org.apache.metron.common.field.transformation.RegexSelectTransformation.java Source code

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Here is the source code for org.apache.metron.common.field.transformation.RegexSelectTransformation.java

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/**
 * 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.metron.common.field.transformation;

import com.google.common.collect.Iterables;
import org.apache.metron.stellar.common.utils.PatternCache;
import org.apache.metron.stellar.dsl.Context;

import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

public class RegexSelectTransformation implements FieldTransformation {
    @Override
    public Map<String, Object> map(Map<String, Object> input, List<String> outputField,
            LinkedHashMap<String, Object> fieldMappingConfig, Context context,
            Map<String, Object>... sensorConfig) {
        String outField = null;
        if (!(outputField == null || outputField.isEmpty())) {
            outField = outputField.get(0);
        }
        String inVal = null;
        if (!(input == null || input.isEmpty() || input.size() > 1)) {
            Object inValObj = Iterables.getFirst(input.entrySet(), null).getValue();
            if (inValObj != null) {
                inVal = inValObj.toString();
            }
        }
        Map<String, Object> ret = new HashMap<>(1);
        if (outField == null || inVal == null) {
            //in the situation where we don't have valid input or output, then we want to do nothing
            return ret;
        }
        for (Map.Entry<String, Object> valToRegex : fieldMappingConfig.entrySet()) {
            if (isMatch(valToRegex.getValue(), inVal)) {
                ret.put(outField, valToRegex.getKey());
                break;
            }
        }
        return ret;
    }

    /**
     * Return true if there is a regex match or false otherwise.
     * @param regexes This could be either a list of regexes or a single regex
     * @param field The field to match
     * @return
     */
    private static boolean isMatch(Object regexes, String field) {
        if (regexes instanceof String) {
            return isMatch((String) regexes, field);
        } else if (regexes instanceof List) {
            for (Object regex : (List) regexes) {
                if (isMatch(regex.toString(), field)) {
                    return true;
                }
            }
        }
        return false;
    }

    private static boolean isMatch(String regex, String field) {
        try {
            Pattern p = PatternCache.INSTANCE.getPattern(regex);
            if (p == null) {
                return false;
            }
            return p.asPredicate().test(field);
        } catch (PatternSyntaxException pse) {
            return false;
        }
    }

}