/*
    * 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.commons.validator.routines;
  
  import java.text.DateFormat;
  import java.text.Format;
  import java.util.Calendar;
  import java.util.Locale;
  import java.util.TimeZone;
  
  /**
   * <p><b>Calendar Validation</b> and Conversion routines (<code>java.util.Calendar</code>).</p>
   *
   * <p>This validator provides a number of methods for validating/converting
   *    a <code>String</code> date value to a <code>java.util.Calendar</code> using
   *    <code>java.text.DateFormat</code> to parse either:</p>
   *    <ul>
   *       <li>using the default format for the default <code>Locale</code></li>
   *       <li>using a specified pattern with the default <code>Locale</code></li>
   *       <li>using the default format for a specified <code>Locale</code></li>
   *       <li>using a specified pattern with a specified <code>Locale</code></li>
   *    </ul>
   *
   * <p>For each of the above mechanisms, conversion method (i.e the
   *    <code>validate</code> methods) implementations are provided which
   *    either use the default <code>TimeZone</code> or allow the
   *    <code>TimeZone</code> to be specified.</p>
   *
   * <p>Use one of the <code>isValid()</code> methods to just validate or
   *    one of the <code>validate()</code> methods to validate and receive a
   *    <i>converted</i> <code>Calendar</code> value.</p>
   *
   * <p>Implementations of the <code>validate()</code> method are provided
   *    to create <code>Calendar</code> objects for different <i>time zones</i>
   *    if the system default is not appropriate.</p>
   *
   * <p>Alternatively the CalendarValidator's <code>adjustToTimeZone()</code> method
   *    can be used to adjust the <code>TimeZone</code> of the <code>Calendar</code>
   *    object afterwards.</p>
   *
   * <p>Once a value has been successfully converted the following
   *    methods can be used to perform various date comparison checks:</p>
   *    <ul>
   *       <li><code>compareDates()</code> compares the day, month and
   *           year of two calendars, returning 0, -1 or +1 indicating
   *           whether the first date is equal, before or after the second.</li>
   *       <li><code>compareWeeks()</code> compares the week and
   *           year of two calendars, returning 0, -1 or +1 indicating
   *           whether the first week is equal, before or after the second.</li>
   *       <li><code>compareMonths()</code> compares the month and
   *           year of two calendars, returning 0, -1 or +1 indicating
   *           whether the first month is equal, before or after the second.</li>
   *       <li><code>compareQuarters()</code> compares the quarter and
   *           year of two calendars, returning 0, -1 or +1 indicating
   *           whether the first quarter is equal, before or after the second.</li>
   *       <li><code>compareYears()</code> compares the
   *           year of two calendars, returning 0, -1 or +1 indicating
   *           whether the first year is equal, before or after the second.</li>
   *    </ul>
   *
   * <p>So that the same mechanism used for parsing an <i>input</i> value
   *    for validation can be used to format <i>output</i>, corresponding
   *    <code>format()</code> methods are also provided. That is you can
   *    format either:</p>
   *    <ul>
   *       <li>using a specified pattern</li>
   *       <li>using the format for a specified <code>Locale</code></li>
   *       <li>using the format for the <i>default</i> <code>Locale</code></li>
   *    </ul>
   *
   * @since 1.3.0
   */
  public class CalendarValidator extends AbstractCalendarValidator {
  
      private static final long serialVersionUID = 9109652318762134167L;
  
      private static final CalendarValidator VALIDATOR = new CalendarValidator();
  
      /**
       * <p>Adjusts a Calendar's value to a different TimeZone.</p>
       *
       * @param value The value to adjust.
       * @param timeZone The new time zone to use to adjust the Calendar to.
       */
      public static void adjustToTimeZone(final Calendar value, final TimeZone timeZone) {
         if (value.getTimeZone().hasSameRules(timeZone)) {
             value.setTimeZone(timeZone);
         } else {
             final int year = value.get(Calendar.YEAR);
             final int month = value.get(Calendar.MONTH);
             final int date = value.get(Calendar.DATE);
             final int hour = value.get(Calendar.HOUR_OF_DAY);
             final int minute = value.get(Calendar.MINUTE);
             value.setTimeZone(timeZone);
             value.set(year, month, date, hour, minute);
         }
     }
 
