walletfx: Introduce OverlayWindowController interface

Rationale:

1. Stronger typing makes code more readable and refactorable
2. Eliminates “automatic” reflection in MainController
3. Makes overlayUI field in implementing classes private
4. Is a step towards further refactoring and reusability

wallettemplate/src/main/java/org/bitcoinj/walletfx/overlay/OverlayWindowController.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright by the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.bitcoinj.walletfx.overlay;
+
+import wallettemplate.MainController;
+
+/**
+ * Interface for controllers displayed via OverlayWindow.OverlayUI
+ */
+public interface OverlayWindowController<T> {
+    /**
+     * @param ui The overlay UI (node, controller pair)
+     */
+    void setOverlayUI(MainController.OverlayUI<? extends OverlayWindowController<T>> ui);
+}

wallettemplate/src/main/java/wallettemplate/MainController.java

@@ -36,12 +36,12 @@ import javafx.scene.control.Button;
 import javafx.scene.control.Label;
 import javafx.scene.layout.HBox;
 import javafx.util.Duration;
+import org.bitcoinj.walletfx.overlay.OverlayWindowController;
 import org.bitcoinj.walletfx.utils.GuiUtils;
 import org.bitcoinj.walletfx.utils.TextFieldValidator;
 import wallettemplate.controls.ClickableBitcoinAddress;
 import wallettemplate.controls.NotificationBarPane;
 import org.bitcoinj.walletfx.utils.BitcoinUIModel;
-import org.bitcoinj.walletfx.utils.GuiUtils;
 import org.bitcoinj.walletfx.utils.easing.EasingMode;
 import org.bitcoinj.walletfx.utils.easing.ElasticInterpolator;
 
@@ -170,7 +170,7 @@ public class MainController {
         return model.getDownloadProgressTracker();
     }
 
-    public class OverlayUI<T> {
+    public class OverlayUI<T extends OverlayWindowController<T>> {
         public Node ui;
         public T controller;
 
@@ -219,22 +219,18 @@ public class MainController {
     }
 
     @Nullable
-    private OverlayUI currentOverlay;
+    private OverlayUI<? extends OverlayWindowController<?>> currentOverlay;
 
-    public <T> OverlayUI<T> overlayUI(Node node, T controller) {
+    public <T extends OverlayWindowController<T>> OverlayUI<T> overlayUI(Node node, T controller) {
         checkGuiThread();
         OverlayUI<T> pair = new OverlayUI<>(node, controller);
-        // Auto-magically set the overlayUI member, if it's there.
-        try {
-            controller.getClass().getField("overlayUI").set(controller, pair);
-        } catch (IllegalAccessException | NoSuchFieldException ignored) {
-        }
+        controller.setOverlayUI(pair);
         pair.show();
         return pair;
     }
 
     /** Loads the FXML file with the given name, blurs out the main UI and puts this one on top. */
-    public <T> OverlayUI<T> overlayUI(String name) {
+    public <T extends OverlayWindowController<T>> OverlayUI<T> overlayUI(String name) {
         try {
             checkGuiThread();
             // Load the UI from disk.
@@ -243,13 +239,7 @@ public class MainController {
             Pane ui = loader.load();
             T controller = loader.getController();
             OverlayUI<T> pair = new OverlayUI<>(ui, controller);
-            // Auto-magically set the overlayUI member, if it's there.
-            try {
-                if (controller != null)
-                    controller.getClass().getField("overlayUI").set(controller, pair);
-            } catch (IllegalAccessException | NoSuchFieldException ignored) {
-                ignored.printStackTrace();
-            }
+            controller.setOverlayUI(pair);
             pair.show();
             return pair;
         } catch (IOException e) {

wallettemplate/src/main/java/wallettemplate/SendMoneyController.java

@@ -29,6 +29,7 @@ import javafx.event.ActionEvent;
 import javafx.scene.control.Button;
 import javafx.scene.control.Label;
 import javafx.scene.control.TextField;
+import org.bitcoinj.walletfx.overlay.OverlayWindowController;
 import org.bouncycastle.crypto.params.KeyParameter;
 import wallettemplate.controls.BitcoinAddressValidator;
 import org.bitcoinj.walletfx.utils.TextFieldValidator;
@@ -39,7 +40,7 @@ import static org.bitcoinj.walletfx.utils.GuiUtils.*;
 
 import javax.annotation.Nullable;
 
