Cleaning up preferences-related code.

diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/PreferenceAndPropertyPage.java b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/PreferenceAndPropertyPage.java
index 9d9c461..cb22c3a 100644
--- a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/PreferenceAndPropertyPage.java
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/PreferenceAndPropertyPage.java

@@ -8,6 +8,7 @@
  */
 package com.google.eclipse.protobuf.ui.preferences.pages;
 
+import static com.google.eclipse.protobuf.ui.preferences.binding.BindingToButtonSelection.bindSelectionOf;
 import static com.google.eclipse.protobuf.ui.preferences.pages.Messages.*;
 import static org.eclipse.ui.dialogs.PreferencesUtil.createPreferenceDialogOn;
 
@@ -23,6 +24,7 @@
 import org.eclipse.ui.*;
 import org.eclipse.xtext.ui.editor.preferences.IPreferenceStoreAccess;
 
+import com.google.eclipse.protobuf.ui.preferences.BooleanPreference;
 import com.google.eclipse.protobuf.ui.preferences.binding.PreferenceBinder;
 import com.google.inject.Inject;
 
@@ -33,7 +35,7 @@
  */
 public abstract class PreferenceAndPropertyPage extends PreferencePage implements IWorkbenchPreferencePage, IWorkbenchPropertyPage {
 
-  protected Button btnEnableProjectSettings;
+  private Button btnEnableProjectSettings;
 
   private Link lnkEnableWorkspaceSettings;
 
@@ -47,6 +49,7 @@
   @Override protected final Control createContents(Composite parent) {
     Composite contents = contentParent(parent);
     doCreateContents(contents);
+    setupBtnEnabledProjectSettingsBinding();
     setupBinding(preferenceBinder);
     preferenceBinder.applyValues();
     updateContents();
@@ -117,6 +120,21 @@
    */
   protected abstract void doCreateContents(Composite parent);
 
+  private void setupBtnEnabledProjectSettingsBinding() {
+    BooleanPreference preference = enableProjectSettingsPreference(getPreferenceStore());
+    if (preference == null) return;
+    preferenceBinder.add(bindSelectionOf(btnEnableProjectSettings).to(preference));
+  }
+
+  /**
+   * Returns the preference that indicates whether this page is a "Project Properties" or a "Workspace Preferences"
+   * page.
+   * @param store the store where the preference value is stored.
+   * @return the preference that indicates whether this page is a "Project Properties" or a "Workspace Preferences"
+   * page.
+   */
+  protected abstract BooleanPreference enableProjectSettingsPreference(IPreferenceStore store);
+
   /**
    * Sets up data binding.
    * @param preferenceBinder the preference binder;
@@ -155,9 +173,9 @@
   }
 
   /**
-   * Indicates whether this page is a "Project Properties" page or not.
+   * Indicates whether this page is a "Project Properties" or a "Workspace Preferences" page.
    * @return {@code true} if this page is a "Project Properties" page, or {@code false} if this page is a
-   * "Workspace Settings" page.
+   * "Workspace Preferences" page.
    */
   protected final boolean isPropertyPage() {
     return project != null;
@@ -201,13 +219,9 @@
 
   @Override public final boolean performOk() {
     preferenceBinder.saveValues();
-    okPerformed();
     return true;
   }
 
-  /** Method invoked after this page's defaults have been saved. By default this method does nothing. */
-  protected void okPerformed() {}
-
   @Override protected final void performDefaults() {
     preferenceBinder.applyDefaults();
     updateContents();

diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/CompilerPreferencePage.java b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/CompilerPreferencePage.java
index 81c9908..50b0976 100644
--- a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/CompilerPreferencePage.java
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/CompilerPreferencePage.java

