com.safi.workshop.sqlexplorer.preferences.OverlaidPreferencePage.java Source code

Introduction

Here is the source code for com.safi.workshop.sqlexplorer.preferences.OverlaidPreferencePage.java

Source

/*
 * Copyright (C) 2007 SQL Explorer Development Team
 * http://sourceforge.net/projects/eclipsesql
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package com.safi.workshop.sqlexplorer.preferences;

import org.eclipse.jface.preference.FieldEditor;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;

import com.safi.workshop.sqlexplorer.plugin.SQLExplorerPlugin;

/**
 * Implementation of AbstractPreferencePage which uses the OverlayPreferenceStore as its
 * IPreferenceStore implementation. Derived classes should override createFieldEditors()
 * as normal, but also have to implement getSupportedPreferences(); you must list all
 * preference in the results of getSupportedPreferences().
 * 
 * OverlayPreferenceStore acts as a buffer between the controls onscreen and the
 * IPreferenceStore provided by Eclipse for us to persist the users choices to. When the
 * user clicks OK, the settings in the OverlayPreferenceStore are copied into the
 * Eclipse-provided store. This is useful because it allows us to feed the preference
 * store to other code so that we can preview the settings before they are commited.
 * 
 * The FieldEditor implementation assume that they have to keep the value until their
 * store() is called, so this is only really usefull if you need to preview settings
 * without persisting them back to Eclipse; if you do not need to preview then you should
 * use AbstractPreferencePage instead.
 * 
 * OverlayPreferenceStore was copied from the Eclipse source.
 * 
 * @author John Spackman
 */
public abstract class OverlaidPreferencePage extends AbstractPreferencePage {

    public OverlaidPreferencePage(int style) {
        super(style);
        initialise();
    }

    public OverlaidPreferencePage(String title, ImageDescriptor image, int style) {
        super(title, image, style);
        initialise();
    }

    public OverlaidPreferencePage(String title, int style) {
        super(title, style);
        initialise();
    }

    /**
     * Provides an EXHAUSTIVE list of preferences (ID plus type) that this page supports,
     * ANYTHING not listed will NOT be stored
     * 
     * @return
     */
    protected abstract OverlayPreferenceStore.OverlayKey[] getSupportedPreferences();

    /**
     * Initialises the overlay store, etc
     */
    protected void initialise() {
        // Create the new store and load values into it
        OverlayPreferenceStore store = new OverlayPreferenceStore(
                SQLExplorerPlugin.getDefault().getPreferenceStore(), getSupportedPreferences());
        store.start();
        store.load();

        // Set as default
        setPreferenceStore(store);
    }

    /**
     * Returns the OverlayPreferenceStore
     * 
     * @return
     */
    public OverlayPreferenceStore getOverlayStore() {
        return (OverlayPreferenceStore) super.getPreferenceStore();
    }

    /*
     * (non-JavaDoc)
     * 
     * @see org.eclipse.jface.preference.FieldEditorPreferencePage#dispose()
     */
    @Override
    public void dispose() {
        getOverlayStore().stop();
        super.dispose();
    }

    /*
     * (non-JavaDoc)
     * 
     * @see
     * org.eclipse.jface.preference.FieldEditorPreferencePage#addField(org.eclipse.jface
     * .preference.FieldEditor)
     */
    @Override
    protected void addField(final FieldEditor editor) {
        // Make sure that FieldEditors automatically write their changes straight to the store
        editor.setPropertyChangeListener(new IPropertyChangeListener() {
            public void propertyChange(PropertyChangeEvent event) {
                editor.store();
            }
        });
        super.addField(editor);
    }

    /*
     * (non-JavaDoc)
     * 
     * @see
     * com.safi.workshop.sqlexplorer.preferences.AbstractPreferencePage#performDefaults()
     */
    @Override
    protected void performDefaults() {
        super.performDefaults();
        getOverlayStore().loadDefaults();
    }

    /*
     * (non-JavaDoc)
     * 
     * @see com.safi.workshop.sqlexplorer.preferences.AbstractPreferencePage#performOk()
     */
    @Override
    public boolean performOk() {
        boolean ok = super.performOk();
        // Copy the overlay store into the Eclipse store
        if (ok)
            getOverlayStore().propagate();
        return ok;
    }
}