gcc/libjava/classpath/javax/swing/SpinnerDateModel.java

/* SpinnerDateModel.java --
   Copyright (C) 2002, 2004, 2006 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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General Public License for more details.

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02110-1301 USA.

Linking this library statically or dynamically with other modules is
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
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package javax.swing;

import java.io.Serializable;
import java.util.Calendar;
import java.util.Date;

import javax.swing.event.ChangeEvent;

/**
 * A date model used by the {@link JSpinner} component.  This implements a 
 * spinner model for dates, rotating a calendar field such as  month, year, 
 * day, week, hour, minute.
 *
 * @author Sven de Marothy
 * @since 1.4
 */
public class SpinnerDateModel extends AbstractSpinnerModel
  implements Serializable
{
  /** The current date. */
  private Calendar date;
  
  /** 
   * A constraint on the start or earliest permitted date (<code>null</code> 
   * for no minimum). 
   */
  private Comparable start;

  /** 
   * A constraint on the end or latest permitted date (<code>null</code> for no 
   * maximum). 
   */
  private Comparable end;
  
  /**
   * The calendar field used to calculate the previous or next date. 
   */
  private int calendarField;

  /**
   * For compatability with Sun's JDK
   */
  private static final long serialVersionUID = -4802518107105940612L;

  /**
   * Constructs a <code>SpinnerDateModel</code> using the current date,
   * no start or end limit, and {@link Calendar#DAY_OF_MONTH} as the calendar 
   * field.
   */
  public SpinnerDateModel()
  {
    this(new Date(), null, null, Calendar.DAY_OF_MONTH);
  }

  /**
   * Constructs a <code>SpinnerDateModel</code> with the specified value, lower
   * and upper bounds, and which spins the specified calendar field. 
   * <p>
   * The <code>start</code> and <code>end</code> limits must have a
   * <code>compareTo</code> method that supports instances of {@link Date}, but
   * do not themselves need to be instances of {@link Date} (although typically
   * they are).
   * 
   * @param value  the initial value/date (<code>null</code> not permitted).
   * @param start  a constraint that specifies the earliest permitted date 
   *     value, or <code>null</code> for no lower limit.
   * @param end  a constraint that specifies the latest permitted date value,
   *     or <code>null</code> for no upper limit.
   * @param calendarField  the <code>Calendar</code> field to spin,
   *     (Calendar.ZONE_OFFSET and Calendar.DST_OFFSET are invalid)
   */
  public SpinnerDateModel(Date value, Comparable start, Comparable end,
                          int calendarField)
  {
    if (value == null) 
      throw new IllegalArgumentException("Null 'value' argument.");
    if (start != null && start.compareTo(value) > 0)
      throw new IllegalArgumentException("Require value on or after start.");
    if (end != null && end.compareTo(value) < 0)
      throw new IllegalArgumentException("Require value on or before end.");
    date = Calendar.getInstance();
    date.setTime(value);
    this.start = start;
    this.end = end;
    setCalendarField(calendarField);
  }

  /**
   * Returns the {@link Calendar} field used to calculate the previous and 
   * next dates in the sequence.
   * 
   * @return The date field code.
   */
  public int getCalendarField()
  {
    return calendarField;
  }

  /**
   * Returns the current date/time.
   * 
   * @return The current date/time (never <code>null</code>).
   * 
   * @see #getValue()
   */
  public Date getDate()
  {
    return date.getTime();
  }

  /**
   * Returns the lower limit on the date/time value, or <code>null</code> if 
   * there is no minimum date/time.
   * 
   * @return The lower limit.
   * 
   * @see #setStart(Comparable)
   */
  public Comparable getStart()
  {
    return start;
  }

  /**
   * Returns the upper limit on the date/time value, or <code>null</code> if 
   * there is no maximum date/time.
   * 
   * @return The upper limit.
   * 
   * @see #setEnd(Comparable)
   */
  public Comparable getEnd()
  {
    return end;
  }

  /**
   * Returns the current date in the sequence (this method returns the same as 
   * {@link #getDate()}).
   * 
   * @return The current date (never <code>null</code>).
   */
  public Object getValue()
  {
    return date.getTime();
  }

