CustomDateTimePatternManager.java

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// Copyright (C) 2006-2016 Talend Inc. - www.talend.com
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package org.talend.dataquality.statistics.datetime;

import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeParseException;
import java.time.temporal.TemporalAccessor;
import java.time.temporal.TemporalQueries;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;

/**
 * Customized date time pattern manager.
 * 
 * @author mzhao
 *
 */
public final class CustomDateTimePatternManager {

    private static final Locale DEFAULT_LOCALE = Locale.US;

    private static Map<String, DateTimeFormatter> dateTimeFormatterCache = new HashMap<String, DateTimeFormatter>();

    public static boolean isDate(String value, List<String> customPatterns) {
        return isDate(value, customPatterns, DEFAULT_LOCALE);
    }

    public static boolean isDate(String value, List<String> customPatterns, Locale locale) {
        // use custom patterns first
        if (isMatchCustomPatterns(value, customPatterns, locale)) {
            return true;
        }
        // validate using system pattern manager
        return SystemDateTimePatternManager.isDate(value);
    }

    public static boolean isTime(String value, List<String> customPatterns) {
        return isTime(value, customPatterns, DEFAULT_LOCALE);
    }

    public static boolean isTime(String value, List<String> customPatterns, Locale locale) {
        // use custom patterns first
        if (isMatchCustomPatterns(value, customPatterns, locale)) {
            return true;
        }
        // validate using system pattern manager
        return SystemDateTimePatternManager.isTime(value);
    }

    private static boolean isMatchCustomPatterns(String value, List<String> customPatterns, Locale locale) {
        for (String pattern : customPatterns) {
            if (isMatchCustomPattern(value, pattern, locale)) {
                return true;
            }
        }
        return false;
    }

    private static DateTimeFormatter getDateTimeFormatterByPattern(String customPattern, Locale locale) {
        String localeStr = locale.toString();
        DateTimeFormatter formatter = dateTimeFormatterCache.get(customPattern + localeStr);
        if (formatter == null) {
            try {
                formatter = DateTimeFormatter.ofPattern(customPattern, locale);
            } catch (IllegalArgumentException e) {
                return null;
            }
            dateTimeFormatterCache.put(customPattern + localeStr, formatter);
        }
        return formatter;
    }

    private static boolean isMatchCustomPattern(String value, String customPattern, Locale locale) {
        if (customPattern == null) {
            return false;
        }

        try {// firstly, try with user-defined locale
            final DateTimeFormatter formatter = getDateTimeFormatterByPattern(customPattern, locale);
            if (formatter != null) {
                final TemporalAccessor temporal = formatter.parse(value);
                if (temporal.query(TemporalQueries.localDate()) != null || temporal.query(TemporalQueries.localTime()) != null) {
                    return true;
                }
            }
        } catch (DateTimeParseException e) {
            if (!DEFAULT_LOCALE.equals(locale)) {
                try {// try with LOCALE_US if user defined locale is not US
                    final DateTimeFormatter formatter = getDateTimeFormatterByPattern(customPattern, Locale.US);
                    if (formatter != null) {
                        final TemporalAccessor temporal = formatter.parse(value);
                        if (temporal.query(TemporalQueries.localDate()) != null
                                || temporal.query(TemporalQueries.localTime()) != null) {
                            return true;
                        }
                    }
                } catch (DateTimeParseException e2) {
                    // return false
                }
            }
        }
        return false;
    }

    // for junit only
    static Set<String> replaceByDateTimePattern(String value, String customPattern) {
        return replaceByDateTimePattern(value, customPattern, DEFAULT_LOCALE);
    }

    static Set<String> replaceByDateTimePattern(String value, String customPattern, Locale locale) {
        return replaceByDateTimePattern(value, Collections.singletonList(customPattern), locale);
    }

    public static Set<String> replaceByDateTimePattern(String value, List<String> customPatterns) {
        return replaceByDateTimePattern(value, customPatterns, DEFAULT_LOCALE);
    }

    public static Set<String> replaceByDateTimePattern(String value, List<String> customPatterns, Locale locale) {
        Set<String> resultPatternSet = new HashSet<String>();
        for (String customPattern : customPatterns) {
            if (isMatchCustomPattern(value, customPattern, locale)) {
                resultPatternSet.add(customPattern);
            }
        }
        // otherwise, replace with system date pattern manager.
        resultPatternSet.addAll(systemPatternReplace(value));
        return resultPatternSet;
    }

    private static Set<String> systemPatternReplace(String value) {
        Set<String> resultPatternSet = new HashSet<String>();
        resultPatternSet.addAll(SystemDateTimePatternManager.datePatternReplace(value));
        if (resultPatternSet.isEmpty()) {
            resultPatternSet.addAll(SystemDateTimePatternManager.timePatternReplace(value));
        }
        return resultPatternSet;
    }
}