/*
 * @(#)ListSelectionModel.java	1.23 06/07/11
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package javax.swing;

import javax.swing.event.*;

/**
 * This interface represents the current state of the 
 * selection for any of the components that display a 
 * list of values with stable indices.  The selection is 
 * modeled as a set of intervals, each interval represents
 * a contiguous range of selected list elements.
 * The methods for modifying the set of selected intervals
 * all take a pair of indices, index0 and index1, that represent
 * a closed interval, i.e. the interval includes both index0 and
 * index1.
 * 
 * @version 1.23 07/11/06
 * @author Hans Muller
 * @author Philip Milne
 * @see DefaultListSelectionModel
 */

public interface ListSelectionModel {
    /**
     * A value for the selectionMode property: select one list index
     * at a time.
     * 
     * @see #setSelectionMode
     */
    int SINGLE_SELECTION = 0;

    /**
     * A value for the selectionMode property: select one contiguous
     * range of indices at a time.
     * 
     * @see #setSelectionMode
     */
    int SINGLE_INTERVAL_SELECTION = 1;

    /**
     * A value for the selectionMode property: select one or more 
     * contiguous ranges of indices at a time.
     * 
     * @see #setSelectionMode
     */
    int MULTIPLE_INTERVAL_SELECTION = 2;


    /** 
     * Changes the selection to be between {@code index0} and {@code index1}
     * inclusive. {@code index0} doesn't have to be less than or equal to
     * {@code index1}.
     * <p>
     * In {@code SINGLE_SELECTION} selection mode, only the second index
     * is used.
     * <p>
     * If this represents a change to the current selection, then each
     * {@code ListSelectionListener} is notified of the change.
     * 
     * @param index0 one end of the interval.
     * @param index1 other end of the interval
     * @see #addListSelectionListener
     */
    void setSelectionInterval(int index0, int index1);


    /** 
     * Changes the selection to be the set union of the current selection
     * and the indices between {@code index0} and {@code index1} inclusive.
     * {@code index0} doesn't have to be less than or equal to {@code index1}.
     * <p>
     * In {@code SINGLE_SELECTION} selection mode, this is equivalent
     * to calling {@code setSelectionInterval}, and only the second index
     * is used. In {@code SINGLE_INTERVAL_SELECTION} selection mode, this
     * method behaves like {@code setSelectionInterval}, unless the given
     * interval is immediately adjacent to or overlaps the existing selection,
     * and can therefore be used to grow the selection.
     * <p>
     * If this represents a change to the current selection, then each
     * {@code ListSelectionListener} is notified of the change.
     * 
     * @param index0 one end of the interval.
     * @param index1 other end of the interval
     * @see #addListSelectionListener
     * @see #setSelectionInterval
     */
    void addSelectionInterval(int index0, int index1);


    /** 
     * Changes the selection to be the set difference of the current selection
     * and the indices between {@code index0} and {@code index1} inclusive.
     * {@code index0} doesn't have to be less than or equal to {@code index1}.
     * <p>
     * In {@code SINGLE_INTERVAL_SELECTION} selection mode, if the removal
     * would produce two disjoint selections, the removal is extended through
     * the greater end of the selection. For example, if the selection is
     * {@code 0-10} and you supply indices {@code 5,6} (in any order) the
     * resulting selection is {@code 0-4}.
     * <p>
     * If this represents a change to the current selection, then each
     * {@code ListSelectionListener} is notified of the change.
     * 
     * @param index0 one end of the interval.
     * @param index1 other end of the interval
     * @see #addListSelectionListener
     */
    void removeSelectionInterval(int index0, int index1);


    /**
     * Returns the first selected index or -1 if the selection is empty.
     */
    int getMinSelectionIndex();


    /**
     * Returns the last selected index or -1 if the selection is empty.
     */
    int getMaxSelectionIndex();


    /** 
     * Returns true if the specified index is selected.
     */
    boolean isSelectedIndex(int index);

    
    /**
     * Return the first index argument from the most recent call to 
     * setSelectionInterval(), addSelectionInterval() or removeSelectionInterval().
     * The most recent index0 is considered the "anchor" and the most recent
     * index1 is considered the "lead".  Some interfaces display these
     * indices specially, e.g. Windows95 displays the lead index with a 
     * dotted yellow outline.
     * 
     * @see #getLeadSelectionIndex
     * @see #setSelectionInterval
     * @see #addSelectionInterval
     */
    int getAnchorSelectionIndex();


    /**
     * Set the anchor selection index. 
     * 
     * @see #getAnchorSelectionIndex
     */
    void setAnchorSelectionIndex(int index);