  /**
   * Returns the next date in the sequence, or <code>null</code> if the
   * next date is past the upper limit (if one is specified).  The current date 
   * is not changed.
   * 
   * @return The next date, or <code>null</code> if the current value is
   *         the latest date represented by the model.
   *         
   * @see #getEnd()
   */
  public Object getNextValue()
  {
    Calendar nextCal = Calendar.getInstance();
    nextCal.setTime(date.getTime());
    nextCal.roll(calendarField, true);
    Date nextDate = nextCal.getTime();
    if (end != null)
      if (end.compareTo(nextDate) < 0)
        return null;
    return nextDate;
  }

  /**
   * Returns the previous date in the sequence, or <code>null</code> if the
   * previous date is prior to the lower limit (if one is specified).  The 
   * current date is not changed.
   * 
   * @return The previous date, or <code>null</code> if the current value is
   *         the earliest date represented by the model.
   *         
   * @see #getStart()
   */
  public Object getPreviousValue()
  {
    Calendar prevCal = Calendar.getInstance();
    prevCal.setTime(date.getTime());
    prevCal.roll(calendarField, false);
    Date prevDate = prevCal.getTime();
    if (start != null)
      if (start.compareTo(prevDate) > 0)
        return null;
    return prevDate;
  }

  /**
   * Sets the date field to change when calculating the next and previous 
   * values. It must be a valid {@link Calendar} field, excluding 
   * {@link Calendar#ZONE_OFFSET} and {@link Calendar#DST_OFFSET}.
   * 
   * @param calendarField  the calendar field to set.
   * 
   * @throws IllegalArgumentException if <code>calendarField</code> is not 
   *         a valid code.
   */
  public void setCalendarField(int calendarField)
  {
    if (calendarField < 0 || calendarField >= Calendar.FIELD_COUNT
        || calendarField == Calendar.ZONE_OFFSET
        || calendarField == Calendar.DST_OFFSET)
      throw new IllegalArgumentException("Illegal calendarField");

    if (this.calendarField != calendarField)
      {
        this.calendarField = calendarField;
        fireStateChanged();
      }
  }

  /**
   * Sets the lower limit for the date/time value and, if the new limit is 
   * different to the old limit, sends a {@link ChangeEvent} to all registered 
   * listeners.  A <code>null</code> value is interpreted as "no lower limit".  
   * No check is made to ensure that the current date/time is on or after the 
   * new lower limit - the caller is responsible for ensuring that this 
   * relationship holds.  In addition, the caller should ensure that
   * <code>start</code> is {@link Serializable}.
   * 
   * @param start  the new lower limit for the date/time value 
   *     (<code>null</code> permitted).
   */
  public void setStart(Comparable start)
  {
    if (this.start != start)
      {
        this.start = start;
        fireStateChanged();
      }
  }

  /**
   * Sets the upper limit for the date/time value and, if the new limit is 
   * different to the old limit, sends a {@link ChangeEvent} to all registered 
   * listeners.  A <code>null</code> value is interpreted as "no upper limit".  
   * No check is made to ensure that the current date/time is on or before the 
   * new upper limit - the caller is responsible for ensuring that this 
   * relationship holds.  In addition, the caller should ensure that
   * <code>end</code> is {@link Serializable}.
   * 
   * @param end  the new upper limit for the date/time value (<code>null</code>
   *     permitted).
   */
  public void setEnd(Comparable end)
  {
    if (this.end != end)
      {
        this.end = end;
        fireStateChanged();
      }
  }

  /**
   * Sets the current date and, if the new value is different to the old
   * value, sends a {@link ChangeEvent} to all registered listeners.
   *
   * @param value  the new date (<code>null</code> not permitted, must be an 
   *               instance of <code>Date</code>).
   *               
   * @throws IllegalArgumentException if <code>value</code> is not an instance 
   *         of <code>Date</code>.
   */
  public void setValue(Object value)
  {
    if (! (value instanceof Date) || value == null)
      throw new IllegalArgumentException("Value not a date.");
    
    if (!date.getTime().equals(value)) 
      {
        date.setTime((Date) value);
        fireStateChanged();
      }
  }
}