Files
sdrtrunk/src/main/java/io/github/dsheirer/gui/viewer/P25P2Viewer.java
2026-06-16 06:02:24 -04:00

765 lines
29 KiB
Java

/*
* *****************************************************************************
* Copyright (C) 2014-2026 Dennis Sheirer
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>
* ****************************************************************************
*/
package io.github.dsheirer.gui.viewer;
import com.google.common.eventbus.EventBus;
import io.github.dsheirer.controller.channel.Channel;
import io.github.dsheirer.gui.control.IntegerTextField;
import io.github.dsheirer.identifier.IdentifierUpdateNotification;
import io.github.dsheirer.identifier.configuration.FrequencyConfigurationIdentifier;
import io.github.dsheirer.identifier.patch.PatchGroupManager;
import io.github.dsheirer.message.StuffBitsMessage;
import io.github.dsheirer.module.decode.p25.P25FrequencyBandPreloadDataContent;
import io.github.dsheirer.module.decode.p25.P25TrafficChannelManager;
import io.github.dsheirer.module.decode.p25.phase1.message.P25FrequencyBand;
import io.github.dsheirer.module.decode.p25.phase1.message.P25P1Message;
import io.github.dsheirer.module.decode.p25.phase2.DecodeConfigP25Phase2;
import io.github.dsheirer.module.decode.p25.phase2.P25P2DecoderState;
import io.github.dsheirer.module.decode.p25.phase2.P25P2MessageFramer;
import io.github.dsheirer.module.decode.p25.phase2.P25P2MessageProcessor;
import io.github.dsheirer.module.decode.p25.phase2.enumeration.ScrambleParameters;
import io.github.dsheirer.record.binary.BinaryReader;
import io.github.dsheirer.util.ThreadPool;
import java.io.File;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;
import java.util.function.Predicate;
import java.util.prefs.Preferences;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javafx.application.Platform;
import javafx.beans.binding.Bindings;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.beans.value.ObservableValue;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.collections.transformation.FilteredList;
import javafx.collections.transformation.SortedList;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.control.Button;
import javafx.scene.control.CheckBox;
import javafx.scene.control.Label;
import javafx.scene.control.ProgressIndicator;
import javafx.scene.control.SelectionMode;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TablePosition;
import javafx.scene.control.TableView;
import javafx.scene.control.TextField;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.scene.input.Clipboard;
import javafx.scene.input.ClipboardContent;
import javafx.scene.input.KeyCode;
import javafx.scene.input.KeyCodeCombination;
import javafx.scene.input.KeyCombination;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Priority;
import javafx.scene.layout.VBox;
import javafx.stage.FileChooser;
import javafx.util.Callback;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* APCO25 Phase 2 viewer panel
*/
public class P25P2Viewer extends VBox
{
private static final Logger mLog = LoggerFactory.getLogger(P25P2Viewer.class);
private static final KeyCodeCombination KEY_CODE_COPY = new KeyCodeCombination(KeyCode.C, KeyCombination.CONTROL_ANY);
private static final String LAST_SELECTED_DIRECTORY = "last.selected.directory.p25p2";
private static final String LAST_WACN_VALUE = "last.wacn.value.p25p2";
private static final String LAST_SYSTEM_VALUE = "last.system.value.p25p2";
private static final String LAST_NAC_VALUE = "last.nac.value.p25p2";
private static final String FILE_FREQUENCY_REGEX = ".*\\d{8}_\\d{6}_(\\d{9}).*";
private Preferences mPreferences = Preferences.userNodeForPackage(P25P2Viewer.class);