@@ -11,6 +11,7 @@
 import static com.google.eclipse.protobuf.ui.preferences.binding.BindingToButtonSelection.bindSelectionOf;
 import static com.google.eclipse.protobuf.ui.preferences.binding.BindingToTextValue.bindTextOf;
 import static com.google.eclipse.protobuf.ui.preferences.pages.compiler.BindingToCodeGeneration.bindCodeGeneration;
+import static com.google.eclipse.protobuf.ui.preferences.pages.compiler.EnableProjectSettingsPreference.enableProjectSettings;
 import static com.google.eclipse.protobuf.ui.preferences.pages.compiler.Messages.*;
 import static com.google.eclipse.protobuf.ui.swt.EventListeners.addSelectionListener;
 import static java.util.Arrays.asList;
@@ -18,13 +19,14 @@
 
 import java.io.File;
 
+import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.*;
 import org.eclipse.swt.layout.*;
 import org.eclipse.swt.widgets.*;
 import org.eclipse.xtext.ui.PluginImageHelper;
 
-import com.google.eclipse.protobuf.ui.preferences.DataChangedListener;
+import com.google.eclipse.protobuf.ui.preferences.*;
 import com.google.eclipse.protobuf.ui.preferences.binding.PreferenceBinder;
 import com.google.eclipse.protobuf.ui.preferences.pages.PreferenceAndPropertyPage;
 import com.google.inject.Inject;
@@ -194,11 +196,12 @@
     pageIsNowValid();
   }
 
+  @Override protected BooleanPreference enableProjectSettingsPreference(IPreferenceStore store) {
+    return enableProjectSettings(store);
+  }
+
   @Override protected void setupBinding(PreferenceBinder preferenceBinder) {
     RawPreferences preferences = new RawPreferences(getPreferenceStore());
-    if (isPropertyPage()) {
-      preferenceBinder.add(bindSelectionOf(btnEnableProjectSettings).to(preferences.enableProjectSettings()));
-    }
     preferenceBinder.addAll(
         bindSelectionOf(btnCompileProtoFiles).to(preferences.compileProtoFiles()),
         bindSelectionOf(btnUseProtocInSystemPath).to(preferences.useProtocInSystemPath()),

diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/CompilerPreferenceStoreInitializer.java b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/CompilerPreferenceStoreInitializer.java
index 4e2b046..23d49f7 100644
--- a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/CompilerPreferenceStoreInitializer.java
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/CompilerPreferenceStoreInitializer.java

@@ -8,6 +8,8 @@
  */
 package com.google.eclipse.protobuf.ui.preferences.pages.compiler;
 
+import static com.google.eclipse.protobuf.ui.preferences.pages.compiler.EnableProjectSettingsPreference.enableProjectSettings;
+
 import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.xtext.ui.editor.preferences.*;
 
@@ -23,8 +25,8 @@
   /** {@inheritDoc} */
   public void initialize(IPreferenceStoreAccess access) {
     IPreferenceStore store = access.getWritablePreferenceStore();
+    enableProjectSettings(store).defaultValue(false);
     RawPreferences preferences = new RawPreferences(store);
-    preferences.enableProjectSettings().defaultValue(false);
     preferences.useProtocInSystemPath().defaultValue(true);
     preferences.javaCodeGenerationEnabled().defaultValue(false);
     preferences.cppCodeGenerationEnabled().defaultValue(false);

diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/CompilerPreferencesProvider.java b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/CompilerPreferencesProvider.java
index 658fc05..1b5ca2f 100644
--- a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/CompilerPreferencesProvider.java
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/CompilerPreferencesProvider.java

@@ -8,6 +8,8 @@
  */
 package com.google.eclipse.protobuf.ui.preferences.pages.compiler;
 
+import static com.google.eclipse.protobuf.ui.preferences.pages.compiler.EnableProjectSettingsPreference.enableProjectSettings;
+
 import org.eclipse.core.resources.IProject;
 import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.xtext.ui.editor.preferences.IPreferenceStoreAccess;
@@ -25,8 +27,7 @@
 
   public CompilerPreferences getPreferences(IProject project) {
     IPreferenceStore store = storeAccess.getWritablePreferenceStore(project);
-    RawPreferences preferences = new RawPreferences(store);
-    boolean useProjectPreferences = preferences.enableProjectSettings().value();
+    boolean useProjectPreferences = enableProjectSettings(store).value();
     if (!useProjectPreferences) store = storeAccess.getWritablePreferenceStore();
     return new CompilerPreferences(new RawPreferences(store));
   }

diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/EnableProjectSettingsPreference.java b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/EnableProjectSettingsPreference.java
new file mode 100644
index 0000000..a21d9a8
--- /dev/null
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/EnableProjectSettingsPreference.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2011 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
+ */
+package com.google.eclipse.protobuf.ui.preferences.pages.compiler;
+
+import org.eclipse.jface.preference.IPreferenceStore;
+
+import com.google.eclipse.protobuf.ui.preferences.BooleanPreference;
+
+/**
+ * @author alruiz@google.com (Alex Ruiz)
+ */
+class EnableProjectSettingsPreference {
+
+  static BooleanPreference enableProjectSettings(IPreferenceStore store) {
+    return new BooleanPreference("compiler.enableProjectSettings", store);
+  }
+
+  private EnableProjectSettingsPreference() {}
+}

diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/RawPreferences.java b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/RawPreferences.java
index 1394d3b..6336819 100644
--- a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/RawPreferences.java
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/compiler/RawPreferences.java

@@ -17,7 +17,6 @@
  */
 class RawPreferences {
 
-  private final BooleanPreference enableProjectSettings;
   private final BooleanPreference compileProtoFiles;
   private final BooleanPreference useProtocInSystemPath;
   private final BooleanPreference useProtocInCustomPath;
@@ -33,7 +32,6 @@
   private final BooleanPreference refreshOutputDirectory;
 
   RawPreferences(IPreferenceStore store) {
-    enableProjectSettings = new BooleanPreference("compiler.enableProjectSettings", store);
     compileProtoFiles = new BooleanPreference("compiler.compileProtoFiles", store);
     useProtocInSystemPath = new BooleanPreference("compiler.useProtocInSystemPath", store);
     useProtocInCustomPath = new BooleanPreference("compiler.useProtocInCustomPath", store);
@@ -49,10 +47,6 @@
     refreshOutputDirectory = new BooleanPreference("compiler.refreshOutputDirectory", store);
   }
 
-  BooleanPreference enableProjectSettings() {
-    return enableProjectSettings;
-  }
-
   BooleanPreference compileProtoFiles() {
     return compileProtoFiles;
   }

diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/general/GeneralSettingsPreferencePage.java b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/general/GeneralSettingsPreferencePage.java
index ef637d1..f07ba22 100644
--- a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/general/GeneralSettingsPreferencePage.java
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/general/GeneralSettingsPreferencePage.java

@@ -8,10 +8,12 @@
  */
 package com.google.eclipse.protobuf.ui.preferences.pages.general;
 
+import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.layout.*;
 import org.eclipse.swt.widgets.*;
 
+import com.google.eclipse.protobuf.ui.preferences.BooleanPreference;
 import com.google.eclipse.protobuf.ui.preferences.binding.PreferenceBinder;
 import com.google.eclipse.protobuf.ui.preferences.pages.PreferenceAndPropertyPage;
 
@@ -35,6 +37,11 @@
   }
 
   /** {@inheritDoc} */
+  @Override protected BooleanPreference enableProjectSettingsPreference(IPreferenceStore store) {
+    return null;
+  }
+
+  /** {@inheritDoc} */
   @Override protected void setupBinding(PreferenceBinder preferenceBinder) {}
 
   /** {@inheritDoc} */

diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/paths/PathsPreferencePage.java b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/paths/PathsPreferencePage.java
index 3c5f8d0..5d96567 100644
--- a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/paths/PathsPreferencePage.java
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/paths/PathsPreferencePage.java

@@ -18,6 +18,7 @@
 import java.util.*;
 import java.util.List;
 
+import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.*;
 import org.eclipse.swt.layout.*;
@@ -97,6 +98,10 @@
     pageIsNowValid();
   }
 
+  @Override protected BooleanPreference enableProjectSettingsPreference(IPreferenceStore store) {
+    return null; // this page is always a "Project Properties" page
+  }
+
   @Override protected void setupBinding(PreferenceBinder preferenceBinder) {
     RawPreferences preferences = new RawPreferences(getPreferenceStore());
     preferenceBinder.addAll(