這一節我們來介紹如何在編輯器中移動活動，改變活動的大小和刪除活動，在流程控制器中已經安裝的策略WorkflowProcessXYLayoutEditPolicy，可以接受移動活動和改變活動大小的請求，但不能接受刪除活動的請求，要處理刪除活動的請求，必須在活動控制器中安裝策略。
我們還是先來看WorkflowProcessXYLayoutEditPolicy這個類，要實現改變活動大小和位置的功能，應該覆蓋父類的createChangeConstraintCommand方法，具體代碼如下：
/**ResizeorMoveAbstractActivityintheWorkflowProcessEditor*/
protected Command createChangeConstraintCommand(ChangeBoundsRequest request, EditPart child, Object constraint) {
if(child instanceof AbstractActivityEditPart && constraint instanceof Rectangle){
//return a command that can move and/or resize a AbstractActivity
returnnew AbstractActivitySetConstraintCommand(
(AbstractActivity)child.getModel(), request, (Rectangle) constraint);
}
returnsuper.createChangeConstraintCommand(request, child, constraint);
}
在這個方法中，我們創建一個AbstractActivitySetConstraintCommand命令，用這個命令來修改活動的位置，大小屬性，這個命令的具體代碼如下：
package com.example.workflow.commands;
import org.eclipse.draw2d.geometry.Rectangle;
import org.eclipse.gef.RequestConstants;
import org.eclipse.gef.commands.Command;
import org.eclipse.gef.requests.ChangeBoundsRequest;
import com.example.workflow.model.AbstractActivity;
/**
* A command to resize and/or move a shape.
* The command can be undone or redone.
*/
public class AbstractActivitySetConstraintCommand extends Command{
/** Stores the new size and location. */
private final Rectangle newBounds;
/** Stores the old size and location. */
private Rectangle oldBounds;
/** A request to move/resize an edit part. */
private final ChangeBoundsRequest request;
/** AbstractActivity to manipulate. */
private final AbstractActivity abstractActivity;
/**
* Create a command that can resize and/or move a AbstractActivity.
* @param abstractActivity the AbstractActivity to manipulate
* @param req the move and resize request
* @param newBounds the new size and location
* @throws IllegalArgumentException if any of the parameters is null
*/
public AbstractActivitySetConstraintCommand(AbstractActivity abstractActivity,
ChangeBoundsRequest req,Rectangle newBounds){
if (abstractActivity == null || req == null || newBounds == null) {
throw new IllegalArgumentException();
}
this.abstractActivity = abstractActivity;
this.request = req;
this.newBounds = newBounds.getCopy();
setLabel("move / resize");
}
/* (non-Javadoc)
* @see org.eclipse.gef.commands.Command#canExecute()
*/
public boolean canExecute() {
Object type = request.getType();
// make sure the Request is of a type we support:
return (RequestConstants.REQ_MOVE.equals(type)
|| RequestConstants.REQ_MOVE_CHILDREN.equals(type)
|| RequestConstants.REQ_RESIZE.equals(type)
|| RequestConstants.REQ_RESIZE_CHILDREN.equals(type));
}
/* (non-Javadoc)
* @see org.eclipse.gef.commands.Command#execute()
*/
public void execute() {
oldBounds = new Rectangle(abstractActivity.getLocation(), abstractActivity.getSize());
redo();
}
/* (non-Javadoc)
* @see org.eclipse.gef.commands.Command#redo()
*/
public void redo() {
abstractActivity.setSize(newBounds.getSize());
abstractActivity.setLocation(newBounds.getLocation());
}
/* (non-Javadoc)
* @see org.eclipse.gef.commands.Command#undo()
*/
public void undo() {
abstractActivity.setSize(oldBounds.getSize());
abstractActivity.setLocation(oldBounds.getLocation());
}
}
我們知道修改了活動的大小，位置屬性之後，活動模型會通知控制器它的LOCATION_PROP，SIZE_PROP發生變化，這可在模型的定義中看到：
publicvoid setLocation(Point newLocation) {
