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package javax.swing.event;
import java.util.EventObject;
import javax.swing.tree.TreePath;
/**
* Encapsulates information describing changes to a tree model, and
* used to notify tree model listeners of the change.
* For more information and examples see
* <a
href="https://docs.oracle.com/javase/tutorial/uiswing/events/treemodellistener.html">How to Write a Tree Model Listener</a>,
* a section in <em>The Java Tutorial.</em>
* <p>
* <strong>Warning:</strong>
* Serialized objects of this class will not be compatible with
* future Swing releases. The current serialization support is
* appropriate for short term storage or RMI between applications running
* the same version of Swing. As of 1.4, support for long term storage
* of all JavaBeans™
* has been added to the <code>java.beans</code> package.
* Please see {@link java.beans.XMLEncoder}.
*
* @author Rob Davis
* @author Ray Ryan
* @author Scott Violet
*/
@SuppressWarnings("serial") // Same-version serialization only
public class TreeModelEvent extends EventObject {
/** Path to the parent of the nodes that have changed. */
protected TreePath path;
/** Indices identifying the position of where the children were. */
protected int[] childIndices;
/** Children that have been removed. */
protected Object[] children;
/**
* Used to create an event when nodes have been changed, inserted, or
* removed, identifying the path to the parent of the modified items as
* an array of Objects. All of the modified objects are siblings which are
* direct descendents (not grandchildren) of the specified parent.
* The positions at which the inserts, deletes, or changes occurred are
* specified by an array of <code>int</code>. The indexes in that array
* must be in order, from lowest to highest.
* <p>
* For changes, the indexes in the model correspond exactly to the indexes
* of items currently displayed in the UI. As a result, it is not really
* critical if the indexes are not in their exact order. But after multiple
* inserts or deletes, the items currently in the UI no longer correspond
* to the items in the model. It is therefore critical to specify the
* indexes properly for inserts and deletes.
* <p>
* For inserts, the indexes represent the <i>final</i> state of the tree,
* after the inserts have occurred. Since the indexes must be specified in
* order, the most natural processing methodology is to do the inserts
* starting at the lowest index and working towards the highest. Accumulate
* a Vector of <code>Integer</code> objects that specify the
* insert-locations as you go, then convert the Vector to an
* array of <code>int</code> to create the event. When the postition-index
* equals zero, the node is inserted at the beginning of the list. When the
* position index equals the size of the list, the node is "inserted" at
* (appended to) the end of the list.
* <p>
* For deletes, the indexes represent the <i>initial</i> state of the tree,
* before the deletes have occurred. Since the indexes must be specified in
* order, the most natural processing methodology is to use a delete-counter.
* Start by initializing the counter to zero and start work through the
* list from lowest to highest. Every time you do a delete, add the current
* value of the delete-counter to the index-position where the delete occurred,
* and append the result to a Vector of delete-locations, using
* <code>addElement()</code>. Then increment the delete-counter. The index
* positions stored in the Vector therefore reflect the effects of all previous
* deletes, so they represent each object's position in the initial tree.
* (You could also start at the highest index and working back towards the
* lowest, accumulating a Vector of delete-locations as you go using the
* <code>insertElementAt(Integer, 0)</code>.) However you produce the Vector
* of initial-positions, you then need to convert the Vector of <code>Integer</code>
* objects to an array of <code>int</code> to create the event.
* <p>
* <b>Notes:</b><ul style="list-style-type:none">
* <li>Like the <code>insertNodeInto</code> method in the
* <code>DefaultTreeModel</code> class, <code>insertElementAt</code>
* appends to the <code>Vector</code> when the index matches the size
* of the vector. So you can use <code>insertElementAt(Integer, 0)</code>
* even when the vector is empty.</li>
* <li>To create a node changed event for the root node, specify the parent
* and the child indices as <code>null</code>.</li>
* </ul>
*
* @param source the Object responsible for generating the event (typically
* the creator of the event object passes <code>this</code>
* for its value)
* @param path an array of Object identifying the path to the
* parent of the modified item(s), where the first element
* of the array is the Object stored at the root node and
* the last element is the Object stored at the parent node
* @param childIndices an array of <code>int</code> that specifies the
* index values of the removed items. The indices must be
* in sorted order, from lowest to highest
* @param children an array of Object containing the inserted, removed, or
* changed objects
* @see TreePath
*/
public TreeModelEvent(Object source, Object[] path, int[] childIndices,
Object[] children)
{
this(source, (path == null) ? null : new TreePath(path), childIndices, children);
}
/**
* Used to create an event when nodes have been changed, inserted, or
* removed, identifying the path to the parent of the modified items as
* a TreePath object. For more information on how to specify the indexes
* and objects, see
* <code>TreeModelEvent(Object,Object[],int[],Object[])</code>.
