/*******************************************************************************
* Copyright (c) 2007 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.wizard;
import java.util.Iterator;
import org.eclipse.core.databinding.AggregateValidationStatus;
import org.eclipse.core.databinding.Binding;
import org.eclipse.core.databinding.DataBindingContext;
import org.eclipse.core.databinding.observable.ChangeEvent;
import org.eclipse.core.databinding.observable.IChangeListener;
import org.eclipse.core.databinding.observable.list.IListChangeListener;
import org.eclipse.core.databinding.observable.list.ListChangeEvent;
import org.eclipse.core.databinding.observable.list.ListDiff;
import org.eclipse.core.databinding.observable.list.ListDiffEntry;
import org.eclipse.core.databinding.observable.value.IValueChangeListener;
import org.eclipse.core.databinding.observable.value.ValueChangeEvent;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.jface.wizard.WizardPage;
/**
* Connects the validation result from the given data binding context to the
* given wizard page, updating the wizard page's completion state and its error
* message accordingly.
*
* This class is not intended to be extended by clients.
*
* @since 1.1
*/
public class WizardPageSupport {
private WizardPage wizardPage;
private DataBindingContext dbc;
private AggregateValidationStatus aggregateStatus;
private boolean uiChanged = false;
/**
* Connect the validation result from the given data binding context to the
* given wizard page. Upon creation, the wizard page support will use the
* context's validation result to determine whether the page is complete.
* The page's error message will not be set at this time ensuring that the
* wizard page does not show an error right away. Upon any validation result
* change, {@link WizardPage#setPageComplete(boolean)} will be called
* reflecting the new validation result, and the wizard page's error message
* will be updated according to the current validation result.
*
* @param wizardPage
* @param dbc
* @return an instance of WizardPageSupport
*/
public static WizardPageSupport create(WizardPage wizardPage,
DataBindingContext dbc) {
return new WizardPageSupport(wizardPage, dbc);
}
private WizardPageSupport(WizardPage wizardPage, DataBindingContext dbc) {
this.wizardPage = wizardPage;
this.dbc = dbc;
init();
}
private IChangeListener uiChangeListener = new IChangeListener() {
public void handleChange(ChangeEvent event) {
handleUIChanged();
}
};
private IListChangeListener bindingsListener = new IListChangeListener() {
public void handleListChange(ListChangeEvent event) {
ListDiff diff = event.diff;
ListDiffEntry[] differences = diff.getDifferences();
for (int i = 0; i < differences.length; i++) {
ListDiffEntry listDiffEntry = differences[i];
Binding binding = (Binding) listDiffEntry.getElement();
if (listDiffEntry.isAddition()) {
binding.getTarget().addChangeListener(uiChangeListener);
} else {
binding.getTarget().removeChangeListener(uiChangeListener);
}
}
}
};
private IStatus currentStatus;
protected void init() {
aggregateStatus = new AggregateValidationStatus(dbc.getBindings(),
AggregateValidationStatus.MAX_SEVERITY);
aggregateStatus.addValueChangeListener(new IValueChangeListener() {
public void handleValueChange(ValueChangeEvent event) {
currentStatus = (IStatus) event.diff.getNewValue();
handleStatusChanged();
}
});
currentStatus = (IStatus) aggregateStatus.getValue();
handleStatusChanged();
dbc.getBindings().addListChangeListener(bindingsListener);
for (Iterator it = dbc.getBindings().iterator(); it.hasNext();) {
Binding binding = (Binding) it.next();
binding.getTarget().addChangeListener(uiChangeListener);
}
}
protected void handleUIChanged() {
uiChanged = true;
if (currentStatus != null) {
handleStatusChanged();
}
dbc.getBindings().removeListChangeListener(bindingsListener);
for (Iterator it = dbc.getBindings().iterator(); it.hasNext();) {
Binding binding = (Binding) it.next();
binding.getTarget().removeChangeListener(uiChangeListener);
}
}
protected void handleStatusChanged() {
if (currentStatus != null
&& currentStatus.getSeverity() == IStatus.ERROR) {
wizardPage.setPageComplete(false);
wizardPage.setErrorMessage(uiChanged ? currentStatus.getMessage()
: null);
} else {
wizardPage.setPageComplete(true);
wizardPage.setErrorMessage(null);
}
}
/**
* Disposes of this wizard page support object, removing any listeners it
* may have attached.
*/
public void dispose() {
aggregateStatus.dispose();
if (!uiChanged) {
for (Iterator it = dbc.getBindings().iterator(); it.hasNext();) {
Binding binding = (Binding) it.next();
binding.getTarget().removeChangeListener(uiChangeListener);
}
dbc.getBindings().removeListChangeListener(bindingsListener);
}
aggregateStatus = null;
dbc = null;
uiChangeListener = null;
bindingsListener = null;
wizardPage = null;
}
}