     /**
      * Gets the singleton instance of this validator.
      * @return A singleton instance of the CalendarValidator.
      */
     public static CalendarValidator getInstance() {
         return VALIDATOR;
     }
 
     /**
      * Constructs a <i>strict</i> instance with <i>short</i>
      * date style.
      */
     public CalendarValidator() {
         this(true, DateFormat.SHORT);
     }
 
     /**
      * Constructs an instance with the specified <i>strict</i>
      * and <i>date style</i> parameters.
      *
      * @param strict {@code true} if strict
      *        <code>Format</code> parsing should be used.
      * @param dateStyle the date style to use for Locale validation.
      */
     public CalendarValidator(final boolean strict, final int dateStyle) {
         super(strict, dateStyle, -1);
     }
 
     /**
      * <p>Compare Dates (day, month and year - not time).</p>
      *
      * @param value The <code>Calendar</code> value to check.
      * @param compare The <code>Calendar</code> to compare the value to.
      * @return Zero if the dates are equal, -1 if first
      * date is less than the seconds and +1 if the first
      * date is greater than.
      */
     public int compareDates(final Calendar value, final Calendar compare) {
         return compare(value, compare, Calendar.DATE);
     }
 
     /**
      * <p>Compare Months (month and year).</p>
      *
      * @param value The <code>Calendar</code> value to check.
      * @param compare The <code>Calendar</code> to compare the value to.
      * @return Zero if the months are equal, -1 if first
      * parameter's month is less than the seconds and +1 if the first
      * parameter's month is greater than.
      */
     public int compareMonths(final Calendar value, final Calendar compare) {
         return compare(value, compare, Calendar.MONTH);
     }
 
     /**
      * <p>Compare Quarters (quarter and year).</p>
      *
      * @param value The <code>Calendar</code> value to check.
      * @param compare The <code>Calendar</code> to check the value against.
      * @return Zero if the quarters are equal, -1 if first
      * parameter's quarter is less than the seconds and +1 if the first
      * parameter's quarter is greater than.
      */
     public int compareQuarters(final Calendar value, final Calendar compare) {
         return compareQuarters(value, compare, 1);
     }
 
     /**
      * <p>Compare Quarters (quarter and year).</p>
      *
      * @param value The <code>Calendar</code> value to check.
      * @param compare The <code>Calendar</code> to compare the value to.
      * @param monthOfFirstQuarter The  month that the first quarter starts.
      * @return Zero if the quarters are equal, -1 if first
      * parameter's quarter is less than the seconds and +1 if the first
      * parameter's quarter is greater than.
      */
     @Override
     public int compareQuarters(final Calendar value, final Calendar compare, final int monthOfFirstQuarter) {
         return super.compareQuarters(value, compare, monthOfFirstQuarter);
     }
 
     /**
      * <p>Compare Weeks (week and year).</p>
      *
      * @param value The <code>Calendar</code> value to check.
      * @param compare The <code>Calendar</code> to compare the value to.
      * @return Zero if the weeks are equal, -1 if first
      * parameter's week is less than the seconds and +1 if the first
      * parameter's week is greater than.
      */
     public int compareWeeks(final Calendar value, final Calendar compare) {
         return compare(value, compare, Calendar.WEEK_OF_YEAR);
     }
 
     /**
      * <p>Compare Years.</p>
      *
      * @param value The <code>Calendar</code> value to check.
      * @param compare The <code>Calendar</code> to compare the value to.
      * @return Zero if the years are equal, -1 if first
      * parameter's year is less than the seconds and +1 if the first
      * parameter's year is greater than.
      */
     public int compareYears(final Calendar value, final Calendar compare) {
         return compare(value, compare, Calendar.YEAR);
     }
 
     /**
      * <p>Convert the parsed <code>Date</code> to a <code>Calendar</code>.</p>
      *
      * @param value The parsed <code>Date</code> object created.
      * @param formatter The Format used to parse the value with.
      * @return The parsed value converted to a <code>Calendar</code>.
      */
     @Override
     protected Object processParsedValue(final Object value, final Format formatter) {
         return ((DateFormat) formatter).getCalendar();
     }
 
