Java Parse Date parseDate(String dateText)

Description

parse Date

License

Apache License

Declaration

public static Date parseDate(String dateText) 

Method Source Code

//package com.java2s;
/*/* ww w  .j  ava 2s  . c o  m*/
 * Copyright 2015 Boleslav Bobcik - Auderis
 *
 * Licensed 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.
 */

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
    static final Pattern FULL_ISO_PATTERN = Pattern
            .compile("\\d{4}-\\d{2}-\\d{2}([T ])\\d{2}:\\d{2}:\\d{2}((?:\\.\\d{3})?)");
    static final Pattern COMPACT_ISO_PATTERN = Pattern
            .compile("\\d{4}(-?)\\d{2}\\1\\d{2}([T ]?)\\d{2}(:?)\\d{2}\\3\\d{2}");
    static final Pattern DATE_ISO_PATTERN = Pattern.compile("\\d{4}(-?)\\d{2}\\1\\d{2}");

    public static Date parseDate(String dateText) {
        return parseDate(dateText, null);
    }

    public static Date parseDate(String dateText, String optionalCustomFormat) {
        if (null == dateText) {
            throw new NullPointerException();
        } else if (dateText.trim().isEmpty()) {
            return null;
        }
        final DateFormat format = determineDatePattern(dateText, optionalCustomFormat);
        try {
            return format.parse(dateText);
        } catch (ParseException e) {
            throw new IllegalArgumentException("Cannot parse date '" + dateText + "'", e);
        }
    }

    public static DateFormat determineDatePattern(String textParam, String options) {
        final DateFormat format;
        if ((null != options) && !options.trim().isEmpty()) {
            // Use user-specified pattern
            format = new SimpleDateFormat(options);
        } else {
            format = recognizeStandardDatePattern(textParam);
        }
        return format;
    }

    private static DateFormat recognizeStandardDatePattern(String textParam) {
        final StringBuilder formatBuilder = new StringBuilder(32);
        final Matcher matcher = FULL_ISO_PATTERN.matcher(textParam);
        if (matcher.matches()) {
            formatBuilder.append("yyyy-MM-dd");
            final String dateTimeSeparator = matcher.group(1);
            formatBuilder.append('\'').append(dateTimeSeparator).append('\'');
            formatBuilder.append("HH:mm:ss");
            final String millisPart = matcher.group(2);
            if ((null != millisPart) && !millisPart.isEmpty()) {
                formatBuilder.append(".SSS");
            }
            return new SimpleDateFormat(formatBuilder.toString());
        }
        //
        matcher.usePattern(COMPACT_ISO_PATTERN).reset();
        if (matcher.matches()) {
            final String datePartSeparator = matcher.group(1);
            formatBuilder.append("yyyy");
            formatBuilder.append(datePartSeparator).append("MM");
            formatBuilder.append(datePartSeparator).append("dd");
            final String dateTimeSeparator = matcher.group(2);
            if (!dateTimeSeparator.isEmpty()) {
                formatBuilder.append('\'').append(dateTimeSeparator).append('\'');
            }
            final String timePartSeparator = matcher.group(3);
            formatBuilder.append("HH");
            formatBuilder.append(timePartSeparator).append("mm");
            formatBuilder.append(timePartSeparator).append("ss");
            return new SimpleDateFormat(formatBuilder.toString());
        }
        //
        matcher.usePattern(DATE_ISO_PATTERN).reset();
        if (matcher.matches()) {
            final String datePartSeparator = matcher.group(1);
            formatBuilder.append("yyyy");
            formatBuilder.append(datePartSeparator).append("MM");
            formatBuilder.append(datePartSeparator).append("dd");
            return new SimpleDateFormat(formatBuilder.toString());
        }
        //
        throw new IllegalArgumentException("Cannot determine date format of '" + textParam + "'");
    }
}

Related

1. parseDate(String dateString, Locale locale)
2. parseDate(String dateString, SimpleDateFormat simpleDateFormat)
3. parseDate(String dateString, String dateFormat)
4. parseDate(String dateString, String format, TimeZone zone)
5. parseDate(String dateString, String pattern)
6. parseDate(String datetime)
7. parseDate(String dateVal)
8. parseDate(String dateValue)
9. parseDate(String dateValue)