if (newLocation == null) {
thrownew IllegalArgumentException();
}
location.setLocation(newLocation);
firePropertyChange(LOCATION_PROP, null, location);
}
publicvoid setSize(Dimension newSize) {
if (newSize != null) {
size.setSize(newSize);
firePropertyChange(SIZE_PROP, null, size);
}
}
活動控制器AbstractActivityEditPart應該根據這些屬性的變化來刷新視圖，代碼如下：
publicvoid propertyChange(PropertyChangeEvent evt) {
String prop = evt.getPropertyName();
if(AbstractActivity.SIZE_PROP.equals(prop)
||AbstractActivity.LOCATION_PROP.equals(prop)){
refreshVisuals();
}
}
而refreshVisuals()方法我們已經在前面實現好了，這樣我們運行項目，就可以改變活動的位置和大小了，效果如下：
接下來，我們介紹如何在編輯器中刪除活動，要實現這功能，應該在活動控制器AbstractActivityEditPart中安裝能接受刪除活動請求的策略，代碼如下：
protectedvoid createEditPolicies() {
//allow removal of the associated model element
installEditPolicy(EditPolicy.COMPONENT_ROLE, new AbstractActivityComponentEditPolicy());
}
策略AbstractActivityComponentEditPolicy的代碼如下：
package com.example.workflow.policy;
import org.eclipse.gef.commands.Command;
import org.eclipse.gef.editpolicies.ComponentEditPolicy;
import org.eclipse.gef.requests.GroupRequest;
import com.example.workflow.commands.AbstractActivityDeleteCommand;
import com.example.workflow.model.AbstractActivity;
import com.example.workflow.model.WorkflowProcess;
public class AbstractActivityComponentEditPolicy extends ComponentEditPolicy{
protected Command createDeleteCommand(GroupRequest deleteRequest) {
Object parent = getHost().getParent().getModel();
Object child = getHost().getModel();
if(parent instanceof WorkflowProcess && child instanceof AbstractActivity){
return new AbstractActivityDeleteCommand((WorkflowProcess)parent,(AbstractActivity)child);
}
return super.createDeleteCommand(deleteRequest);
}
}
這個策略繼承了ComponentEditPolicy類，並且覆蓋了createDeleteCommand方法，在這個方法中，我們創建了AbstractActivityDeleteCommand命令，這個命令完成從流程模型中刪除當前活動模型，我們知道在活動模型中，還維護着輸入轉移和輸出轉移兩個列表，而轉移對象中又維護着轉移的起始活動和終止活動，由於刪除了活動，轉移就成了只有源點或者只要目標點，因此，我們還應該從還維護着這些轉移的活動中刪除這些轉移，該命令的代碼如下：
package com.example.workflow.commands;
import java.util.Iterator;
import java.util.List;
import org.eclipse.gef.commands.Command;
import com.example.workflow.model.AbstractActivity;
import com.example.workflow.model.Transition;
import com.example.workflow.model.WorkflowProcess;
/**
* A command to remove a AbstractActivity from its parent.
* The command can be undone or redone.
*/
public class AbstractActivityDeleteCommand extends Command{
/** AbstractActivity to remove. */
private final AbstractActivity child;
/** WorkflowProcess to remove from. */
private final WorkflowProcess parent;
/** Holds a copy of the outgoing transitions of child. */
private List sourceTransitions;
/** Holds a copy of the incoming transitions of child. */
private List targetTransitions;
/** True, if child was removed from its parent. */
private boolean wasRemoved;
/**
* Create a command that will remove the AbstractActivity from its parent.
* @param parent the WorkflowProcess containing the child
* @param child the AbstractActivity to remove
* @throws IllegalArgumentException if any parameter is null
*/
public AbstractActivityDeleteCommand(WorkflowProcess parent, AbstractActivity child) {
if (parent == null || child == null) {
throw new IllegalArgumentException();
}
setLabel("activity deletion");
this.parent = parent;
this.child = child;
}
/**
* Reconnects a List of Transitions with their previous endpoints.