-public class SendMoneyController {
+public class SendMoneyController implements OverlayWindowController<SendMoneyController> {
     public Button sendBtn;
     public Button cancelBtn;
     public TextField address;
@@ -47,11 +48,16 @@ public class SendMoneyController {
     public TextField amountEdit;
     public Label btcLabel;
 
-    public MainController.OverlayUI overlayUI;
+    private MainController.OverlayUI<? extends OverlayWindowController<SendMoneyController>> overlayUI;
 
     private Wallet.SendResult sendResult;
     private KeyParameter aesKey;
 
+    @Override
+    public void setOverlayUI(MainController.OverlayUI<? extends OverlayWindowController<SendMoneyController>> ui) {
+        overlayUI = ui;
+    }
+
     // Called by FXMLLoader
     public void initialize() {
         Coin balance = Main.bitcoin.wallet().getBalance();

wallettemplate/src/main/java/wallettemplate/WalletPasswordController.java

@@ -30,6 +30,7 @@ import javafx.scene.control.ProgressIndicator;
 import javafx.scene.image.ImageView;
 import javafx.scene.layout.GridPane;
 import javafx.scene.layout.HBox;
+import org.bitcoinj.walletfx.overlay.OverlayWindowController;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.bouncycastle.crypto.params.KeyParameter;
@@ -44,7 +45,7 @@ import static org.bitcoinj.walletfx.utils.GuiUtils.*;
  * User interface for entering a password on demand, e.g. to send money. Also used when encrypting a wallet. Shows a
  * progress meter as we scrypt the password.
  */
-public class WalletPasswordController {
+public class WalletPasswordController implements OverlayWindowController<WalletPasswordController> {
     private static final Logger log = LoggerFactory.getLogger(WalletPasswordController.class);
 
     @FXML HBox buttonsBox;
@@ -54,10 +55,15 @@ public class WalletPasswordController {
     @FXML GridPane widgetGrid;
     @FXML Label explanationLabel;
 
-    public MainController.OverlayUI overlayUI;
+    private MainController.OverlayUI<? extends OverlayWindowController<WalletPasswordController>> overlayUI;
 
     private SimpleObjectProperty<KeyParameter> aesKey = new SimpleObjectProperty<>();
 
+    @Override
+    public void setOverlayUI(MainController.OverlayUI<? extends OverlayWindowController<WalletPasswordController>> ui) {
+        overlayUI = ui;
+    }
+
     public void initialize() {
         progressMeter.setOpacity(0);
         Platform.runLater(pass1::requestFocus);

wallettemplate/src/main/java/wallettemplate/WalletSetPasswordController.java

@@ -23,6 +23,7 @@ import javafx.scene.control.*;
 import javafx.scene.layout.*;
 import org.bitcoinj.crypto.*;
 import org.bitcoinj.wallet.*;
+import org.bitcoinj.walletfx.overlay.OverlayWindowController;
 import org.slf4j.*;
 import org.bouncycastle.crypto.params.*;
 
@@ -34,7 +35,7 @@ import java.util.concurrent.*;
 import org.bitcoinj.walletfx.utils.KeyDerivationTasks;
 import static org.bitcoinj.walletfx.utils.GuiUtils.*;
 
-public class WalletSetPasswordController {
+public class WalletSetPasswordController implements OverlayWindowController<WalletSetPasswordController> {
     private static final Logger log = LoggerFactory.getLogger(WalletSetPasswordController.class);
     public PasswordField pass1, pass2;
 
@@ -43,7 +44,7 @@ public class WalletSetPasswordController {
     public Button closeButton;
     public Label explanationLabel;
 
