1 /*
   2  * Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 
  27 package javax.print.attribute;
  28 
  29 import java.io.Serializable;
  30 
  31 import java.util.Date;
  32 
  33 /**
  34  * Class DateTimeSyntax is an abstract base class providing the common
  35  * implementation of all attributes whose value is a date and time.
  36  * <P>
  37  * Under the hood, a date-time attribute is stored as a value of class
  38  * {@code java.util.Date}. You can get a date-time attribute's Date value by
  39  * calling {@link #getValue() getValue()}. A date-time attribute's
  40  * Date value is established when it is constructed (see {@link
  41  * #DateTimeSyntax(Date) DateTimeSyntax(Date)}). Once
  42  * constructed, a date-time attribute's value is immutable.
  43  * <P>
  44  * To construct a date-time attribute from separate values of the year, month,
  45  * day, hour, minute, and so on, use a {@code java.util.Calendar}
  46  * object to construct a {@code java.util.Date} object, then use the
  47  * {@code java.util.Date} object to construct the date-time attribute.
  48  * To convert
  49  * a date-time attribute to separate values of the year, month, day, hour,
  50  * minute, and so on, create a {@code java.util.Calendar} object and
  51  * set it to the {@code java.util.Date} from the date-time attribute. Class
  52  * DateTimeSyntax stores its value in the form of a {@code java.util.Date}
  53  * rather than a {@code java.util.Calendar} because it typically takes
  54  * less memory to store and less time to compare a {@code java.util.Date}
  55  * than a {@code java.util.Calendar}.
  56  *
  57  * @author  Alan Kaminsky
  58  */
  59 public abstract class DateTimeSyntax implements Serializable, Cloneable {
  60 
  61     private static final long serialVersionUID = -1400819079791208582L;
  62 
  63     // Hidden data members.
  64 
  65     /**
  66      * This date-time attribute's {@code java.util.Date} value.
  67      * @serial
  68      */
  69     private Date value;
  70 
  71     // Hidden constructors.
  72 
  73     /**
  74      * Construct a new date-time attribute with the given
  75      * {@code java.util.Date} value.
  76      *
  77      * @param  value   {@code java.util.Date} value.
  78      *
  79      * @exception  NullPointerException
  80      *     (unchecked exception) Thrown if {@code theValue} is null.
  81      */
  82     protected DateTimeSyntax(Date value) {
  83         if (value == null) {
  84             throw new NullPointerException("value is null");
  85         }
  86         this.value = value;
  87     }
  88 
  89     // Exported operations.
  90 
  91     /**
  92      * Returns this date-time attribute's {@code java.util.Date}
  93      * value.
  94      * @return the Date.
  95      */
  96     public Date getValue() {
  97         return new Date (value.getTime());
  98     }
  99 
 100     // Exported operations inherited and overridden from class Object.
 101 
 102     /**
 103      * Returns whether this date-time attribute is equivalent to the passed in
 104      * object. To be equivalent, all of the following conditions must be true:
 105      * <OL TYPE=1>
 106      * <LI>
 107      * {@code object} is not null.
 108      * <LI>
 109      * {@code object} is an instance of class DateTimeSyntax.
 110      * <LI>
 111      * This date-time attribute's {@code java.util.Date} value and
 112      * {@code object}'s {@code java.util.Date} value are
 113      * equal. </OL>
 114      *
 115      * @param  object  Object to compare to.
 116      *
 117      * @return  True if {@code object} is equivalent to this date-time
 118      *          attribute, false otherwise.
 119      */
 120     public boolean equals(Object object) {
 121         return (object != null &&
 122                 object instanceof DateTimeSyntax &&
 123                 value.equals(((DateTimeSyntax) object).value));
 124     }
 125 
 126     /**
 127      * Returns a hash code value for this date-time attribute. The hashcode is
 128      * that of this attribute's {@code java.util.Date} value.
 129      */
 130     public int hashCode() {
 131         return value.hashCode();
 132     }
 133 
 134     /**
 135      * Returns a string value corresponding to this date-time attribute.
 136      * The string value is just this attribute's
 137      * {@code java.util.Date}  value
 138      * converted to a string.
 139      */
 140     public String toString() {
 141         return "" + value;
 142     }
 143 
 144 }