private Button mSelectFileButton;
private Label mSelectedFileLabel;
private TableView<MessagePackage> mMessagePackageTableView;
private ObservableList<MessagePackage> mMessagePackages = FXCollections.observableArrayList();
private FilteredList<MessagePackage> mFilteredMessagePackages = new FilteredList<>(mMessagePackages);
private CheckBox mShowTS0;
private CheckBox mShowTS1;
private CheckBox mShowTS2;
private TextField mSearchText;
private TextField mFindText;
private Button mFindButton;
private Button mFindNextButton;
private ProgressIndicator mLoadingIndicator;
private IntegerTextField mWACNTextField;
private IntegerTextField mSystemTextField;
private IntegerTextField mNACTextField;
private Button mReloadButton;
private StringProperty mLoadedFile = new SimpleStringProperty();
private MessagePackageViewer mMessagePackageViewer;
public P25P2Viewer()
{
setPadding(new Insets(5));
setSpacing(5);
HBox fileBox = new HBox();
fileBox.setMaxWidth(Double.MAX_VALUE);
fileBox.setAlignment(Pos.CENTER_LEFT);
fileBox.setSpacing(5);
getSelectedFileLabel().setAlignment(Pos.BASELINE_CENTER);
HBox.setHgrow(getSelectFileButton(), Priority.NEVER);
HBox.setHgrow(getSelectedFileLabel(), Priority.ALWAYS);
fileBox.getChildren().addAll(getSelectFileButton(), getSelectedFileLabel());
HBox scrambleSettingsBox = new HBox();
scrambleSettingsBox.setAlignment(Pos.BASELINE_LEFT);
scrambleSettingsBox.setSpacing(5);
Label wacnLabel = new Label("WACN:");
Label systemLabel = new Label("SYSTEM:");
Label nacLabel = new Label("NAC:");
scrambleSettingsBox.getChildren().addAll(wacnLabel, getWACNTextField(), systemLabel, getSystemTextField(),
nacLabel, getNACTextField(), getReloadButton());
HBox filterBox = new HBox();
filterBox.setMaxWidth(Double.MAX_VALUE);
filterBox.setAlignment(Pos.BASELINE_CENTER);
filterBox.setSpacing(5);
Label searchLabel = new Label("Message Filter:");
HBox.setMargin(searchLabel, new Insets(0,0,0,15));
Label findLabel = new Label("Find:");
HBox.setHgrow(getFindText(), Priority.ALWAYS);
HBox.setHgrow(getSearchText(), Priority.ALWAYS);
Label showLabel = new Label("Show:");
HBox.setMargin(showLabel, new Insets(0,0,0,15));
filterBox.getChildren().addAll(findLabel, getFindText(), getFindButton(), getFindNextButton(), searchLabel,
getSearchText(), showLabel, getShowTS0(), getShowTS1(), getShowTS2());
VBox.setVgrow(fileBox, Priority.NEVER);
VBox.setVgrow(filterBox, Priority.NEVER);
VBox.setVgrow(scrambleSettingsBox, Priority.NEVER);
VBox.setVgrow(getMessagePackageTableView(), Priority.ALWAYS);
VBox.setVgrow(getMessagePackageViewer(), Priority.NEVER);
getChildren().addAll(fileBox, scrambleSettingsBox, filterBox, getMessagePackageTableView(), getMessagePackageViewer());
}
/**
* Extracts the channel frequency value from the bits file name to broadcast as the current frequency for each of
* the decoder states.
* @param file name to parse
* @return parsed frequency or zero.
*/
private static long getFrequencyFromFile(String file)
{
if(file == null || file.isEmpty())
{
return 0;
}
if(file.matches(FILE_FREQUENCY_REGEX))
{
Pattern p = Pattern.compile(FILE_FREQUENCY_REGEX);
Matcher m = p.matcher(file);
if(m.find())
{
try
{
String raw = m.group(1);
return Long.parseLong(raw);
}
catch(Exception e)
{
mLog.error("Couldn't parse frequency from bits file [" + file + "]");
}
}
}
return 0;
}
/**
* Processes the recording file and loads the content into the viewer
*
* Note: invoke this method off of the UI thread in a thread pool executor and the results will be loaded into the
* message table back on the JavaFX UI thread.
*
* @param file containing a .bits recording of decoded data.
