pattern : attributePatterns) {
for (final String attrName : attributes.keySet()) {
if (pattern.matcher(attrName).matches()) {
attributeNames.add(attrName);
}
}
}
}
if (evaluationCount >= attributeNames.size()) {
return new StringQueryResult(null);
}
return new StringQueryResult(attributes.get(attributeNames.get(evaluationCount++)));
}
@Override
public Evaluator<?> getSubjectEvaluator() {
return null;
}
@Override
public int getEvaluationType() {
return evaluationType;
}
@Override
public Evaluator<?> getLogicEvaluator() {
return this;
}
}