org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/preferences/DoublePreferencesPreferencePage.java

   1 /*******************************************************************************
   2  * Copyright (C) 2017 Thomas Wolf <thomas.wolf@paranor.ch>
   3  *
   4  * All rights reserved. This program and the accompanying materials
   5  * are made available under the terms of the Eclipse Public License 2.0
   6  * which accompanies this distribution, and is available at
   7  * https://www.eclipse.org/legal/epl-2.0/
   8  *
   9  * SPDX-License-Identifier: EPL-2.0
  10  *******************************************************************************/
  11 package org.eclipse.egit.ui.internal.preferences;
  12
  13 import java.io.IOException;
  14
  15 import org.eclipse.core.runtime.IStatus;
  16 import org.eclipse.core.runtime.Status;
  17 import org.eclipse.egit.ui.Activator;
  18 import org.eclipse.jface.preference.FieldEditorPreferencePage;
  19 import org.eclipse.jface.preference.IPersistentPreferenceStore;
  20 import org.eclipse.jface.preference.IPreferenceStore;
  21 import org.eclipse.jface.resource.ImageDescriptor;
  22 import org.eclipse.jface.resource.JFaceResources;
  23 import org.eclipse.jface.util.Policy;
  24
  25 /**
  26  * A {@link FieldEditorPreferencePage} that provides access to a secondary
  27  * {@link IPreferenceStore} and that takes care of storing that secondary store,
  28  * if necessary.
  29  */
  30 public abstract class DoublePreferencesPreferencePage
  31                 extends FieldEditorPreferencePage {
  32
  33         private IPreferenceStore secondaryStore;
  34
  35         /**
  36          * Creates a new {@link DoublePreferencesPreferencePage} with
  37          * {@link FieldEditorPreferencePage#FLAT FLAT} style and neither title nor
  38          * image.
  39          */
  40         public DoublePreferencesPreferencePage() {
  41                 super(FLAT);
  42         }
  43
  44         /**
  45          * Creates a new {@link DoublePreferencesPreferencePage} with the given
  46          * style and neither title nor image.
  47          *
  48          * @param style
  49          *            to use
  50          */
  51         protected DoublePreferencesPreferencePage(int style) {
  52                 super(style);
  53         }
  54
  55         /**
  56          * Creates a new {@link DoublePreferencesPreferencePage} with the given
  57          * style and title but without image.
  58          *
  59          * @param title
  60          *            for the page
  61          * @param style
  62          *            to use
  63          */
  64         protected DoublePreferencesPreferencePage(String title, int style) {
  65                 super(title, style);
  66         }
  67
  68         /**
  69          * Creates a new {@link DoublePreferencesPreferencePage} with the given
  70          * style, title, and image.
  71          *
  72          * @param title
  73          *            for the page
  74          * @param imageDescriptor
  75          *            for the image for the page
  76          * @param style
  77          *            to use
  78          */
  79         protected DoublePreferencesPreferencePage(String title,
  80                         ImageDescriptor imageDescriptor, int style) {
  81                 super(title, imageDescriptor, style);
  82         }
  83
  84         /**
  85          * Returns the secondary preference store of this preference page.
  86          * <p>
  87          * This is a framework hook method for subclasses to return a page-specific
  88          * preference store. The default implementation returns {@code null}.
  89          * </p>
  90          *
  91          * @return the preference store, or {@code null} if none
  92          */
  93         protected IPreferenceStore doGetSecondaryPreferenceStore() {
  94                 return null;
  95         }
  96
  97         /**
  98          * Returns the secondary preference store of this preference page.
  99          *
 100          * @return the preference store, or {@code null} if none
 101          */
 102         public IPreferenceStore getSecondaryPreferenceStore() {
 103                 if (secondaryStore == null) {
 104                         secondaryStore = doGetSecondaryPreferenceStore();
 105                 }
 106                 return secondaryStore;
 107         }
 108
 109         @Override
 110         public boolean performOk() {
 111                 boolean isOk = super.performOk();
 112                 if (isOk) {
 113                         saveSecondaryPreferenceStore();
 114                 }
 115                 return isOk;
 116         }
 117
 118         @Override
 119         public void dispose() {
 120                 super.dispose();
 121                 secondaryStore = null;
 122         }
 123
 124         private void saveSecondaryPreferenceStore() {
 125                 IPreferenceStore store = getSecondaryPreferenceStore();
 126                 if (store != null && store.needsSaving()
 127                                 && (store instanceof IPersistentPreferenceStore)) {
 128                         try {
 129                                 ((IPersistentPreferenceStore) store).save();
 130                         } catch (IOException e) {
 131                                 String message = JFaceResources.format(
 132                                                 "PreferenceDialog.saveErrorMessage", //$NON-NLS-1$
 133                                                 new Object[] { getTitle(), e.getMessage() });
 134                                 Policy.getStatusHandler().show(
 135                                                 new Status(IStatus.ERROR, Activator.getPluginId(),
 136                                                                 message, e),
 137                                                 JFaceResources
 138                                                                 .getString("PreferenceDialog.saveErrorTitle")); //$NON-NLS-1$
 139                         }
 140                 }
 141         }
 142 }