/*******************************************************************************
*
* Copyright (c) 2012 Google, Inc.
* 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:
* Google, Inc. - initial API and implementation
*******************************************************************************/
package com.swtdesigner;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.eclipse.jface.preference.FieldEditor;
import org.eclipse.jface.preference.PreferencePage;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
/**
* A special abstract preference page to host field editors and eny other controls
* with flexible layout.
* <p>
* Subclasses must implement the <code>createPageContents</code>.
* </p>
*
* This class may be freely distributed as part of any application or plugin.
* @version $Revision: 1.1 $
* @author scheglov_ke
*/
public abstract class FieldLayoutPreferencePage extends PreferencePage implements IPropertyChangeListener {
/**
* The field editors.
*/
private List fields = new ArrayList();
/**
* The first invalid field editor, or <code>null</code>
* if all field editors are valid.
*/
private FieldEditor invalidFieldEditor = null;
/**
* Creates a new field editor preference page with an empty title, and no image.
*/
protected FieldLayoutPreferencePage() {
}
/**
* Creates a new field editor preference page with the given title, but no image.
*
* @param title the title of this preference page
*/
protected FieldLayoutPreferencePage(String title) {
super(title);
}
/**
* Creates a new field editor preference page with the given image, and style.
*
* @param title the title of this preference page
* @param image the image for this preference page, or <code>null</code> if none
*/
protected FieldLayoutPreferencePage(String title, ImageDescriptor image) {
super(title, image);
}
/**
* Adds the given field editor to this page.
*
* @param editor the field editor
*/
protected void addField(FieldEditor editor) {
if (fields == null)
fields = new ArrayList();
fields.add(editor);
}
/**
* Recomputes the page's error state by calling <code>isValid</code> for
* every field editor.
*/
protected void checkState() {
boolean valid = true;
invalidFieldEditor = null;
// The state can only be set to true if all
// field editors contain a valid value. So we must check them all
if (fields != null) {
int size = fields.size();
for (int i = 0; i < size; i++) {
FieldEditor editor = (FieldEditor) fields.get(i);
valid = valid && editor.isValid();
if (!valid) {
invalidFieldEditor = editor;
break;
}
}
}
setValid(valid);
}
/* (non-Javadoc)
* Method declared on PreferencePage.
*/
protected Control createContents(Composite parent) {
Control contens = createPageContents(parent);
initialize();
checkState();
return contens;
}
/**
* Creates and returns the SWT control for the customized body
* of this preference page under the given parent composite.
* <p>
* This framework method must be implemented by concrete subclasses. Any
* subclass returning a <code>Composite</code> object whose <code>Layout</code>
* has default margins (for example, a <code>GridLayout</code>) are expected to
* set the margins of this <code>Layout</code> to 0 pixels.
* </p>
*
* @param parent the parent composite
* @return the new control
*/
protected abstract Control createPageContents(Composite parent);
/**
* The field editor preference page implementation of an <code>IDialogPage</code>
* method disposes of this page's controls and images.
* Subclasses may override to release their own allocated SWT
* resources, but must call <code>super.dispose</code>.
*/
public void dispose() {
super.dispose();
if (fields != null) {
Iterator e = fields.iterator();
while (e.hasNext()) {
FieldEditor pe = (FieldEditor) e.next();
/* $codepro.preprocessor.if version >= 3.1 $ */
pe.setPage(null);
/* $codepro.preprocessor.elseif version < 3.0 $
pe.setPreferencePage(null);
$codepro.preprocessor.endif $ */
pe.setPropertyChangeListener(null);
pe.setPreferenceStore(null);
}
}
}
/**
* Initializes all field editors.
*/
protected void initialize() {
if (fields != null) {
Iterator e = fields.iterator();
while (e.hasNext()) {
FieldEditor pe = (FieldEditor) e.next();
/* $codepro.preprocessor.if version >= 3.1 $ */
pe.setPage(null);
/* $codepro.preprocessor.elseif version < 3.0 $
pe.setPreferencePage(null);
$codepro.preprocessor.endif $ */
pe.setPropertyChangeListener(this);
pe.setPreferenceStore(getPreferenceStore());
pe.load();
}
}
}
/**
* The field editor preference page implementation of a <code>PreferencePage</code>
* method loads all the field editors with their default values.
*/
protected void performDefaults() {
if (fields != null) {
Iterator e = fields.iterator();
while (e.hasNext()) {
FieldEditor pe = (FieldEditor) e.next();
pe.loadDefault();
}
}
// Force a recalculation of my error state.
checkState();
super.performDefaults();
}
/**
* The field editor preference page implementation of this
* <code>PreferencePage</code> method saves all field editors by
* calling <code>FieldEditor.store</code>. Note that this method
* does not save the preference store itself; it just stores the
* values back into the preference store.
*
* @see FieldEditor#store()
*/
public boolean performOk() {
if (fields != null) {
Iterator e = fields.iterator();
while (e.hasNext()) {
FieldEditor pe = (FieldEditor) e.next();
pe.store();
}
}
return true;
}
/**
* The field editor preference page implementation of this <code>IPreferencePage</code>
* (and <code>IPropertyChangeListener</code>) method intercepts <code>IS_VALID</code>
* events but passes other events on to its superclass.
*/
public void propertyChange(PropertyChangeEvent event) {
if (event.getProperty().equals(FieldEditor.IS_VALID)) {
boolean newValue = ((Boolean) event.getNewValue()).booleanValue();
// If the new value is true then we must check all field editors.
// If it is false, then the page is invalid in any case.
if (newValue) {
checkState();
} else {
invalidFieldEditor = (FieldEditor) event.getSource();
setValid(newValue);
}
}
}
/* (non-Javadoc)
* Method declared on IDialog.
*/
public void setVisible(boolean visible) {
super.setVisible(visible);
if (visible && invalidFieldEditor != null) {
invalidFieldEditor.setFocus();
}
}
}