-    public MainController.OverlayUI overlayUI;
+    private MainController.OverlayUI<? extends OverlayWindowController<WalletSetPasswordController>> overlayUI;
     // These params were determined empirically on a top-range (as of 2014) MacBook Pro with native scrypt support,
     // using the scryptenc command line tool from the original scrypt distribution, given a memory limit of 40mb.
     public static final Protos.ScryptParameters SCRYPT_PARAMETERS = Protos.ScryptParameters.newBuilder()
@@ -53,6 +54,11 @@ public class WalletSetPasswordController {
             .setSalt(ByteString.copyFrom(KeyCrypterScrypt.randomSalt()))
             .build();
 
+    @Override
+    public void setOverlayUI(MainController.OverlayUI<? extends OverlayWindowController<WalletSetPasswordController>> ui) {
+        overlayUI = ui;
+    }
+
     public void initialize() {
         progressMeter.setOpacity(0);
     }

wallettemplate/src/main/java/wallettemplate/WalletSettingsController.java

@@ -28,6 +28,7 @@ import javafx.fxml.FXML;
 import javafx.scene.control.Button;
 import javafx.scene.control.DatePicker;
 import javafx.scene.control.TextArea;
+import org.bitcoinj.walletfx.overlay.OverlayWindowController;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.bouncycastle.crypto.params.KeyParameter;
@@ -47,7 +48,7 @@ import static org.bitcoinj.walletfx.utils.GuiUtils.informationalAlert;
 import static org.bitcoinj.walletfx.utils.WTUtils.didThrow;
 import static org.bitcoinj.walletfx.utils.WTUtils.unchecked;
 
-public class WalletSettingsController {
+public class WalletSettingsController implements OverlayWindowController<WalletSettingsController> {
     private static final Logger log = LoggerFactory.getLogger(WalletSettingsController.class);
 
     @FXML Button passwordButton;
@@ -55,10 +56,15 @@ public class WalletSettingsController {
     @FXML TextArea wordsArea;
     @FXML Button restoreButton;
 
-    public MainController.OverlayUI overlayUI;
+    private MainController.OverlayUI<? extends OverlayWindowController<WalletSettingsController>> overlayUI;
 
     private KeyParameter aesKey;
 
+    @Override
+    public void setOverlayUI(MainController.OverlayUI<? extends OverlayWindowController<WalletSettingsController>> ui) {
+        overlayUI = ui;
+    }
+
     // Note: NOT called by FXMLLoader!
     public void initialize(@Nullable KeyParameter aesKey) {
         DeterministicSeed seed = Main.bitcoin.wallet().getKeyChainSeed();

wallettemplate/src/main/java/wallettemplate/controls/ClickableBitcoinAddress.java

@@ -42,6 +42,7 @@ import javafx.scene.layout.Pane;
 import org.bitcoinj.core.Address;
 import org.bitcoinj.uri.BitcoinURI;
 
+import org.bitcoinj.walletfx.overlay.OverlayWindowController;
 import wallettemplate.Main;
 import org.bitcoinj.walletfx.utils.GuiUtils;
 import org.bitcoinj.walletfx.utils.QRCodeImages;
@@ -57,7 +58,7 @@ import static javafx.beans.binding.Bindings.convert;
  * address looks like a blue hyperlink. Next to it there are two icons, one that copies to the clipboard and another
  * that shows a QRcode.
  */
-public class ClickableBitcoinAddress extends AnchorPane {
+public class ClickableBitcoinAddress extends AnchorPane implements OverlayWindowController<ClickableBitcoinAddress> {
     @FXML protected Label addressLabel;
     @FXML protected ContextMenu addressMenu;
     @FXML protected Label copyWidget;
@@ -66,6 +67,10 @@ public class ClickableBitcoinAddress extends AnchorPane {
     protected SimpleObjectProperty<Address> address = new SimpleObjectProperty<>();
     private final StringExpression addressStr;
 
+    @Override
+    public void setOverlayUI(MainController.OverlayUI<? extends OverlayWindowController<ClickableBitcoinAddress>> ui) {
+    }
+
     public ClickableBitcoinAddress() {
         try {
             FXMLLoader loader = new FXMLLoader(getClass().getResource("bitcoin_address.fxml"));