*/
private void load(File file)
{
mLog.info("Loading File: " + file);
if(file != null && file.exists())
{
mLoadedFile.set(file.toString());
mMessagePackages.clear();
getLoadingIndicator().setVisible(true);
getSelectedFileLabel().setText("Loading ...");
int wacn = getWACNTextField().get();
int system = getSystemTextField().get();
int nac = getNACTextField().get();
ScrambleParameters scrambleParameters = new ScrambleParameters(wacn, system, nac);
ThreadPool.CACHED.submit(() -> {
List<MessagePackage> messages = new ArrayList<>();
P25P2MessageFramer messageFramer = new P25P2MessageFramer(null);
messageFramer.setScrambleParameters(scrambleParameters);
P25P2MessageProcessor messageProcessor = new P25P2MessageProcessor();
messageFramer.setListener(messageProcessor);
Channel empty = new Channel("Empty");
empty.setDecodeConfiguration(new DecodeConfigP25Phase2());
MessagePackager messagePackager = new MessagePackager();
//Setup a temporary event bus to capture channel start processing requests
EventBus eventBus = new EventBus("debug");
eventBus.register(messagePackager);
P25TrafficChannelManager trafficChannelManager = new P25TrafficChannelManager(empty);
trafficChannelManager.setInterModuleEventBus(eventBus);
//Register to receive events
trafficChannelManager.addDecodeEventListener(decodeEvent -> messagePackager.add(decodeEvent));
PatchGroupManager patchGroupManager = new PatchGroupManager();
P25P2DecoderState decoderState1 = new P25P2DecoderState(empty, 1, trafficChannelManager,
patchGroupManager);
decoderState1.setDecoderStateListener(decoderStateEvent -> messagePackager.add(decoderStateEvent));
decoderState1.addDecodeEventListener(decodeEvent -> messagePackager.add(decodeEvent));
P25P2DecoderState decoderState2 = new P25P2DecoderState(empty, 2, trafficChannelManager,
patchGroupManager);
decoderState2.setDecoderStateListener(decoderStateEvent -> messagePackager.add(decoderStateEvent));
decoderState2.addDecodeEventListener(decodeEvent -> messagePackager.add(decodeEvent));
decoderState1.start();
decoderState2.start();
long frequency = getFrequencyFromFile(mLoadedFile.get());
if(frequency > 0)
{
trafficChannelManager.setCurrentControlFrequency(frequency, empty);
FrequencyConfigurationIdentifier id = FrequencyConfigurationIdentifier.create(frequency);
decoderState1.getConfigurationIdentifierListener().receive(new IdentifierUpdateNotification(id,
IdentifierUpdateNotification.Operation.ADD, 1));
decoderState2.getConfigurationIdentifierListener().receive(new IdentifierUpdateNotification(id,
IdentifierUpdateNotification.Operation.ADD, 2));
}
//TODO: testing use - PCWIN TDMA Frequency Band as preload data
//ID:2 OFFSET:-45000000 SPACING:12500 BASE:851012500 TDMA BW:12500 TIMESLOTS:2 VOCODER:HALF_RATE
P25FrequencyBand band = new P25FrequencyBand(2, 851012500l, -45000000l, 12500, 12500, 2);
P25FrequencyBandPreloadDataContent content = new P25FrequencyBandPreloadDataContent(Collections.singleton(band));
messageProcessor.preload(content);
messageProcessor.setMessageListener(message -> {
if(!(message instanceof StuffBitsMessage))
{
// System.out.println(message);
//Add the initial message to the packager so that it can be combined with any decoder state events.
