322 lines
8.9 KiB
Java
322 lines
8.9 KiB
Java
|
/* AWTUtilities.java -- Common utility methods for AWT and Swing.
|
||
|
|
Copyright (C) 2005 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
|
||
|
|
the Free Software Foundation; either version 2, or (at your option)
|
||
|
|
any later version.
|
||
|
|
|
||
|
|
GNU Classpath is distributed in the hope that it will be useful, but
|
||
|
|
WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||
|
|
General Public License for more details.
|
||
|
|
|
||
|
|
You should have received a copy of the GNU General Public License
|
||
|
|
along with GNU Classpath; see the file COPYING. If not, write to the
|
||
|
|
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
|
||
|
|
02110-1301 USA.
|
||
|
|
|
||
|
|
Linking this library statically or dynamically with other modules is
|
||
|
|
making a combined work based on this library. Thus, the terms and
|
||
|
|
conditions of the GNU General Public License cover the whole
|
||
|
|
combination.
|
||
|
|
|
||
|
|
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
|
||
|
|
modules, and to copy and distribute the resulting executable under
|
||
|
|
terms of your choice, provided that you also meet, for each linked
|
||
|
|
independent module, the terms and conditions of the license of that
|
||
|
|
module. An independent module is a module which is not derived from
|
||
|
|
or based on this library. If you modify this library, you may extend
|
||
|
|
this exception to your version of the library, but you are not
|
||
|
|
obligated to do so. If you do not wish to do so, delete this
|
||
|
|
exception statement from your version. */
|
||
|
|
|
||
|
|
package gnu.java.awt;
|
||
|
|
|
||
|
|
import java.awt.Component;
|
||
|
|
import java.awt.Container;
|
||
|
|
import java.util.AbstractSequentialList;
|
||
|
|
import java.util.List;
|
||
|
|
import java.util.ListIterator;
|
||
|
|
import java.util.NoSuchElementException;
|
||
|
|
import java.util.WeakHashMap;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* This class provides utility methods that are commonly used in AWT
|
||
|
|
* (and Swing).
|
||
|
|
*/
|
||
|
|
public class AWTUtilities
|
||
|
|
{
|
||
|
|
|
||
|
|
/**
|
||
|
|
* This List implementation wraps the Component[] returned by
|
||
|
|
* {@link Container#getComponents()} and iterates over the visible Components
|
||
|
|
* in that array. This class is used in {@link #getVisibleChildren}.
|
||
|
|
*/
|
||
|
|
static class VisibleComponentList extends AbstractSequentialList
|
||
|
|
{
|
||
|
|
/**
|
||
|
|
* The ListIterator for this List.
|
||
|
|
*/
|
||
|
|
class VisibleComponentIterator implements ListIterator
|
||
|
|
{
|
||
|
|
/** The current index in the Component[]. */
|
||
|
|
int index;
|
||
|
|
|
||
|
|
/** The index in the List of visible Components. */
|
||
|
|
int listIndex;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Creates a new VisibleComponentIterator that starts at the specified
|
||
|
|
* <code>listIndex</code>. The array of Components is searched from
|
||
|
|
* the beginning to find the matching array index.
|
||
|
|
*
|
||
|
|
* @param listIndex the index from where to begin iterating
|
||
|
|
*/
|
||
|
|
VisibleComponentIterator(int listIndex)
|
||
|
|
{
|
||
|
|
this.listIndex = listIndex;
|
||
|
|
int visibleComponentsFound = 0;
|
||
|
|
for (index = 0; visibleComponentsFound != listIndex; index++)
|
||
|
|
{
|
||
|
|
if (components[index].isVisible())
|
||
|
|
visibleComponentsFound++;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns <code>true</code> if there are more visible components in the
|
||
|
|
* array, <code>false</code> otherwise.
|
||
|
|
*
|
||
|
|
* @return <code>true</code> if there are more visible components in the
|
||
|
|
* array, <code>false</code> otherwise
|
||
|
|
*/
|
||
|
|
public boolean hasNext()
|
||
|
|
{
|
||
|
|
boolean hasNext = false;
|
||
|
|
for (int i = index; i < components.length; i++)
|
||
|
|
{
|
||
|
|
if (components[i].isVisible())
|
||
|
|
{
|
||
|
|
hasNext = true;
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return hasNext;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns the next visible <code>Component</code> in the List.
|
||
|
|
*
|
||
|
|
* @return the next visible <code>Component</code> in the List
|
||
|
|
*
|
||
|
|
* @throws if there is no next element
|
||
|
|
*/
|
||
|
|
public Object next()
|
||
|
|
{
|
||
|
|
Object o = null;
|
||
|
|
for (; index < components.length; index++)
|
||
|
|
{
|
||
|
|
if (components[index].isVisible())
|
||
|
|
{
|
||
|
|
o = components[index];
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if (o != null)
|
||
|
|
{
|
||
|
|
index++;
|
||
|
|
listIndex++;
|
||
|
|
return o;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
throw new NoSuchElementException();
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns <code>true</code> if there are more visible components in the
|
||
|
|
* array in the reverse direction, <code>false</code> otherwise.
|
||
|
|
*
|
||
|
|
* @return <code>true</code> if there are more visible components in the
|
||
|
|
* array in the reverse direction, <code>false</code> otherwise
|
||
|
|
*/
|
||
|
|
public boolean hasPrevious()
|
||
|
|
{
|
||
|
|
boolean hasPrevious = false;
|
||
|
|
for (int i = index - 1; i >= 0; i--)
|
||
|
|
{
|
||
|
|
if (components[i].isVisible())
|
||
|
|
{
|
||
|
|
hasPrevious = true;
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return hasPrevious;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns the previous visible <code>Component</code> in the List.