    /**
     * Return the second index argument from the most recent call to 
     * setSelectionInterval(), addSelectionInterval() or removeSelectionInterval().
     * 
     * @see #getAnchorSelectionIndex
     * @see #setSelectionInterval
     * @see #addSelectionInterval
     */
    int getLeadSelectionIndex();

    /**
     * Set the lead selection index. 
     * 
     * @see #getLeadSelectionIndex
     */
    void setLeadSelectionIndex(int index);

    /**
     * Change the selection to the empty set.  If this represents
     * a change to the current selection then notify each ListSelectionListener.
     * 
     * @see #addListSelectionListener
     */
    void clearSelection();

    /**
     * Returns true if no indices are selected.
     */
    boolean isSelectionEmpty();
    
    /** 
     * Insert length indices beginning before/after index.  This is typically 
     * called to sync the selection model with a corresponding change
     * in the data model.
     */
    void insertIndexInterval(int index, int length, boolean before);

    /** 
     * Remove the indices in the interval index0,index1 (inclusive) from
     * the selection model.  This is typically called to sync the selection
     * model width a corresponding change in the data model.
     */
    void removeIndexInterval(int index0, int index1);

    /**
     * Sets the {@code valueIsAdjusting} property, which indicates whether
     * or not upcoming selection changes should be considered part of a single
     * change. The value of this property is used to initialize the
     * {@code valueIsAdjusting} property of the {@code ListSelectionEvent}s that
     * are generated.
     * <p>
     * For example, if the selection is being updated in response to a user
     * drag, this property can be set to {@code true} when the drag is initiated
     * and set to {@code false} when the drag is finished. During the drag,
     * listeners receive events with a {@code valueIsAdjusting} property
     * set to {@code true}. At the end of the drag, when the change is
     * finalized, listeners receive an event with the value set to {@code false}.
     * Listeners can use this pattern if they wish to update only when a change
     * has been finalized.
     * <p>
     * Setting this property to {@code true} begins a series of changes that
     * is to be considered part of a single change. When the property is changed
     * back to {@code false}, an event is sent out characterizing the entire
     * selection change (if there was one), with the event's
     * {@code valueIsAdjusting} property set to {@code false}.
     * 
     * @param valueIsAdjusting the new value of the property
     * @see #getValueIsAdjusting
     * @see javax.swing.event.ListSelectionEvent#getValueIsAdjusting
     */
    void setValueIsAdjusting(boolean valueIsAdjusting);

    /**
     * Returns {@code true} if the selection is undergoing a series of changes.
     *
     * @return true if the selection is undergoing a series of changes
     * @see #setValueIsAdjusting
     */
    boolean getValueIsAdjusting();

    /**
     * Sets the selection mode. The following list describes the accepted
     * selection modes:
     * <ul>
     * <li>{@code ListSelectionModel.SINGLE_SELECTION} -
     *   Only one list index can be selected at a time. In this mode,
     *   {@code setSelectionInterval} and {@code addSelectionInterval} are
     *   equivalent, both replacing the current selection with the index
     *   represented by the second argument (the "lead").
     * <li>{@code ListSelectionModel.SINGLE_INTERVAL_SELECTION} -
     *   Only one contiguous interval can be selected at a time.
     *   In this mode, {@code addSelectionInterval} behaves like
     *   {@code setSelectionInterval} (replacing the current selection),
     *   unless the given interval is immediately adjacent to or overlaps
     *   the existing selection, and can therefore be used to grow it.
     * <li>{@code ListSelectionModel.MULTIPLE_INTERVAL_SELECTION} -
     *   In this mode, there's no restriction on what can be selected.
     * </ul>
     * 
     * @see #getSelectionMode
     * @throws IllegalArgumentException if the selection mode isn't
     *         one of those allowed
     */
    void setSelectionMode(int selectionMode);

    /**
     * Returns the current selection mode.
     *
     * @return the current selection mode
     * @see #setSelectionMode
     */
    int getSelectionMode();

    /**
     * Add a listener to the list that's notified each time a change
     * to the selection occurs.
     * 
     * @param x the ListSelectionListener
     * @see #removeListSelectionListener
     * @see #setSelectionInterval
     * @see #addSelectionInterval
     * @see #removeSelectionInterval
     * @see #clearSelection
     * @see #insertIndexInterval
     * @see #removeIndexInterval
     */  
    void addListSelectionListener(ListSelectionListener x);

    /**
     * Remove a listener from the list that's notified each time a 
     * change to the selection occurs.
     * 
     * @param x the ListSelectionListener
     * @see #addListSelectionListener
     */  
    void removeListSelectionListener(ListSelectionListener x);
}