org.apache.metron.common.field.FieldNameConverters.java Source code

Introduction

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

Source

/*
 * 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;

import org.apache.commons.lang.ClassUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.lang3.exception.ExceptionUtils;
import org.apache.metron.common.configuration.writer.WriterConfiguration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.lang.invoke.MethodHandles;

/**
 * Enumerates a set of {@link FieldNameConverter} implementations.
 *
 * <p>Provides shared instances of each {@link FieldNameConverter}.
 *
 * <p>Allows the field name converter to be specified using a short-hand
 * name, rather than the entire fully-qualified class name.
 */
public enum FieldNameConverters implements FieldNameConverter {

    /**
     * A {@link FieldNameConverter} that does not rename any fields.  All field
     * names remain unchanged.
     */
    NOOP(new NoopFieldNameConverter()),

    /**
     * A {@link FieldNameConverter} that replaces all field names containing dots
     * with colons.
     */
    DEDOT(new DeDotFieldNameConverter());

    private static final Logger LOG = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());

    private FieldNameConverter converter;

    FieldNameConverters(FieldNameConverter converter) {
        this.converter = converter;
    }

    /**
     * Returns a shared instance of the {@link FieldNameConverter}/
     *
     * @return A shared {@link FieldNameConverter} instance.
     */
    public FieldNameConverter get() {
        return converter;
    }

    /**
     * Allows the {@link FieldNameConverters} enums to be used directly as a {@link FieldNameConverter}.
     *
     * {@code
     * FieldNameConverter converter = FieldNameConverters.DEDOT;
     * }
     *
     * @param originalField The original field name.
     * @return
     */
    @Override
    public String convert(String originalField) {
        return converter.convert(originalField);
    }

    /**
     * Create a new {@link FieldNameConverter}.
     *
     * @param sensorType The type of sensor.
     * @param config The writer configuration.
     * @return
     */
    public static FieldNameConverter create(String sensorType, WriterConfiguration config) {
        FieldNameConverter result = null;

        // which field name converter has been configured?
        String converterName = config.getFieldNameConverter(sensorType);
        if (StringUtils.isNotBlank(converterName)) {
            try {
                result = FieldNameConverters.valueOf(converterName);

            } catch (IllegalArgumentException e) {
                LOG.error("Invalid field name converter, using default; configured={}, knownValues={}, error={}",
                        converterName, FieldNameConverters.values(), ExceptionUtils.getRootCauseMessage(e));
            }
        }

        if (result == null) {
            // if no converter defined or an invalid converter is defined, default to 'DEDOT'
            result = FieldNameConverters.DEDOT;
        }

        LOG.debug("Created field name converter; sensorType={}, configured={}, class={}", sensorType, converterName,
                ClassUtils.getShortClassName(result, "null"));

        return result;
    }
}