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JavaFX and Lucene

Time:12-01

I am creating a search engine kind of project where i have to make a UI in JavaFX and use Apache Lucene for the queries. I am in a stage where the UI in JavaFX works perfectly on its own(without calling any Lucene methods) and the queries for the Lucene also work fine on its own(in a separate java project). When I try to combine the two by creating an Object of Lucene into the action performed when I press the ENTER button it crashes hard and the exception is far from confusing.

I am providing the code for both my Window and my LuceneTester classes and the exception thrown.

Main class:

public class Main extends Application {
    
    @Override
    public void start(Stage primaryStage) {
        new Window(primaryStage);
    }
    
    public static void main(String[] args) {
        launch(args);
    }
}

Window class

public class Window{

    public Window(Stage primaryStage) {
        VBox root = new VBox();
        root.getChildren().addAll(setSearch(), setBody());
        
        Scene scene = new Scene(root);
        primaryStage.setTitle("The Reuters Search Assistant");
        primaryStage.getIcons().add(new Image(getClass().getResourceAsStream("icon.png")));
        primaryStage.requestFocus();
        primaryStage.setMinWidth(1280);
        primaryStage.setMinHeight(720);
        primaryStage.setResizable(false);
        primaryStage.setScene(scene);
        primaryStage.show();
    }
    
    private VBox setSearch() {
        Label search = new Label("Search");
        search.setFont(new Font("arial", 30));
        search.setPadding(new Insets(5.0, 5.0, 5.0, 5.0));
        search.setAlignment(Pos.CENTER_LEFT);
        search.setTextAlignment(TextAlignment.LEFT);
        
        TextField searchBar = new TextField();
        searchBar.setFont(new Font("arial", 14));
        searchBar.setPromptText("type here");
        searchBar.setAlignment(Pos.CENTER_LEFT);
        searchBar.setOnKeyPressed(event -> {
            if (event.getCode() == KeyCode.ENTER) {
                searchAction(searchBar.getText());
            }
        });
        
        Separator separator = new Separator();
        separator.setOrientation(Orientation.HORIZONTAL);
        separator.setPadding(new Insets(5.0, 0, 0, 0));
        
        VBox searchPanel = new VBox();
        searchPanel.setAlignment(Pos.TOP_LEFT);
        searchPanel.setPadding(new Insets(5.0, 5.0, 0 ,5.0));
        searchPanel.setSpacing(5.0);
        searchPanel.fillWidthProperty();
        searchPanel.getChildren().addAll(search, searchBar, separator);
        return searchPanel;
    }
    
    private HBox setBody() {
        Button addBtn = new Button("Add Article");
        addBtn.setFont(new Font("arial", 20));
        addBtn.setMinWidth(170);
        addBtn.setOnMouseClicked(e -> {
            addArticleAction();
        });
        
        Button editBtn = new Button("Edit Article");
        editBtn.setFont(new Font("arial", 20));
        editBtn.setMinWidth(170);
        editBtn.setOnMouseClicked(e -> {
            editArticleAction();
        });
        
        Button delBtn = new Button("Delete Article");
        delBtn.setFont(new Font("arial", 20));
        delBtn.setMinWidth(170);
        delBtn.setOnMouseClicked(e -> {
            delArticleAction();
        });
        
        VBox buttonsBox = new VBox();
        buttonsBox.setAlignment(Pos.TOP_CENTER);
        buttonsBox.setMinWidth(200);
        buttonsBox.setPadding(new Insets(15.0, 5.0, 5.0, 5.0));
        buttonsBox.setSpacing(20.0);
        buttonsBox.getChildren().addAll(addBtn, editBtn, delBtn);
        
        Separator separator = new Separator();
        separator.setOrientation(Orientation.VERTICAL);
        
        ListView listView = new ListView();
        listView.setMinWidth(1050);
        listView.setMinHeight(574);
        
        VBox listViewBox = new VBox();
        listViewBox.setPadding(new Insets(5.0, 0, 0, 1.0));
        listViewBox.getChildren().add(listView);
        
        HBox bodyPanel = new HBox();
        bodyPanel.getChildren().addAll(buttonsBox, separator, listViewBox);
        return bodyPanel;
    }
    
    private void searchAction(String searchString) {
        System.out.println("Searching for : "   searchString);
        // Here is where the exception occurs.
        LuceneTester search = new LuceneTester(searchString);
    }
    
    private void addArticleAction() {
        System.out.println("add article");
    }
    
    private void editArticleAction() {
        System.out.println("edit article");
    }
    
    private void delArticleAction() {
        System.out.println("delete article");
    }
}

LuceneTester class

public class LuceneTester {
    
    String indexDir = "C:\\Users\\stefa\\eclipse-workspace\\TReSA\\index";
    String dataDir = "C:\\Users\\stefa\\eclipse-workspace\\TReSA\\data";
    Indexer indexer;
    Searcher searcher;
    
    public LuceneTester(String searchString) {
        try {
            this.createIndex();
            this.search(searchString);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (ParseException e) {
            e.printStackTrace();
        }
    }
    
    private void createIndex() throws IOException {
        indexer = new Indexer(indexDir);
        int numIndexed;
        long startTime = System.currentTimeMillis();
        numIndexed = indexer.createIndex(dataDir, new TextFileFilter());
        long endTime = System.currentTimeMillis();
        indexer.close();
        System.out.println(numIndexed   " File(s) indexed, time taken: "   (endTime-startTime)   " ms");
    }
    
    private void search(String searchQuery) throws IOException, ParseException {
        searcher = new Searcher(indexDir);
        long startTime = System.currentTimeMillis();
        TopDocs hits = searcher.search(searchQuery);
        long endTime = System.currentTimeMillis();
        System.out.println(hits.totalHits  " found. Time : "   (endTime - startTime)   " ms");
        for(ScoreDoc scoreDoc : hits.scoreDocs) {
            Document doc = searcher.getDocument(scoreDoc);
            System.out.println("File: "   doc.get(LuceneConstants.FILE_PATH));
        }
    }
}

Exception

Exception in thread "JavaFX Application Thread" java.lang.NoClassDefFoundError: org/apache/lucene/queryparser/classic/ParseException
    at com.TReSA.main.Window.searchAction(Window.java:116)
    at com.TReSA.main.Window.lambda$0(Window.java:52)
    at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
    at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:234)
    at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
    at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
    at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
    at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
    at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
    at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
    at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
    at javafx.base/javafx.event.Event.fireEvent(Event.java:198)
    at javafx.graphics/javafx.scene.Scene$KeyHandler.process(Scene.java:4105)
    at javafx.graphics/javafx.scene.Scene.processKeyEvent(Scene.java:2156)
    at javafx.graphics/javafx.scene.Scene$ScenePeerListener.keyEvent(Scene.java:2630)
    at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:218)
    at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:150)
    at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
    at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleKeyEvent$1(GlassViewEventHandler.java:250)
    at javafx.graphics/com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:424)
    at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:249)
    at javafx.graphics/com.sun.glass.ui.View.handleKeyEvent(View.java:548)
    at javafx.graphics/com.sun.glass.ui.View.notifyKey(View.java:972)
    at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:184)
    at java.base/java.lang.Thread.run(Thread.java:833)
Caused by: java.lang.ClassNotFoundException: org.apache.lucene.queryparser.classic.ParseException
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520)
    ... 29 more

Thanks in advance.

CodePudding user response:

The ClassNotFoundException: org.apache.lucene.queryparser.classic.ParseException means that there is a missing Dependency from Lucene, so you should check your build-tools setup.

But it also means that an Exception occurred so you might want to doublecheck if the Lucene only Code really works.

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