messagePackager.add(message);
if(message.getTimeslot() == P25P1Message.TIMESLOT_1)
{
decoderState1.receive(message);
}
else if(message.getTimeslot() == P25P1Message.TIMESLOT_2)
{
decoderState2.receive(message);
}
//Collect the packaged message with events
messages.add(messagePackager.getMessageWithEvents());
}
});
try(BinaryReader reader = new BinaryReader(file.toPath(), 200))
{
while(reader.hasNext())
{
ByteBuffer buffer = reader.next();
// System.out.println("Processing Bytes " + buffer.capacity() + " / " + reader.getByteCounter());
messageFramer.receive(buffer);
}
}
catch(Exception ioe)
{
ioe.printStackTrace();
}
Platform.runLater(() -> {
getLoadingIndicator().setVisible(false);
getSelectedFileLabel().setText(file.getName());
mMessagePackages.addAll(messages);
getMessagePackageTableView().scrollTo(0);
});
});
}
else
{
mLog.info("Can't load file: " + file);
}
}
/**
* Updates the filter(s) applies to the list of messages
*/
private void updateFilters()
{
Predicate<MessagePackage> timeslotPredicate = message ->
(getShowTS0().isSelected() && (message.getTimeslot() == 0)) ||
(getShowTS1().isSelected() && (message.getTimeslot() == 1)) ||
(getShowTS2().isSelected() && (message.getTimeslot() == 2));
String filterText = getSearchText().getText();
if(filterText == null || filterText.isEmpty())
{
mFilteredMessagePackages.setPredicate(timeslotPredicate);
}
else
{
Predicate<MessagePackage> textPredicate = message -> message.toString().toLowerCase().contains(filterText.toLowerCase());
mFilteredMessagePackages.setPredicate(timeslotPredicate.and(textPredicate));
}
}
/**
* Finds and selects the first row containing the text argument.
* @param text to search for.
*/
private void find(String text)
{
if(text != null && !text.isEmpty())
{
for(MessagePackage messagePackage: mFilteredMessagePackages)
{
if(messagePackage.toString().toLowerCase().contains(text.toLowerCase()))
{
getMessagePackageTableView().getSelectionModel().select(messagePackage);
getMessagePackageTableView().scrollTo(messagePackage);
return;
}
}
}
}
/**
* Finds and selects the first row containing the text argument, after the currently selected row.
* @param text to search for.
*/
private void findNext(String text)
{
if(text != null && !text.isEmpty())
{
MessagePackage selected = getMessagePackageTableView().getSelectionModel().getSelectedItem();
if(selected == null)
{
find(text);
return;
}
int row = mFilteredMessagePackages.indexOf(selected);
for(int x = row + 1; x < mFilteredMessagePackages.size(); x++)
{
if(x < mFilteredMessagePackages.size())
{
MessagePackage messagePackage = mFilteredMessagePackages.get(x);
if(messagePackage.toString().toLowerCase().contains(text.toLowerCase()))
{
getMessagePackageTableView().getSelectionModel().select(messagePackage);
getMessagePackageTableView().scrollTo(messagePackage);
return;
}
}
}
}
}
private MessagePackageViewer getMessagePackageViewer()
{
if(mMessagePackageViewer == null)
{
mMessagePackageViewer = new MessagePackageViewer();
mMessagePackageViewer.setMaxWidth(Double.MAX_VALUE);
//Register for table selection events to display the selected value.
getMessagePackageTableView().getSelectionModel().selectedItemProperty()
.addListener((observable, oldValue, newValue) -> getMessagePackageViewer().set(newValue));
}
return mMessagePackageViewer;
}
private IntegerTextField getWACNTextField()
{
if(mWACNTextField == null)
{
mWACNTextField = new IntegerTextField();
mWACNTextField.textProperty().addListener((ob, ol, ne) -> mPreferences.putInt(LAST_WACN_VALUE, getWACNTextField().get()));
int previous = mPreferences.getInt(LAST_WACN_VALUE, 0);
if(previous > 0)
{
getWACNTextField().set(previous);
}
}
return mWACNTextField;
}
private IntegerTextField getSystemTextField()
{
if(mSystemTextField == null)
{
mSystemTextField = new IntegerTextField();
mSystemTextField.textProperty().addListener((ob, ol, ne) -> mPreferences.putInt(LAST_SYSTEM_VALUE, getSystemTextField().get()));