|
||
|
|
*
|
||
|
|
* @return the previous visible <code>Component</code> in the List
|
||
|
|
*
|
||
|
|
* @throws NoSuchElementException if there is no previous element
|
||
|
|
*/
|
||
|
|
public Object previous()
|
||
|
|
{
|
||
|
|
Object o = null;
|
||
|
|
for (index--; index >= 0; index--)
|
||
|
|
{
|
||
|
|
if (components[index].isVisible())
|
||
|
|
{
|
||
|
|
o = components[index];
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if (o != null)
|
||
|
|
{
|
||
|
|
listIndex--;
|
||
|
|
return o;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
throw new NoSuchElementException();
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns the index of the next element in the List.
|
||
|
|
*
|
||
|
|
* @return the index of the next element in the List
|
||
|
|
*/
|
||
|
|
public int nextIndex()
|
||
|
|
{
|
||
|
|
return listIndex + 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns the index of the previous element in the List.
|
||
|
|
*
|
||
|
|
* @return the index of the previous element in the List
|
||
|
|
*/
|
||
|
|
public int previousIndex()
|
||
|
|
{
|
||
|
|
return listIndex - 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* This operation is not supported because the List is immutable.
|
||
|
|
*
|
||
|
|
* @throws UnsupportedOperationException because the List is immutable
|
||
|
|
*/
|
||
|
|
public void remove()
|
||
|
|
{
|
||
|
|
throw new UnsupportedOperationException
|
||
|
|
("VisibleComponentList is immutable");
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* This operation is not supported because the List is immutable.
|
||
|
|
*
|
||
|
|
* @param o not used here
|
||
|
|
*
|
||
|
|
* @throws UnsupportedOperationException because the List is immutable
|
||
|
|
*/
|
||
|
|
public void set(Object o)
|
||
|
|
{
|
||
|
|
throw new UnsupportedOperationException
|
||
|
|
("VisibleComponentList is immutable");
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* This operation is not supported because the List is immutable.
|
||
|
|
*
|
||
|
|
* @param o not used here
|
||
|
|
*
|
||
|
|
* @throws UnsupportedOperationException because the List is immutable
|
||
|
|
*/
|
||
|
|
public void add(Object o)
|
||
|
|
{
|
||
|
|
throw new UnsupportedOperationException
|
||
|
|
("VisibleComponentList is immutable");
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* The components over which we iterate. Only the visible components
|
||
|
|
* are returned by this List.
|
||
|
|
*/
|
||
|
|
Component[] components;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Creates a new instance of VisibleComponentList that wraps the specified
|
||
|
|
* <code>Component[]</code>.
|
||
|
|
*
|
||
|
|
* @param c the <code>Component[]</code> to be wrapped.
|
||
|
|
*/
|
||
|
|
VisibleComponentList(Component[] c)
|
||
|
|
{
|
||
|
|
components = c;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns a {@link ListIterator} for iterating over this List.
|
||
|
|
*
|
||
|
|
* @return a {@link ListIterator} for iterating over this List
|
||
|
|
*/
|
||
|
|
public ListIterator listIterator(int index)
|
||
|
|
{
|
||
|
|
return new VisibleComponentIterator(index);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns the number of visible components in the wrapped Component[].
|
||
|
|
*
|
||
|
|
* @return the number of visible components
|
||
|
|
*/
|
||
|
|
public int size()
|
||
|
|
{
|
||
|
|
int visibleComponents = 0;
|
||
|
|
for (int i = 0; i < components.length; i++)
|
||
|
|
if (components[i].isVisible())
|
||
|
|
visibleComponents++;
|
||
|
|
return visibleComponents;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* The cache for our List instances. We try to hold one instance of
|
||
|
|
* VisibleComponentList for each Component[] that is requested. Note
|
||
|
|
* that we use a WeakHashMap for caching, so that the cache itself
|
||
|
|
* does not keep the array or the List from beeing garbage collected
|
||
|
|
* if no other objects hold references to it.
|
||
|
|
*/
|
||
|
|
static WeakHashMap visibleChildrenCache = new WeakHashMap();
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns the visible children of a {@link Container}. This method is
|
||
|
|
* commonly needed in LayoutManagers, because they only have to layout
|
||
|
|
* the visible children of a Container.
|
||
|
|
*
|
||
|
|
* @param c the Container from which to extract the visible children
|
||
|
|
*
|
||
|
|
* @return the visible children of <code>c</code>
|
||
|
|
*/
|
||
|
|
public static List getVisibleChildren(Container c)
|
||
|
|
{
|
||
|
|
Component[] children = c.getComponents();
|
||
|
|
Object o = visibleChildrenCache.get(children);
|
||
|
|
VisibleComponentList visibleChildren = null;
|
||
|
|
if (o == null)
|
||
|
|
{
|
||
|
|
visibleChildren = new VisibleComponentList(children);
|
||
|
|
visibleChildrenCache.put(children, visibleChildren);
|
||
|
|
}
|
||
|
|
else
|
||
|
|
visibleChildren = (VisibleComponentList) o;
|
||
|
|
|
||
|
|
return visibleChildren;
|
||
|
|
}
|
||
|
|
}
|