| /******************************************************************************* |
| * Copyright (c) 2005 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.jface.databinding; |
| |
| import java.util.EventObject; |
| |
| /** |
| * An event describing a change to an updatable object. |
| * <p> |
| * <code>ChangeEvent</code> objects are delivered to |
| * <code>IChangeEventListener</code> objects registered with an |
| * <code>IUpdatable</code> object when a change occurs in the updatable. |
| * </p> |
| * |
| * <p> |
| * <strong>EXPERIMENTAL</strong>. This class or interface has been added as |
| * part of a work in progress. There is no guarantee that this API will remain |
| * unchanged during the 3.2 release cycle. Please do not use this API without |
| * consulting with the Platform/UI team. |
| * </p> |
| * |
| * @since 3.2 |
| */ |
| public class ChangeEvent extends EventObject { |
| |
| |
| /** |
| * Position constant denoting a change affecting more than one element, or a |
| * change with an unknown position. |
| */ |
| public static final int POSITION_UNKNOWN = -1; |
| |
| /** |
| * Change type constant denoting a general change. If the source is a |
| * list, getPosition() returns the index of the changed element, or |
| * <code>POSITION_UNKNOWN</code> if more than one element was changed, |
| * added or removed, or if the position of the changed, added or removed |
| * element is not known. |
| */ |
| public static final int CHANGE = 1; |
| |
| /** |
| * Change type constant denoting an addition of an element to a list. The |
| * added element will be returned by getNewValue(), and the position of the |
| * added element will be returned by getPosition(). |
| */ |
| public static final int ADD = 2; |
| |
| /** |
| * Change type constant denoting a removal of an element from a list. The |
| * removed element will be returned by getOldValue(), and the position of |
| * the removed element before the removal will be returned by getPosition(). |
| */ |
| public static final int REMOVE = 3; |
| |
| /** |
| * Change type constant used to inform listeners about a pending change that |
| * can still be vetoed. The updatable's value has not been changed yet, |
| * <code>getNewValue()</code> returns the new value that will be the |
| * updatable's new value if the change is not vetoed by calling |
| * <code>setVeto(true)</code>. |
| * TODO turn this into flags, so that we can |
| * express pre-add etc. |
| */ |
| public static final int VERIFY = 4; |
| |
| /** |
| * Change type constant denoting a complete replacement of a list. The |
| * added list will be returned by getNewValue(), and the position of the |
| * added element will be returned by getPosition(). |
| */ |
| public static final int REPLACE = 5; |
| |
| /** |
| * Change type constant that is used to inform a listener that a virtual data is being |
| * requested. |
| */ |
| public static final int VIRTUAL = 6; |
| |
| /** |
| * |
| */ |
| private static final long serialVersionUID = 1L; |
| |
| private final int changeType; |
| |
| private final Object oldValue; |
| |
| private final Object newValue; |
| |
| private final Object parent; |
| |
| private final int position; |
| |
| private boolean vetoed = false; |
| |
| /** |
| * @param source |
| * @param changeType |
| * @param oldValue |
| * @param newValue |
| */ |
| public ChangeEvent(Object source, int changeType, Object oldValue, |
| Object newValue) { |
| this(source, changeType, oldValue, newValue, POSITION_UNKNOWN); |
| } |
| |
| /** |
| * @param source |
| * @param changeType |
| * @param oldValue |
| * @param newValue |
| * @param position |
| */ |
| public ChangeEvent(Object source, int changeType, Object oldValue, |
| Object newValue, int position) { |
| this(source, changeType, oldValue, newValue, null, position); |
| } |
| |
| /** |
| * @param source |
| * @param changeType |
| * @param oldValue |
| * @param newValue |
| * @param parent |
| * @param position |
| */ |
| public ChangeEvent(Object source, int changeType, Object oldValue, |
| Object newValue, Object parent, int position) { |
| super(source); |
| this.oldValue = oldValue; |
| this.changeType = changeType; |
| this.newValue = newValue; |
| this.parent = parent; |
| this.position = position; |
| } |
| |
| /** |
| * Returns the change type (CHANGE, ADD, or REMOVE). |
| * |
| * @return the change type |
| */ |
| public int getChangeType() { |
| return changeType; |
| } |
| |
| /** |
| * Returns the value after the change, if available, or <code>null</code> |
| * if the change is a removal from a list. |
| * |
| * @return the new value, or null |
| */ |
| public Object getNewValue() { |
| return newValue; |
| } |
| |
| /** |
| * Returns the value before the change, if available, or <code>null</code> |
| * if the change is an addition to a list. |
| * |
| * @return the old value, or null |
| */ |
| public Object getOldValue() { |
| return oldValue; |
| } |
| |
| /** |
| * If the updatable is a list, return the position of the changed element, |
| * or POSITION_ALL if more than one element was changed, added or removed. |
| * The return value is unspecified if the updatable is not a list. |
| * |
| * @return the position of the changed element |
| */ |
| public int getPosition() { |
| return position; |
| } |
| |
| /** |
| * If the change event is of type VERIFY, this method returns true if this |
| * event has been vetoed by a listener. |
| * |
| * @return <code>true</code> if the change has been vetoed. |
| */ |
| public boolean getVeto() { |
| return vetoed; |
| } |
| |
| /** |
| * If the change event is of type VERIFY, listeners can call this method to |
| * veto the change. |
| * |
| * @param veto |
| */ |
| public void setVeto(boolean veto) { |
| vetoed = veto; |
| } |
| |
| /** |
| * parent is typically used with tree structures. |
| * @return parent |
| */ |
| public Object getParent() { |
| return parent; |
| } |
| |
| } |