int previous = mPreferences.getInt(LAST_SYSTEM_VALUE, 0);
if(previous > 0)
{
getSystemTextField().set(previous);
}
}
return mSystemTextField;
}
private IntegerTextField getNACTextField()
{
if(mNACTextField == null)
{
mNACTextField = new IntegerTextField();
mNACTextField.textProperty().addListener((ob, ol, ne) -> mPreferences.putInt(LAST_NAC_VALUE, getNACTextField().get()));
int previous = mPreferences.getInt(LAST_NAC_VALUE, 0);
if(previous > 0)
{
getNACTextField().set(previous);
}
}
return mNACTextField;
}
private Button getReloadButton()
{
if(mReloadButton == null)
{
mReloadButton = new Button("Reload");
mReloadButton.disableProperty().bind(Bindings.isNull(mLoadedFile));
mReloadButton.setOnAction(event -> load(new File(mLoadedFile.get())));
}
return mReloadButton;
}
/**
* List view control with message packages
*/
private TableView<MessagePackage> getMessagePackageTableView()
{
if(mMessagePackageTableView == null)
{
mMessagePackageTableView = new TableView<>();
mMessagePackageTableView.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);
mMessagePackageTableView.setPlaceholder(getLoadingIndicator());
SortedList<MessagePackage> sortedList = new SortedList<>(mFilteredMessagePackages);
sortedList.comparatorProperty().bind(mMessagePackageTableView.comparatorProperty());
mMessagePackageTableView.setItems(sortedList);
mMessagePackageTableView.setOnKeyPressed(event ->
{
if(KEY_CODE_COPY.match(event))
{
final Set<Integer> rows = new TreeSet<>();
for (final TablePosition tablePosition : mMessagePackageTableView.getSelectionModel().getSelectedCells())
{
rows.add(tablePosition.getRow());
}
final StringBuilder sb = new StringBuilder();
boolean firstRow = true;
for (final Integer row : rows)
{
if(firstRow)
{
firstRow = false;
}
else
{
sb.append('\n');
}
boolean firstCol = true;
for (final TableColumn<?, ?> column : mMessagePackageTableView.getColumns())
{
if(firstCol)
{
firstCol = false;
}
else
{
sb.append('\t');
}
final Object cellData = column.getCellData(row);
sb.append(cellData == null ? "" : cellData.toString());
}
}
final ClipboardContent clipboardContent = new ClipboardContent();
clipboardContent.putString(sb.toString());
Clipboard.getSystemClipboard().setContent(clipboardContent);
}
});
TableColumn timestampColumn = new TableColumn();
timestampColumn.setPrefWidth(110);
timestampColumn.setText("Time");
timestampColumn.setCellValueFactory(new PropertyValueFactory<>("timestamp"));
TableColumn validColumn = new TableColumn();
validColumn.setPrefWidth(50);
validColumn.setText("Valid");
validColumn.setCellValueFactory(new PropertyValueFactory<>("valid"));
TableColumn timeslotColumn = new TableColumn();
timeslotColumn.setPrefWidth(35);
timeslotColumn.setText("TS");
timeslotColumn.setCellValueFactory(new PropertyValueFactory<>("timeslot"));
TableColumn messageColumn = new TableColumn();
messageColumn.setPrefWidth(900);
messageColumn.setText("Message");
messageColumn.setCellValueFactory((Callback<TableColumn.CellDataFeatures, ObservableValue>) param -> {
SimpleStringProperty property = new SimpleStringProperty();
if(param.getValue() instanceof MessagePackage messagePackage)
{
property.set(messagePackage.toString());
}
return property;
});
TableColumn decodeEventCountColumn = new TableColumn();
decodeEventCountColumn.setPrefWidth(50);
decodeEventCountColumn.setText("Events");
decodeEventCountColumn.setCellValueFactory(new PropertyValueFactory<>("decodeEventCount"));
TableColumn decoderStateEventCountColumn = new TableColumn();
decoderStateEventCountColumn.setPrefWidth(50);
decoderStateEventCountColumn.setText("States");
decoderStateEventCountColumn.setCellValueFactory(new PropertyValueFactory<>("decoderStateEventCount"));
TableColumn channelStartCountColumn = new TableColumn();
channelStartCountColumn.setPrefWidth(50);
channelStartCountColumn.setText("Starts");
