org.eclipse.egit.ui.internal.preferences.DoublePreferencesPreferencePage.java Source code

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Here is the source code for org.eclipse.egit.ui.internal.preferences.DoublePreferencesPreferencePage.java

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/*******************************************************************************
 * Copyright (C) 2017 Thomas Wolf <thomas.wolf@paranor.ch>
 *
 * 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
 *******************************************************************************/
package org.eclipse.egit.ui.internal.preferences;

import java.io.IOException;

import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.egit.ui.Activator;
import org.eclipse.jface.preference.FieldEditorPreferencePage;
import org.eclipse.jface.preference.IPersistentPreferenceStore;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.util.Policy;

/**
 * A {@link FieldEditorPreferencePage} that provides access to a secondary
 * {@link IPreferenceStore} and that takes care of storing that secondary store,
 * if necessary.
 */
public abstract class DoublePreferencesPreferencePage extends FieldEditorPreferencePage {

    private IPreferenceStore secondaryStore;

    /**
     * Creates a new {@link DoublePreferencesPreferencePage} with
     * {@link FieldEditorPreferencePage#FLAT FLAT} style and neither title nor
     * image.
     */
    public DoublePreferencesPreferencePage() {
        super(FLAT);
    }

    /**
     * Creates a new {@link DoublePreferencesPreferencePage} with the given
     * style and neither title nor image.
     *
     * @param style
     *            to use
     */
    protected DoublePreferencesPreferencePage(int style) {
        super(style);
    }

    /**
     * Creates a new {@link DoublePreferencesPreferencePage} with the given
     * style and title but without image.
     *
     * @param title
     *            for the page
     * @param style
     *            to use
     */
    protected DoublePreferencesPreferencePage(String title, int style) {
        super(title, style);
    }

    /**
     * Creates a new {@link DoublePreferencesPreferencePage} with the given
     * style, title, and image.
     *
     * @param title
     *            for the page
     * @param imageDescriptor
     *            for the image for the page
     * @param style
     *            to use
     */
    protected DoublePreferencesPreferencePage(String title, ImageDescriptor imageDescriptor, int style) {
        super(title, imageDescriptor, style);
    }

    /**
     * Returns the secondary preference store of this preference page.
     * <p>
     * This is a framework hook method for subclasses to return a page-specific
     * preference store. The default implementation returns {@code null}.
     * </p>
     *
     * @return the preference store, or {@code null} if none
     */
    protected IPreferenceStore doGetSecondaryPreferenceStore() {
        return null;
    }

    /**
     * Returns the secondary preference store of this preference page.
     *
     * @return the preference store, or {@code null} if none
     */
    public IPreferenceStore getSecondaryPreferenceStore() {
        if (secondaryStore == null) {
            secondaryStore = doGetSecondaryPreferenceStore();
        }
        return secondaryStore;
    }

    @Override
    public boolean performOk() {
        boolean isOk = super.performOk();
        if (isOk) {
            saveSecondaryPreferenceStore();
        }
        return isOk;
    }

    @Override
    public void dispose() {
        super.dispose();
        secondaryStore = null;
    }

    private void saveSecondaryPreferenceStore() {
        IPreferenceStore store = getSecondaryPreferenceStore();
        if (store != null && store.needsSaving() && (store instanceof IPersistentPreferenceStore)) {
            try {
                ((IPersistentPreferenceStore) store).save();
            } catch (IOException e) {
                String message = JFaceResources.format("PreferenceDialog.saveErrorMessage", //$NON-NLS-1$
                        new Object[] { getTitle(), e.getMessage() });
                Policy.getStatusHandler().show(new Status(IStatus.ERROR, Activator.getPluginId(), message, e),
                        JFaceResources.getString("PreferenceDialog.saveErrorTitle")); //$NON-NLS-1$
            }
        }
    }
}