001/*
002 * Copyright (c) 2015-2020, Oracle and/or its affiliates. All rights reserved.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.tribuo.data.columnar.extractors;
018
019import com.oracle.labs.mlrg.olcut.provenance.ConfiguredObjectProvenance;
020import com.oracle.labs.mlrg.olcut.provenance.impl.ConfiguredObjectProvenanceImpl;
021
022import java.util.Optional;
023import java.util.logging.Logger;
024
025/**
026 * Extracts the field value and converts it to a double.
027 * <p>
028 * Returns an empty optional if the value failed to parse.
029 */
030public class DoubleExtractor extends SimpleFieldExtractor<Double> {
031    private static final Logger logger = Logger.getLogger(DoubleExtractor.class.getName());
032
033    /**
034     * Extracts a double value from the supplied field name.
035     * Writes the metadata out using the field name as the key.
036     * @param fieldName The field name to inspect.
037     */
038    public DoubleExtractor(String fieldName) {
039        super(fieldName);
040    }
041
042    /**
043     * Extracts a double value from the supplied field name.
044     * Writes the metadata out using the metadataName as the key.
045     * @param fieldName The field name to inspect.
046     * @param metadataName The metadata name to emit.
047     */
048    public DoubleExtractor(String fieldName, String metadataName) {
049        super(fieldName, metadataName);
050    }
051
052    /**
053     * For olcut.
054     */
055    private DoubleExtractor() {}
056
057    @Override
058    public Class<Double> getValueType() {
059        return Double.class;
060    }
061
062    @Override
063    protected Optional<Double> extractField(String value) {
064        try {
065            double f = Double.parseDouble(value);
066            return Optional.of(f);
067        } catch (NumberFormatException e) {
068            logger.warning("Failed to parse value for field " + fieldName + ", expected a double, got " + value);
069        }
070        return Optional.empty();
071    }
072
073    @Override
074    public ConfiguredObjectProvenance getProvenance() {
075        return new ConfiguredObjectProvenanceImpl(this,"FieldExtractor");
076    }
077}