/* TreeUI.java --
Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
This file is part of GNU Classpath.
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permission to link this library with independent modules to produce an
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package javax.swing.plaf;
import java.awt.Rectangle;
import javax.swing.JTree;
import javax.swing.tree.TreePath;
/**
* An abstract base class for delegates that provide the user
* interface for <code>JTree</code>.
*
* @see javax.swing.JTree
*
* @author Sascha Brawer (brawer@dandelis.ch)
*/
public abstract class TreeUI
extends ComponentUI
{
/**
* Constructs a new <code>TreeUI</code>.
*/
public TreeUI()
{
}
/**
* Determines the geometric extent of the label that is
* drawn for a path.
*
* @param tree the <code>JTree</code> for which this delegate
* object provides the user interface.
*
* @param path the path whose label extent is requested.
*
* @return a rectangle enclosing the label, or <code>null</code>
* if <code>path</code> contains invalid nodes.
*/
public abstract Rectangle getPathBounds(JTree tree, TreePath path);
/**
* Creates a <code>TreePath</code> for the specified row.
*
* @param tree the <code>JTree</code> for which this delegate
* object provides the user interface.
*
* @param row the index of the row, which should be a number
* in the range <code>[0, getRowCount(tree) - 1]</code>.
*
* @return a <code>TreePath</code> for the specified row, or
* <code>null</code> if <code>row</code> is outside
* the valid range.
*/
public abstract TreePath getPathForRow(JTree tree, int row);
/**
* Determines in which row a <code>TreePath</code> is currently
* being displayed.
*
* @param tree the <code>JTree</code> for which this delegate
* object provides the user interface.
*
* @param path the path for which the caller wants to know
* in which row it is being displayed.
*
* @return a number in the range <code>[0, getRowCount(tree)
* - 1]</code> if the path is currently on display;
* <code>-1</code> if the path is not shown to the
* user.
*/
public abstract int getRowForPath(JTree tree, TreePath path);
/**
* Counts how many rows are currently displayed.
*
* @param tree the <code>JTree</code> for which this delegate
* object provides the user interface.
*
* @return the number of visible rows.
*/
public abstract int getRowCount(JTree tree);
/**
* Finds the path that is closest to the specified position.
*
* <p><img src="doc-files/TreeUI-1.png" width="300" height="250"
* alt="[A screen shot of a JTree]" />
*
* <p>As shown by the above illustration, the bounds of the
* closest path do not necessarily need to contain the passed
* location.
*
* @param tree the <code>JTree</code> for which this delegate
* object provides the user interface.
*
* @param x the horizontal location, relative to the origin
* of <code>tree</code>.
*
* @param y the vertical location, relative to the origin
* of <code>tree</code>.
*
* @return the closest path, or <code>null</code> if the
* tree is currenlty not displaying any paths at all.
*/
public abstract TreePath getClosestPathForLocation(JTree tree,
int x, int y);
/**
* Determines whether the user is currently editing a tree cell.
*
* @param tree the <code>JTree</code> for which this delegate
* object provides the user interface.
*
* @see #getEditingPath
*/
public abstract boolean isEditing(JTree tree);
/**
* Stops editing a tree cell, committing the entered value into the
* tree’s model. If no editing session is active, or if the
* active editor does not agree to stopping, nothing happens. In
* some look and feels, this action happens when the user has
* pressed the enter key.
*
* @param tree the <code>JTree</code> for which this delegate
* object provides the user interface.
*
* @return <code>false</code> if the editing still goes on because
* the cell editor has objected to stopping the session;
* <code>true</code> if editing has been stopped.
*/
public abstract boolean stopEditing(JTree tree);
/**
* Cancels editing a tree cell, discarding any entered value.
* If no editing session is active, nothing happens. The cell
* editor is not given an opportunity to veto the canceling.
* In some look and feels, this action happens when the user has
* pressed the escape key.
*
* @param tree the <code>JTree</code> for which this delegate
* object provides the user interface.
*/
public abstract void cancelEditing(JTree tree);
/**
* Starts a session to edit a tree cell. If the cell editor
* rejects editing the cell, it will just be selected.
*
* @param tree the <code>JTree</code> for which this delegate
* object provides the user interface.
*
* @param path the cell to edit.
*/
public abstract void startEditingAtPath(JTree tree, TreePath path);
/**
* Retrieves the tree cell that is currently being edited.
*
* @return the currently edited path, or <code>null</code>
* if no editing session is currently active.
*/
public abstract TreePath getEditingPath(JTree tree);
}