channelStartCountColumn.setCellValueFactory(new PropertyValueFactory<>("channelStartProcessingRequestCount"));
mMessagePackageTableView.getColumns().addAll(timestampColumn, validColumn, timeslotColumn, messageColumn,
decodeEventCountColumn, decoderStateEventCountColumn, channelStartCountColumn);
}
return mMessagePackageTableView;
}
/**
* File selection button
* @return button
*/
private Button getSelectFileButton()
{
if(mSelectFileButton == null)
{
mSelectFileButton = new Button("Select ...");
mSelectFileButton.onActionProperty().set(event -> {
FileChooser fileChooser = new FileChooser();
FileChooser.ExtensionFilter f1 = new FileChooser.ExtensionFilter("Demodulated Bitstream Recording (*.bits)", "*.bits");
FileChooser.ExtensionFilter f2 = new FileChooser.ExtensionFilter("All Files *.*", "*.*");
fileChooser.getExtensionFilters().addAll(f1, f2);
fileChooser.setSelectedExtensionFilter(f1);
fileChooser.setTitle("Select P25 Phase 2 .bits Recording");
String lastDirectory = mPreferences.get(LAST_SELECTED_DIRECTORY, null);
if(lastDirectory != null)
{
File file = new File(lastDirectory);
if(file.exists() && file.isDirectory())
{
fileChooser.setInitialDirectory(file);
}
}
final File selected = fileChooser.showOpenDialog(getScene().getWindow());
if(selected != null)
{
mPreferences.put(LAST_SELECTED_DIRECTORY, selected.getParent());
load(selected);
}
});
}
return mSelectFileButton;
}
/**
* Spinny loading icon to show over the message table view
*/
private ProgressIndicator getLoadingIndicator()
{
if(mLoadingIndicator == null)
{
mLoadingIndicator = new ProgressIndicator();
mLoadingIndicator.setProgress(-1);
mLoadingIndicator.setVisible(false);
}
return mLoadingIndicator;
}
/**
* Selected file path label.
*/
private Label getSelectedFileLabel()
{
if(mSelectedFileLabel == null)
{
mSelectedFileLabel = new Label(" ");
}
return mSelectedFileLabel;
}
/**
* Check box to apply filter to show/hide TS0 messages
* @return check box control
*/
private CheckBox getShowTS0()
{
if(mShowTS0 == null)
{
mShowTS0 = new CheckBox("TS0");
mShowTS0.setSelected(true);
mShowTS0.setOnAction(event -> updateFilters());
}
return mShowTS0;
}
/**
* Check box to apply filter to show/hide TS0 messages
* @return check box control
*/
private CheckBox getShowTS1()
{
if(mShowTS1 == null)
{
mShowTS1 = new CheckBox("TS1");
mShowTS1.setSelected(true);
mShowTS1.setOnAction(event -> updateFilters());
}
return mShowTS1;
}
/**
* Check box to apply filter to show/hide TS0 messages
* @return check box control
*/
private CheckBox getShowTS2()
{
if(mShowTS2 == null)
{
mShowTS2 = new CheckBox("TS2");
mShowTS2.setSelected(true);
mShowTS2.setOnAction(event -> updateFilters());
}
return mShowTS2;
}
/**
* Search text filter box
* @return text control for entering search text
*/
private TextField getSearchText()
{
if(mSearchText == null)
{
mSearchText = new TextField();
mSearchText.textProperty().addListener((observable, oldValue, newValue) -> updateFilters());
}
return mSearchText;
}
/**
* Text box for find text
*/
private TextField getFindText()
{
if(mFindText == null)
{
mFindText = new TextField();
mFindText.setOnKeyPressed(event -> {
if(event.getCode().equals(KeyCode.ENTER))
{
getFindButton().fire();
}
});
mFindText.textProperty().addListener((observable, oldValue, newValue) -> updateFilters());
}
return mFindText;
}
/**
* Find button to search for the text in the find text box.
* @return button
*/
private Button getFindButton()
{
if(mFindButton == null)
{
mFindButton = new Button("Find");
mFindButton.setOnAction(event -> find(getFindText().getText()));
}
return mFindButton;
}
/**
* Find next button to search for the text in the find text box.
* @return button
*/
private Button getFindNextButton()
{
if(mFindNextButton == null)
{
mFindNextButton = new Button("Next");
mFindNextButton.setOnAction(event -> findNext(getFindText().getText()));
}
return mFindNextButton;
}
}