     /**
      * <p>Validate/convert a <code>Calendar</code> using the default
      *    <code>Locale</code> and <code>TimeZone</code>.
      *
      * @param value The value validation is being performed on.
      * @return The parsed <code>Calendar</code> if valid or {@code null}
      *  if invalid.
      */
     public Calendar validate(final String value) {
         return (Calendar) parse(value, (String) null, (Locale) null, (TimeZone) null);
     }
 
     /**
      * <p>Validate/convert a <code>Calendar</code> using the specified
      *    <code>Locale</code> and default <code>TimeZone</code>.
      *
      * @param value The value validation is being performed on.
      * @param locale The locale to use for the date format, system default if null.
      * @return The parsed <code>Calendar</code> if valid or {@code null} if invalid.
      */
     public Calendar validate(final String value, final Locale locale) {
         return (Calendar) parse(value, (String) null, locale, (TimeZone) null);
     }
 
     /**
      * <p>Validate/convert a <code>Calendar</code> using the specified
      *    <code>Locale</code> and <code>TimeZone</code>.
      *
      * @param value The value validation is being performed on.
      * @param locale The locale to use for the date format, system default if null.
      * @param timeZone The Time Zone used to parse the date, system default if null.
      * @return The parsed <code>Calendar</code> if valid or {@code null} if invalid.
      */
     public Calendar validate(final String value, final Locale locale, final TimeZone timeZone) {
         return (Calendar) parse(value, (String) null, locale, timeZone);
     }
 
     /**
      * <p>Validate/convert a <code>Calendar</code> using the specified
      *    <i>pattern</i> and default <code>TimeZone</code>.
      *
      * @param value The value validation is being performed on.
      * @param pattern The pattern used to validate the value against.
      * @return The parsed <code>Calendar</code> if valid or {@code null} if invalid.
      */
     public Calendar validate(final String value, final String pattern) {
         return (Calendar) parse(value, pattern, (Locale) null, (TimeZone) null);
     }
 
     /**
      * <p>Validate/convert a <code>Calendar</code> using the specified pattern
      *    and <code>Locale</code> and the default <code>TimeZone</code>.
      *
      * @param value The value validation is being performed on.
      * @param pattern The pattern used to validate the value against, or the
      *        default for the <code>Locale</code> if {@code null}.
      * @param locale The locale to use for the date format, system default if null.
      * @return The parsed <code>Calendar</code> if valid or {@code null} if invalid.
      */
     public Calendar validate(final String value, final String pattern, final Locale locale) {
         return (Calendar) parse(value, pattern, locale, (TimeZone) null);
     }
 
     /**
      * <p>Validate/convert a <code>Calendar</code> using the specified
      *    pattern, and <code>Locale</code> and <code>TimeZone</code>.
      *
      * @param value The value validation is being performed on.
      * @param pattern The pattern used to validate the value against, or the
      *        default for the <code>Locale</code> if {@code null}.
      * @param locale The locale to use for the date format, system default if null.
      * @param timeZone The Time Zone used to parse the date, system default if null.
      * @return The parsed <code>Calendar</code> if valid or {@code null} if invalid.
      */
     public Calendar validate(final String value, final String pattern, final Locale locale, final TimeZone timeZone) {
         return (Calendar) parse(value, pattern, locale, timeZone);
     }
 
     /**
      * <p>Validate/convert a <code>Calendar</code> using the specified
      *    <i>pattern</i> and <code>TimeZone</code>.
      *
      * @param value The value validation is being performed on.
      * @param pattern The pattern used to validate the value against.
      * @param timeZone The Time Zone used to parse the date, system default if null.
      * @return The parsed <code>Calendar</code> if valid or {@code null} if invalid.
      */
     public Calendar validate(final String value, final String pattern, final TimeZone timeZone) {
         return (Calendar) parse(value, pattern, (Locale) null, timeZone);
     }
 
     /**
      * <p>Validate/convert a <code>Calendar</code> using the specified
      *    <code>TimeZone</code> and default <code>Locale</code>.
      *
      * @param value The value validation is being performed on.
      * @param timeZone The Time Zone used to parse the date, system default if null.
      * @return The parsed <code>Calendar</code> if valid or {@code null}
      *  if invalid.
      */
     public Calendar validate(final String value, final TimeZone timeZone) {
         return (Calendar) parse(value, (String) null, (Locale) null, timeZone);
     }
 
 }