/* SpinnerModel.java -- 
   Copyright (C) 2003, 2004  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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any later version.

GNU Classpath is distributed in the hope that it will be useful, but
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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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
executable, regardless of the license terms of these independent
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terms of your choice, provided that you also meet, for each linked
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this exception to your version of the library, but you are not
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package javax.swing;

import javax.swing.event.ChangeListener;

/**
 * @since 1.4
 */
public interface SpinnerModel
{
  /**
   * Sets the current value of the model to that specified.
   * Implementations can choose to refuse to accept the value
   * and throw an exception instead.  For example, a date model
   * may throw invalid dates, or a list model may throw out
   * values which don't exist in the underlying list.  Models
   * may also throw out unusual values, such as null.  The decision
   * is left to the discretion of the implementator.  If the
   * operation succeeds, the implementation should also notify
   * any registered <code>ChangeListener</code>s.
   *
   * @param value The new value of the model.
   * @throws IllegalArgumentException if the model does not accept
   *         the given value.
   */
  void setValue(Object value);

  /**
   * Returns the current value of the model.
   *
   * @return The current value.
   */
  Object getValue();

  /**
   * Returns the next value from the model.  If the model is bounded,
   * this method may return null when the upper bound is met.
   * The current value is not changed.
   *
   * @return The next value, or null if there are no more values
   *         to retrieve.
   */
  Object getNextValue();

  /**
   * Returns the previous value from the model.  If the model is
   * bounded, this method may return null when the lower bound is
   * met.  The current value is not changed.
   *
   * @return The previous value, or null if there are no more
   *         values to retrieve.
   */
  Object getPreviousValue();

  /**
   * Adds a <code>ChangeListener</code> to the list of registered
   * listeners.  Each listener is notified when the current value
   * is changed.
   *
   * @param listener The new listener to register.
   */
  void addChangeListener(ChangeListener listener);

  /**
   * Removes a given <code>ChangeListener</code> from the list
   * of registered listeners.
   *
   * @param listener The listener to remove.
   */
  void removeChangeListener(ChangeListener listener);
    
}