*
* @param source the Object responsible for generating the event (typically
* the creator of the event object passes <code>this</code>
* for its value)
* @param path a TreePath object that identifies the path to the
* parent of the modified item(s)
* @param childIndices an array of <code>int</code> that specifies the
* index values of the modified items
* @param children an array of Object containing the inserted, removed, or
* changed objects
*
* @see #TreeModelEvent(Object,Object[],int[],Object[])
*/
public TreeModelEvent(Object source, TreePath path, int[] childIndices,
Object[] children)
{
super(source);
this.path = path;
this.childIndices = childIndices;
this.children = children;
}
/**
* Used to create an event when the node structure has changed in some way,
* identifying the path to the root of a modified subtree as an array of
* Objects. A structure change event might involve nodes swapping position,
* for example, or it might encapsulate multiple inserts and deletes in the
* subtree stemming from the node, where the changes may have taken place at
* different levels of the subtree.
* <blockquote>
* <b>Note:</b><br>
* JTree collapses all nodes under the specified node, so that only its
* immediate children are visible.
* </blockquote>
*
* @param source the Object responsible for generating the event (typically
* the creator of the event object passes <code>this</code>
* for its value)
* @param path an array of Object identifying the path to the root of the
* modified subtree, where the first element of the array is
* the object stored at the root node and the last element
* is the object stored at the changed node
* @see TreePath
*/
public TreeModelEvent(Object source, Object[] path)
{
this(source, (path == null) ? null : new TreePath(path));
}
/**
* Used to create an event when the node structure has changed in some way,
* identifying the path to the root of the modified subtree as a TreePath
* object. For more information on this event specification, see
* <code>TreeModelEvent(Object,Object[])</code>.
*
* @param source the Object responsible for generating the event (typically
* the creator of the event object passes <code>this</code>
* for its value)
* @param path a TreePath object that identifies the path to the
* change. In the DefaultTreeModel,
* this object contains an array of user-data objects,
* but a subclass of TreePath could use some totally
* different mechanism -- for example, a node ID number
*
* @see #TreeModelEvent(Object,Object[])
*/
public TreeModelEvent(Object source, TreePath path)
{
super(source);
this.path = path;
this.childIndices = new int[0];
}
/**
* For all events, except treeStructureChanged,
* returns the parent of the changed nodes.
* For treeStructureChanged events, returns the ancestor of the
* structure that has changed. This and
* <code>getChildIndices</code> are used to get a list of the effected
* nodes.
* <p>
* The one exception to this is a treeNodesChanged event that is to
* identify the root, in which case this will return the root
* and <code>getChildIndices</code> will return null.
*
* @return the TreePath used in identifying the changed nodes.
* @see TreePath#getLastPathComponent
*/
public TreePath getTreePath() { return path; }
/**
* Convenience method to get the array of objects from the TreePath
* instance that this event wraps.
*
* @return an array of Objects, where the first Object is the one
* stored at the root and the last object is the one
* stored at the node identified by the path
*/
public Object[] getPath() {
if(path != null)
return path.getPath();
return null;
}
/**
* Returns the objects that are children of the node identified by
* <code>getPath</code> at the locations specified by
* <code>getChildIndices</code>. If this is a removal event the
* returned objects are no longer children of the parent node.
*
* @return an array of Object containing the children specified by
* the event
* @see #getPath
* @see #getChildIndices
*/
public Object[] getChildren() {
if(children != null) {
int cCount = children.length;
Object[] retChildren = new Object[cCount];
System.arraycopy(children, 0, retChildren, 0, cCount);
return retChildren;
}
return null;
}
/**
* Returns the values of the child indexes. If this is a removal event
* the indexes point to locations in the initial list where items
* were removed. If it is an insert, the indices point to locations
* in the final list where the items were added. For node changes,
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