I am developing a multipage Form Editor to edit/create a customized XML file in Eclipse. structure is looks like:
- Implementation class is
MyXMLFormEditorwhich extends FormEditor. - Each page of FormEditor extends FormPage (i.e. MyXMLFormPage extends FormPage).
- Between FormEditor and actual XML file I am maintaining JDOM model.
- Also I implemented dirty flag handling. So user’s inputs into form editor gets saved into JDOM till the time user presses Save button. When user presses save button JDOM is written/serialized into XML file.
In an editor with above functionality I would like to implement undo/redo functionality as follow:
When editor is dirty (user changed something into form editor and it is not saved) undo operation should revert back the changes in form editor as well as JDOM to its original state (i.e. the state when editor was non-dirty) and redo operation should again bring back the changes into FormEditor as well as JDOM and editor should become dirty.
Following is my code snippet
MyXMLFormEditor.java
public class MyXMLFormEditor extends FormEditor {
MyXMLFormEditor(){
super();
}
@Override
protected FormToolkit createToolkit(Display display) {
// Create a toolkit that shares colors between editors.
return new FormToolkit(Activator.getDefault().getFormColors(display));
}
@Override
public void init(IEditorSite site, IEditorInput editorInput) {
setSite(site);
mSite = site;
setInput(editorInput);
try {
super.init(site, editorInput);
} catch (PartInitException e1) {
e1.printStackTrace();
}
if (!(editorInput instanceof IFileEditorInput))
try {
throw new PartInitException("Invalid Input: Must be IFileEditorInput");
} catch (PartInitException e) {
e.printStackTrace();
}
setPartName(fileName);
}
public void setUpProgFile(IEditorSite site, IEditorInput editorInput){
IFileEditorInput fileInput = ((IFileEditorInput) editorInput);
//create document builder and prepare JDom model for xml file.
}
@Override
protected void addPages() {
try {
//add 'Main' page
objMyXMLFormPage = new MyXMLFormPage (this, "FirstPage","Main");
//set rootNode of MyXMLFormPage
objMyXMLFormPage.rootNode = getRootNode();
objMyXMLFormPage.filePath = filePath;
objMyXMLFormPage.document = document;
addPage(objMyXMLFormPage);
} catch (PartInitException e) {
e.printStackTrace();
}
}
@Override
public void doSave(IProgressMonitor monitor) {
System.out.println("MyXMLFormEditor: doSave");
//logic to write jdom contents into xml file.
objMyXMLFormPage.setDirty(false);
}
@Override
public void doSaveAs() {
System.out.println("MyXMLFormEditor: doSaveAs");
}
@Override
public boolean isSaveAsAllowed() {
System.out.println("MyXMLFormEditor: isSaveAsAllowed");
return true;
}
}
MyXMLFormPage .java
public class MyXMLFormPage extends FormPage{
//private members declaration.
public MyXMLFormPage (MyXMLFormEditor editor,String title, String id) {
// initialize the editor and set its title and name.
super(editor,title,id );
}
@Override
public void createFormContent(IManagedForm managedForm) {
// Set page title
super.createFormContent(managedForm);
FormToolkit mMyXMLFormPage Toolkit = managedForm.getToolkit();
//Logic to creat UI and populating its contents from JDom
}
private void makeEditorDirty() {
updateJdom = true;
setDirty(true);
}
private void updateJDom() {
if(updateJdom){
System.out.println("*** Jdom updated ***");
updateJdom = false;
}
}
@Override
public boolean isDirty() {
return isDirtyFlag;
}
protected void setDirty(boolean value) {
isDirtyFlag = value;
dirtyStateChanged();
}
public void dirtyStateChanged() {
getEditor().editorDirtyStateChanged();
}
@Override
public boolean isSaveAsAllowed() {
System.out.println("MyXMLFormPage .isSaveAsAllowed");
return false;
}
@Override
public void doSave(IProgressMonitor monitor) {
System.out.println("MyXMLFormPage .doSave");
}
}
Can anyone provide me pointer/samples on how to implement undo/redo functionality into FormEditor? It would be good if the approach make use of existing undo/redo framework of Eclipse PDE or workbench.