* @param transitions a non-null List of connections
*/
private void addConnections(List transitions) {
for (Iterator iter = transitions.iterator(); iter.hasNext();) {
Transition tran = (Transition) iter.next();
tran.reconnect();
}
}
/* (non-Javadoc)
* @see org.eclipse.gef.commands.Command#canUndo()
*/
public boolean canUndo() {
return wasRemoved;
}
/* (non-Javadoc)
* @see org.eclipse.gef.commands.Command#execute()
*/
public void execute() {
// store a copy of incoming & outgoing transitions before proceeding
sourceTransitions = child.getSourceTransitions();
targetTransitions = child.getTargetTransitions();
redo();
}
/* (non-Javadoc)
* @see org.eclipse.gef.commands.Command#redo()
*/
public void redo() {
// remove the child and disconnect its connections
wasRemoved = parent.removeChild(child);
if (wasRemoved) {
removeTransitions(sourceTransitions);
removeTransitions(targetTransitions);
}
}
/**
* Disconnects a List of Transitions from their endpoints.
* @param transitions a non-null List of transitions
*/
private void removeTransitions(List transitions) {
for (Iterator iter = transitions.iterator(); iter.hasNext();) {
Transition tran = (Transition) iter.next();
tran.disconnect();
}
}
/* (non-Javadoc)
* @see org.eclipse.gef.commands.Command#undo()
*/
public void undo() {
// add the child and reconnect its transitions
if (parent.addChild(child)) {
addConnections(sourceTransitions);
addConnections(targetTransitions);
}
}
}
這個命令中從流程模型中刪除了活動模型，流程模型通知控制器，它的CHILD_REMOVED_PROP屬性發生了變化，要控制器刷新它維護的活動集。
要實現刪除操作，我們必須通過刪除菜單或者鍵盤的刪除鍵，但現在編輯器還不支持這些功能，無論是通過刪除菜單還是刪除鍵，都是執行了一個Action，由這個Action來執行我們定義的刪除命令（關於Action和菜單的實現，我們在以後會講），這兒只介紹如何讓編輯器支持鍵盤操作，要實現鍵盤操作，在WorkflowProcessEditor類中定義一個KeyHandler 類型的成員變量sharedKeyHandler;
接下來定義一個方法：
protected KeyHandler getCommonKeyHandler() {
if (sharedKeyHandler == null) {
sharedKeyHandler = new KeyHandler();
sharedKeyHandler.put(
KeyStroke.getPressed(SWT.DEL, 127, 0),
getActionRegistry().getAction(ActionFactory.DELETE.getId()));
}
returnsharedKeyHandler;
}
該方法的作用是定義我們支持的鍵名，上面定義了刪除鍵，並且把這個鍵和刪除Action邦定，當按刪除鍵，就執行對應的Action，sharedKeyHandler可以供編輯器和大綱視圖公用，關於大綱視圖在以後會講。
接下來還需要在編輯器視圖中註冊這些這些公共鍵，代碼如下：
protectedvoid configureGraphicalViewer() {
super.configureGraphicalViewer();
GraphicalViewer viewer = getGraphicalViewer();
viewer.setEditPartFactory(new WorkflowProcessEditPartFactory());
viewer.setRootEditPart(new ScalableFreeformRootEditPart());
getGraphicalViewer().setKeyHandler(new GraphicalViewerKeyHandler(getGraphicalViewer())
.setParent(getCommonKeyHandler()));
}
這樣運行項目，我們就可以用鍵盤的刪除鍵來刪除活動了，我們注意到無論我們向編輯器中增加活動，還是刪除活動，編輯器的狀態始終沒變，不像其它編輯器修改之後，提示編輯器處於未保存狀態，我們要實現這個功能其實很簡單，只需在WorkflowProcessEditor類中覆蓋父類的方法commandStackChanged，代碼如下：
publicvoid commandStackChanged(EventObject event) {
firePropertyChange(IEditorPart.PROP_DIRTY);
super.commandStackChanged(event);
}
其實這個方法的原理很簡單，當編輯器的命令堆棧發生改變時，修改編輯器狀態爲未保存。我們知道我們進行增加活動，刪除活動等操作時，都是執行了一個個命令，而這些命令都保存在編輯器的命令堆棧裏，所以我們每執行一個命令，編輯器的命令堆棧就發生改變。
再運行項目，我們就可以看到在編輯器處於已保存狀態時，我們再進行操作，例如增加活動，刪除活動，編輯器的狀態就變成未保存了，至於在未保存狀態，點保存按鈕，還是未保存，這在以後，我們會解決。下一節，我們將介紹如何在活動之間增加和刪除轉移，如何在轉移上增加拐點。